INTRODUCTORY GUIDE

TO CRIME ANALYSIS AND MAPPING
Introductory Guide to Crime Analysis and Mapping 

Written by: 

Rachel Boba, Ph.D. 

Director, Crime Mapping Laboratory 

Police Foundation 

November 2001 

Report to the Office of Community Oriented Policing Services 

Cooperative Agreement #97-CK-WXK-004 

The opinions, findings, and conclusions or recommendations expressed in 

this document are those of the authors and do not necessarily represent the 

official position or policies of the U.S. Department of Justice. 
Acknowledgements 

3

Acknowledgements 

The author would like to thank Kristin Quayle for transcribing our training 

session during her summer here at the Police Foundation, as well as Mary 

Velasco and Erin Lane, Research Associates at the Police Foundation, for 

their careful review and comments.
Table of Contents 

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Page

I. Introduction............................................................. 8 

II. Introduction to Crime Analysis ............................. 9 

Definition of Crime Analysis................................................................... 9 

Types of Crime Analysis....................................................................... 11 

Intelligence Analysis .................................................................. 11 

Criminal Investigative Analysis ................................................. 12

Tactical Crime Analysis.............................................................. 13 

Strategic Crime Analysis............................................................ 13 

Administrative Crime Analysis .................................................. 14 

Crime Analysis Model ........................................................................... 15 

III. Introduction to Crime Mapping .......................... 17

Historical Overview ............................................................................... 17 

Types of Mapping .................................................................................. 18 

Manual Pin Mapping ................................................................... 18 

Computer Mapping ..................................................................... 19 

Geographic Information System (GIS)...................................... 19 

Crime Analysis Mapping ............................................................ 20 

GIS Components......................................................................... 20 

Data representation............................................................ 20 

Point feature ............................................................ 20 

Line feature ............................................................. 21 

Polygon feature ....................................................... 21 

Image feature .......................................................... 22 

Data of geographic features............................................... 23 

Point data ................................................................ 23 

Line data.................................................................. 24 

Polygon data ........................................................... 24 
Table of Contents 

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Page

GIS toolbox ........................................................................ 25 

Connectivity............................................................. 25 

Contiguity ................................................................ 26 

Geometry................................................................. 26 

Visual display/mapping ...................................................... 27 

Thematic approach.................................................. 27 

Scale ....................................................................... 28 

Querying GIS data ............................................................. 31 

Tabular queries ....................................................... 31

Spatial queries......................................................... 32 

IV. Introduction to Problem Solving ....................... 34 

Definition of Problem Solving .............................................................. 34

SARA Approach to Problem Solving ................................................... 34 

Scanning...................................................................................... 34 

Analysis ....................................................................................... 34 

Response..................................................................................... 35 

Assessment................................................................................. 35 

Crime Analysis and Problem Solving .................................................. 36 

V. Data and Geocoding ............................................ 37 

Types of Data ......................................................................................... 37 

Tabular Data ................................................................................ 37 

Geographic Data ......................................................................... 37 

General Data Integrity Issues ............................................................... 38 

Data Entry.................................................................................... 38 

Timeliness ................................................................................... 38 

Data Validity ................................................................................ 38 

Reliability..................................................................................... 39 

Data Transfer Process................................................................ 39 

Data Confidentiality/Privacy ...................................................... 39 
Table of Contents 

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Page

Data Management.................................................................................. 40 

Metadata ...................................................................................... 40 

Geocoding ................................................................................... 40 

Introduction ........................................................................ 40 

The geocoding process...................................................... 41 

Step 1: Prepare the geographic and 

tabular files for geocoding............................. 41 

Step 2: Specify geocoding parameters................... 45 

Step 3: Geocode ..................................................... 46 

Step 4: Review results............................................. 48 

Step 5: If necessary, respecify parameters

and geocode again. ...................................... 50 

Conclusion ......................................................................... 51 

VI. Spatial Analysis Techniques.............................. 52 

Single Symbol Mapping ........................................................................ 52 

Graduated Mapping............................................................................... 55 

Graduation By Size..................................................................... 55 

Graduation By Color................................................................... 57 

Classification Methods............................................................... 59 

Natural breaks.................................................................... 59 

Quantile.............................................................................. 60 

Equal area.......................................................................... 61 

Equal interval ..................................................................... 62 

Standard deviation ............................................................. 63 

Custom............................................................................... 65 

VII. Crime Analysis Product Format 

and Dissemination............................................ 67 

Factors to Consider............................................................................... 67 

Methods of Dissemination.................................................................... 67 

Components of Crime Analysis Products........................................... 68 
Table of Contents 

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Page

Types of Crime Analysis Products ...................................................... 68 

General Crime Analysis Product Elements......................................... 70 

Map Design Elements............................................................................ 71 

Evaluating the Utility of Crime Analysis and Mapping Products ...... 73 

VIII. References......................................................... 74 
Introduction

8

I. Introduction 

The following guide was developed from the curriculum for the “Introduction to 

Crime Analysis Mapping and Problem Solving” training course conducted by 

members of the Police Foundation’s Crime Mapping Laboratory in 2001 and funded 

by the Office of Community Oriented Policing Services (COPS). The purpose of this 

document is to convert the information presented in the training into a succinct and 

readable report that makes it available to a larger audience than was reached through 

the training sessions. It is not intended to be a comprehensive document on crime 

analysis, crime mapping, and problem solving, but rather a “starter” guidebook for 

someone just entering the field or a reference manual for current crime analysts or 

other law enforcement analysts. The format of the document follows the format of 

the training slides loosely, but it is not necessary to read them together. This 

document stands on its own. For further reading on crime analysis and mapping, see 

other relevant documents written by the Police Foundation at 

www.policefoundation.org or www.cops.usdoj.gov.
Introduction to Crime Analysis 

9

II. Introduction to Crime Analysis 

As an introduction to crime analysis, this section provides the definition of crime 

analysis as a general concept as well as definitions of five types of crime analysis. 

These definitions are used in the Police Foundation’s “Introduction to Crime Analysis 

Mapping and Problem Solving” course and have been created to synthesize current 

concepts and ideas in the field of crime analysis. These definitions are meant to 

enhance the understanding of crime analysis and to help create commonly understood 

terminology. The latter part of this section includes a hierarchical model by which all 

five types of crime analysis are related to one another. 

Definition of Crime Analysis 

The qualitative and quantitative study of crime and law enforcement 

information in combination with socio-demographic and spatial factors 

to apprehend criminals, prevent crime, reduce disorder, and evaluate 

organizational procedures.

Qualitative and quantitative. Crime analysis uses both qualitative and 

quantitative data and analytical techniques. Qualitative data and analytical 

techniques refer to non-numerical data as well as the examination and interpretation 

of observations for the purpose of discovering underlying meanings and patterns of 

relationships. This is most typical of field research, content analysis, and historical 

research. Quantitative data are data primarily in numerical or categorical format. 

Quantitative analysis consists of manipulations of observations for the purpose of 

describing and explaining the phenomena that those observations reflect and is 

primarily statistical. Crime analysis employs both types of data and techniques 

depending on the analytical and practical need. For example, crime data can be used 

in various ways, both quantitatively and qualitatively. The information such as date, 

time, location, and type of crime is quantitative in that statistics can be used to 

analyze these variables. On the other hand, narratives of crime reports are considered 

qualitative data in that a large number of narratives are nearly impossible to analyze 

statistically and are primarily examined to determine general themes and patterns. 

Study. Study is a systematic way of looking at crime and law enforcement 

information. That is, crime analysis is not examining information haphazardly but 

rather is applying formal analytical and statistical techniques as well as research 

methodology to law enforcement information according to the rules of social science. 
Introduction to Crime Analysis 

10 

Crime. In a law enforcement agency, the central focus is crime, both those reported 

to the police and those that are not. Thus, the central type of data analyzed is crime 

and the information surrounding it, such as arrests, offenders, victims, property, and 

evidence. 

Law enforcement information. In addition to crime, law enforcement agencies 

address many other issues and thus collect many other types of data. Examples of 

law enforcement data that are often available for crime analysts are calls for service 

(e.g., noise complaints, burglary alarms, suspicious activity), traffic information (e.g., 

accidents and citations), citizens’ perceptions (e.g., fear of crime, crime prevention 

behavior, satisfaction with the police), victimization, probation records, and parole 

information.

In combination with... This phrase refers to identifying patterns and studying 

relationships of crime and law enforcement data with other types of information, such 

as those listed below. 

Socio-demographic. This type of information refers to characteristics of 

individuals and groups such as sex, race, income, age, and education. On an 

individual (micro) level, socio-demographic information is used in law enforcement 

to search for and identify crime suspects. On a macro level, socio-demographic 

information is used to determine the characteristics of groups and how they relate to 

crime. For example, the information may be used to answer the questions, “Where 

can we find the suspect who is a white male, 30-35 years of age with brown hair and 

brown eyes?” or “Can demographic characteristics explain why one neighborhood has 

a higher rate of crime than another?” 

Spatial. The location where crimes or activities occur and the relationship of those 

places to one another and to other information is an important factor in the analysis of 

crime. It is not only important where a crime takes place but also the characteristics 

of those places and the environment in which the crime occurs. Thus, examination of 

spatial data such as streets networks, parcel information, orthophotographs, school 

locations, business and residential zoning, among others, is imperative for effective 

crime analysis. 

The last four key points describe the four goals of crime analysis. 

Apprehending criminals. The main function of crime analysis is to support law 

enforcement endeavors. One of the primary goals of law enforcement is the 

apprehension of criminals; consequently, one of the primary goals of crime analysis is 

to assist in the apprehension of criminals. For example, a detective may have a 

robbery incident in which the suspect has a snake tattoo on his left arm. The crime 

analysts may assist by searching a database of field incident cards to identify 
Introduction to Crime Analysis 

11 

individuals with such a tattoo. Also, a crime analyst may conduct a time of day/day 

of week analysis of burglary incidents that would assist officers in surveillance of an 

area to catch offenders. 

Prevent crime. Another primary goal of law enforcement is to prevent crime 

through methods other than apprehension. This goal lends itself particularly well to 

assistance from crime analysis. For example, members of the police department are 

conducting a crime prevention campaign about residential burglary and would like to 

target their resources in the areas that need it the most. Crime analysis can assist in 

planning community education and patrol response tailored to the problem by 

providing spatial analysis of residential burglary, analysis of how, when, and where 

the burglaries occurred, and analysis of what items were stolen. This information 

could be used to develop crime prevention suggestions such as closing and locking a 

garage door. 

Reduce disorder. Many criminologists contend that social disorder can lead to 

crime; that is, blight and other indicators of social decay left unchecked can attract 

crime and accelerate further decay. Thus, reducing disorder is a law enforcement 

objective and, by extension, one for crime analysis as well. Crime analysis can assist 

with these efforts by providing research and analysis of disorder indicators such as 

traffic accidents, noise complaints, or trespass warnings that can assist officers in 

addressing these issues before they become more serious problems. 

Evaluate organizational procedures. The fourth goal of crime analysis is 

assisting with the evaluation of organizational procedures. Several examples include 

resource allocation, the assessment of crime prevention programs, realigning 

geographic boundaries, forecasting staffing needs, and developing performance 

measures for the police department.

Types of Crime Analysis 

The following are five types of analysis that fall under the umbrella of crime analysis. 

As you will see, each contains characteristics of crime analysis in general, but each is 

specific in the type of data and analysis used as well as in its purpose. 

Intelligence Analysis 

The study of “organized” criminal activity, whether or not it is reported 

to law enforcement, to assist investigative personnel in linking people, 

events, and property. 

The purpose of intelligence analysis is to assist sworn personnel in the identification 

of networks and apprehension of individuals to subsequently prevent criminal 
Introduction to Crime Analysis 

12 

activity. A related goal is to link information together, prioritize information, 

identify relationships, and identify areas for further investigation by putting the 

analysis in a framework that is easy to understand. Much of the information analyzed 

in the field of intelligence analysis is not reported to the police by citizens but is 

gathered by law enforcement. Examples of data collection methods include 

surveillance, informants, and participant observation. In addition, the type of 

information is not limited to criminal information but can include telephone 

conversations, travel information, financial/tax information, and family and business 

relationships. Intelligence analysis has traditionally focused more or less on 

organized criminal activity, which includes drugs and prostitution syndicates. The 

data analyzed are plentiful and primarily qualitative, and thus are usually analyzed 

through qualitative methods. In light of the events of September 11, 2001, 

intelligence analysis has most recently begun to focus on terrorist activity at the local 

level as well. 

Criminal Investigative Analysis

The study of serial criminals, victims, and/or crime scenes as well as 

physical, socio-demographic, psychological, and geographic 

characteristics to develop patterns that will assist in linking together 

and solving current serial criminal activity. 

This type of analysis has also been called “profiling,” which is the process of 

constructing a “profile” of an unknown offender based on the nature of the crime, the 

facts of the case, and the characteristics of the victim. As with intelligence analysis, 

this type of analysis focuses primarily on qualitative data surrounding serious serial 

crimes such as murder and rape. Data are collected and analyzed on an individual 

level for those persons primarily or peripherally involved with the incidents. The 

spatial nature of the incidents and related locations such as the body dump sites or the 

encounter sites is also considered. The primary purpose of criminal investigative 

analysis is to develop patterns of serial crimes crossing city, state, and even national 

boundaries by linking behavior and evidence within and among incidents in order to 

catch the offender and/or clear cases. This is a very specific type of crime analysis 

that is primarily done on the federal law enforcement level since these types of crime 

occur infrequently and cross jurisdictional boundaries. 
Introduction to Crime Analysis 

13 

Tactical Crime Analysis 

The study of recent criminal incidents and potential criminal activity by 

examining characteristics such as how, when, and where the activity 

has occurred to assist in problem solving by developing patterns and 

trends, identifying investigative leads/suspects, and clearing cases. 

Tactical crime analysis focuses on information from recent crimes reported to the 

police. “Recent” can refer to the last few months or longer periods of time for 

specific ongoing problems. Tactical crime analysis also focuses on specific 

information about each crime such as method of entry, point of entry, suspects 

actions, type of victim, type of weapon used, as well as the date, time, location, and 

type of location. Field information such as suspicious activity calls for service, 

criminal trespass warnings, and persons with scars, marks, or tattoos collected by 

officers is also considered in the analysis. Although quantitative analysis is often 

conducted once a pattern has been identified, qualitative analysis, (i.e., critical 

thinking and content analysis) is used to identify patterns and trends initially. Three 

purposes of tactical crime analysis are 1) linking cases together and identifying the 

notable characteristics of the patterns and trends, 2) identifying potential suspects of a 

crime or crime pattern, and 3) clearing cases. The focus of tactical crime analysis is 

examining data daily in order to identify patterns, trends, and investigative leads for 

recent criminal and potential criminal activity. Once a crime pattern, suspect, or 

investigative lead is identified, the information is compiled and disseminated to patrol 

officers and detectives.

Strategic Crime Analysis 

The study of crime and law enforcement information integrated with 

socio-demographic and spatial factors to determine long term 

“patterns” of activity, to assist in problem solving, as well as to research 

and evaluate responses and procedures. 

Strategic crime analysis consists primarily of quantitative analysis of aggregate data. 

Monthly, quarterly, and/or yearly compilations of criminal and non-criminal 

information such as crime, calls for service, and traffic information are analyzed in 

aggregate form. That is, general categories such as date, time, location, and type of 

incident are analyzed instead of qualitative data such as narrative descriptions of 

incidents. Variables including race, class, sex, income, population, location, and 

location type are examined along with law enforcement information in the analysis 

process. The two primary purposes of strategic crime analysis are 1) to assist in the 

identification and analysis of long-term problems such as drug activity or auto theft 

and 2) to conduct studies to investigate or evaluate relevant responses and procedures. 

Both of these purposes correspond very well to the problem solving process (see 
Introduction to Crime Analysis 

14 

Section IV for a discussion of crime analysis and problem solving specifically). 

These types of studies include evaluation of crime prevention programs, in depth 

examination of a particular crime problem, and implementation of a survey of 

citizens’ perceptions of crime and the police. They incorporate pre- and postmeasurement as well as both impact and process evaluation methodology. Procedures 

examined include such activities as deployment and staffing, redistricting of beats or 

precincts, data entry and integrity, and the reporting process. In sum, strategic crime 

analysis uses statistical techniques and research methods to investigate long-term 

problems and evaluate organizational procedures. Analysts who primarily conduct 

strategic crime analysis are also called problem or research analysts. 

Administrative Crime Analysis 

The presentation of interesting findings of crime research and analysis 

based on legal, political, and practical concerns to inform audiences 

within law enforcement administration, city government/council, and 

citizens.

Administrative crime analysis is different from the previous types of analysis in that it 

refers to presentation of findings rather than to statistical analysis or research. The 

decision of what and how to present information is the primary focus of 

administrative crime analysis. Often, the type of information that is presented 

represents the “tip of the iceberg” of all the work and analysis that has previously 

been done, for example, an executive summary of a report. The purpose and the 

audience of the information determine “what” is presented along with legal (e.g., 

privacy and confidentiality), political (e.g., union issues, election concerns), and 

practical concerns (e.g., complexity of the information presented). The primary 

purpose of administrative crime analysis is to inform audiences. These audiences 

may vary from one situation to the next, which is why the type and quantity of 

information should vary as well. Audiences can be police executives, city council, 

media, citizens, and neighborhood groups or a combination. An excellent example of 

administrative crime analysis is the use of the Internet to provide information to the 

general public. Audiences of a police Internet site include citizens, police personnel, 

businesses, victims, criminals, and media—essentially everyone; therefore, the type of 

information published should be appropriate for an array of diverse customers. The 

information provided should be simple, clear, and concise and should not disclose 

sensitive information. One rule of thumb would be to only publish information that 

one would be comfortable seeing on the evening news.
Introduction to Crime Analysis 

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Crime Analysis Model 

The following figure displays how all of these types of crime analysis relate to one 

another in terms of the level of aggregation of the information. That is, types with 

low levels of aggregation focus on individual cases and used qualitative data and 

analysis techniques and those with high levels of aggregation focus on a limited scope 

of larger amounts of data and information. At the top of the figure, criminal 

investigative analysis and intelligence analysis utilize the least aggregated and most 

qualitative data. The data consist of information about informal networks of criminals 

and their non-criminal acquaintances and relatives as well as where individuals live, 

work, and “play.” The focus here is on the specifics of criminals, the nature of their 

crimes, their relationships, and their lives in general. 

Tactical crime analysis utilizes only crimes and activity reported to the police so the 

data are more aggregate and somewhat less abundant than those used for criminal 

investigative and intelligence analysis. Tactical crime analysis is primarily 

qualitative in nature but depending on the data, quantitative techniques can be used to 

describe characteristics of a given pattern such as the most common time the crimes 

occur (time series) or where the crimes are located in relationship to one another. 

Strategic crime analysis utilizes large amounts of data that are even more aggregated 

than tactical and investigative data. For example, information used in tactical crime 

analysis is primarily made up of crime incidents but includes such information as 

date, time, location, methods of the crime, and detailed description of the crime.

Strategic crime analysis focuses only on those variables that can be easily quantified, 

such as date, time, location, type of location, type of crime, and priority. Thus, the 
Introduction to Crime Analysis 

16 

type of analysis is more quantitative and the large amount of data calls for statistical 

operations instead of reading and examining each case individually. 

Finally, administrative crime analysis in this figure is literally the “tip” of the triangle 

in level of aggregation. The focus is presenting the most aggregate or summary 

information to a variety of audiences. 

Overall, these types of analysis fall under the general definition of crime analysis in 

that each one contains some of the key components of crime analysis. For the 

purposes of the rest of this report, we will focus on examples of the last three types of 

analysis, tactical, strategic, and administrative, as they are the types of analysis that 

are most likely to be conducted on a regular basis by a crime analyst in an average 

law enforcement agency. 
Introduction to Crime Analysis Mapping 

17 

III. Introduction to Crime Analysis Mapping

Historical Overview

The following chart is a brief outline of the history of crime mapping (taken from 

Weisburd and McEwen, 1997; and Harries, 1999). Mapping itself has a long history, 

but crime mapping specifically can be traced back to the early 1800s when social 

theorists began to create maps to illustrate their theories and research about crime. In 

relation to crime and policing, maps initially were used to examine issues like poverty 

or demographic characteristics and crime. One of the first police departments to use 

mapping was New York City in the 1900s. The maps consisted of simple wall maps 

in which “push pins” were used to indicate crimes that had occurred. During the 

1920s and 1930s, sociologists at the University of Chicago used mapping to examine 

crime and delinquency, specifically juvenile delinquency and related social 

characteristics. In the 1960s and 1970s, the first computer-generated maps of crime 

were created. (See Weisburd and McEwen, 1997 for more information). 

Early 1800s: Social Theorists: Single symbol point and 

graduated area maps 

1900s: New York City Police Department and 

others: Single symbol point maps, “pin maps” 

1920s-30s: Urban sociologists at the University of 

Chicago: Graduated area maps of crime and 

delinquency 

1960s-70s: First computer generated maps of crime 

1980s: Desktop computers available for mapping, 

but with limited quality; Environmental 

Criminology theory 

1990s: Desktop GIS and integration with law 

enforcement systems and data; government 

funding, etc. 

In the 1980s, more advanced technology and desktop computers became available, 

and more widely used. However, the quality of computerized mapping at that time 

was limited because of slow processing speeds and poor printing quality. At the same 

time, environmental criminology theory began to emerge, and academics began to 

examine the spatial characteristics of crime as well as how location characteristics 
Introduction to Crime Analysis Mapping 

18 

might contribute to criminal activity at particular locations over others. In the 1990s, 

desktop geographic information systems (GIS) became widely available, and in the 

late 1990s, they began to be generally used by law enforcement agencies and 

criminologists. 

Most recently in the late 1990s, Federal programs such as the Crime Mapping 

Research Center (National Institute of Justice) and the Crime Mapping and Analysis 

Program (National Institute of Justice, National Law Enforcement and Corrections 

Technology Center) were established. As part of its $1 billion Making Officer 

Redeployment Effective (MORE) program, from fiscal years1995-1998 and in fiscal 

year 2001, the COPS Office provided funds to law enforcement agencies to acquire 

crime mapping software and hardware. As with all MORE funded technology, the 

purpose of this software and hardware was to enhance community policing activities 

through timesavings and increased officer effectiveness. Since 1995, the Police 

Foundation’s Crime Mapping Laboratory has been funded by COPS to assist police 

agencies in incorporating crime mapping into their practices. In addition, universities 

and colleges have begun to offer undergraduate and graduate courses in crime 

analysis and crime mapping. 

Types of Mapping 

Manual Pin Mapping 

Wall maps have long been a simple and useful way to depict crime incidents or hot 

spots. Many police departments still have large maps tacked to the wall of the 

briefing room with the most recent crimes represented by pins. Although useful, 

manual wall maps, offer limited utility because they are difficult to keep updated, 

keep accurate, make easy to read, and can only display a limited amount of data. For 

example, although different colored pins could be used to represent different types of 

crime, date and time of incidents, the nature of incidents, and other information 

cannot be displayed easily. In order to update a manual wall map, for example, the 

pins must be removed each month. Unless a photo or some other mechanism is used 

to record the previous month’s map, the information illustrated on the map is lost. 

Thus, comparison is difficult, if not impossible, from one month to the next. Finally, 

the maps become unreadable when they display large amounts of data because of the 

numerous pins and/or holes.
Introduction to Crime Analysis Mapping 

19 

Computer Mapping 

The following is an example of a computer map. It has been taken from MapQuest©, 

an Internet mapping program, where an address is entered and a map of the 

surrounding area appears with a pin to locate the address. 

Even though it is possible to zoom in and out of this type of map, the geographic 

features (e.g., locations, streets, parks) are static and cosmetic only. In essence, a 

computer map is similar to a wall map, in that the computer is used to place a point at 

a specific location just as a person would put a pin on a wall map. Thus, computer 

maps have limitations similar to wall maps. For instance, when using MapQuest© to 

map an address, clicking on a point will not provide information behind that point, 

such as the specific address. While visually appealing and easy to use, computer 

mapping does not allow any more effective analysis than manual pin mapping. 

Geographic Information System (GIS)

A geographic information system (GIS) is a set of computer-based 

tools that allow a person to modify, visualize, query, and analyze 

geographic and tabular data. 

A GIS is a powerful software tool that allows the user to create anything from a 

simple point map to a three-dimensional visualization of spatial or temporal data. A 

GIS is different from manual pin maps and computer maps in that it allows the analyst 

to view data behind the geographic features, combine various features, manipulate the 

data and maps, and perform statistical functions. There are many different types of 

GIS programs, which include desktop packages (e.g., ArcView®, MapInfo®, 

GeoMedia®, Atlas GIS®, Maptitude®) as well as professional software (e.g., 

ArcInfo® and Intergraph®). 
Introduction to Crime Analysis Mapping 

20 

Crime Analysis Mapping 

“Crime mapping” is a term that has been used for the past few years to refer to 

research analysis using GIS in a law enforcement setting. In this report, the term 

crime analysis mapping is used to describe this process because using a GIS to 

analyze crime is not just the act of placing incidents on a map but also of analysis. 

Consequently, “crime analysis mapping” is: 

The process of using a geographic information system in combination 

with crime analysis techniques to focus on the spatial context of 

criminal and other law enforcement activity. 

GIS Components 

The following is a description of the major components of a GIS, which 

include data representation, data features, visualization, scale, and querying.

Data representation 

Real world data are represented by one of four features in a GIS. They include point, 

line, polygon, and image features. 

Point feature

A point feature is a discrete location that is usually depicted by a 

symbol or label. 

A point feature in the geographic information system is analogous to a pin placed on a 

paper wall map. Different symbols are used to depict the location of crimes, motor 

vehicle accidents, traffic signs, buildings, beat stations, and cell phone towers. The 

following map shows a robbery point map. 
Introduction to Crime Analysis Mapping 

21 

Line feature

A line feature is a geographic feature that can be represented by a line 

or set of lines. 

The following map shows how different types of geographic features such as 

railways, streets, and rivers can be represented by a line in a GIS. Additional 

examples are streams, streets, power lines, bus routes, student pathways, and lines 

depicting the distance from a stolen to a recovered vehicle. 

Polygon feature

A polygon feature is a multisided figure represented by a closed set of 

lines. 

In the following map, the largest blue polygon represents the city boundary, the green 

are census tracks, and the black are census block groups. Other examples of polygon 

features used in law enforcement would be patrol areas, beats, neighborhoods, or 

jurisdictions. Polygon features can represent areas as large as continents and as small 

as buildings. 
Introduction to Crime Analysis Mapping 

22 

Image feature

An image feature is a vertical photo taken from a satellite or a plane 

that is digitized and placed within the geographic information system 

coordinate system so that there are -x and -y coordinates associated 

with it. 

The following image is an example of an aerial photograph. Note that details of the 

streets, buildings, and environmental features such as landscaping are visible. 

There is a distinction between aerial photography (just the image) and digital 

orthophotography (the image combined with geometric qualities of the map). 

Because orthophotographs are located within the geographic information system, they 

can be viewed with other layers such as street or parcel information. The following 

image depicts a digital orthophotograph with the corresponding street network and 

parcel boundaries. 
Introduction to Crime Analysis Mapping 

23 

Data of geographic features 

Each type of feature has “attributes” or a table of data that describe it. All the 

attributes for three of the four types of features (point, line, and polygon) are stored in 

a GIS as a data table (Note that a digital orthophotograph has an –x and –y coordinate 

but does not have an associated data table worthy of analysis). The ability to view, 

query, relate, and manipulate data behind these features is the true power of a GIS. A 

manual pin map and a computer map depict points, lines, and polygons but do not 

have data associated with the features and are not easily manipulated. In a GIS, 

simply clicking on a point, line, or polygon can produce the data table associated with 

that particular feature.

Point data

The following is an example of point data taken from a GIS. The highlighted point 

has a corresponding data table, which describes the features. For instance, the yellow 

point is a robbery that occurred at 6:52 pm on January 1st, 1999. In this case, each 

line of data describes a different point on the map and each variable describes 

something about that point. 
Introduction to Crime Analysis Mapping 

24 

Line data

The following is an example of line data. The table describes the street segments 

(e.g., the miles, the length of that street segment, and the name of the street). The 

yellow street segment corresponds to the case highlighted in yellow in the data table. 

The GIS knows which line corresponds to each case in the table. 

Polygon data

The following image displays the data describing polygons, which are zip codes. The 

yellow polygon is zip code 20001 in Washington DC with an area of 2.22 square 

miles and a population of 30,050 in 1990 as is seen in the data table.
Introduction to Crime Analysis Mapping 

25 

Note that the lines themselves only make up the borders of the polygons, rather than 

being distinct lines with associated data. For example, the image, below left, depicts 

four intersecting line features that create a square. Each line has associated data; 

however, the area within the square or polygon that they have formed has no 

meaning. The image, below right, depicts similar lines; however, these lines are the 

borders for four separate beats and thus, the lines do not have meaning by themselves, 

only in relation to the other lines and in the fact that they create a shape. 

GIS toolbox 

The primary advantage of a GIS is its functionality that allows geographic data to be 

manipulated. The following are some components that enable data to be manipulated. 

Connectivity

Connectivity refers to streets and other linear features that are 

represented by segments that connect at intersections. 

As noted above, data are associated with each line feature. However, each segment 

connects at an intersection, and connectivity is the ability of the GIS to recognize that 

the two line segments come together to form an intersection. 
Introduction to Crime Analysis Mapping 

26 

Thus, connectivity allows intersections such as Shiawassee and Pine or Chestnut and 

Ottawa to be located on the map, which is particularly important in law enforcement 

data since accident information (reports and calls for service) usually list an 

intersection as the location of an accident. 

Contiguity

Contiguity refers to adjacent areas that are represented by adjacent 

polygons. 

The following map shows how a GIS includes adjacent polygons representing parcels 

and buildings. The ability of the GIS to recognize adjacent polygons allows for 

querying, selection of polygons within others, and visualization of complex land 

units.

Geometry

Geometry refers to the fact that all features in the geographic 

information system have at least one set of –x and –y coordinates. 

In the example depicted below, the point on the map has a distinct –x and –y 

coordinate which is listed in the yellow box. 
Introduction to Crime Analysis Mapping 

27 

Although these numbers may not make sense at first glance, they are an integral part 

of the GIS reference system, as every feature in a GIS has at least one –x and –y 

coordinate. For a point, the –x and –y feature is the center of the point. For a line 

segment or a polygon, the –x and –y coordinate is at the center of that particular line 

segment or polygon. Having an –x and –y coordinate for map features, especially 

points, is important because the location is more precise and there is no need for 

geocoding (see the explanation of geocoding later in the report). 

Visual display/mapping 

Thematic approach

 In a geographic information system, the data are separated by type of 

feature into what are called “layers” or “themes” as well as by type of 

data.

For example, point data of crime and calls for service would not be contained in the 

same layer or theme because these data come from two different sources. This is a 

thematic approach to organizing data. This component allows the data to be analyzed 

and visualized separately or together. Thus, when more than one layer is viewed in 

the GIS, they are stacked, similar to a stack of pancakes. In the following figure, 

each layer represents a different type of feature (point, line, polygon, or image) and a 

different type of data (shopping centers, bus routes, roads, and census tracts). 

In a GIS, how the layers are stacked is important since some layers are opaque and 

hide others. For example, orthophotographs are opaque and if placed on top will 

cover any layers underneath. 
Introduction to Crime Analysis Mapping 

28 

Scale

Scale is the relationship between the dimensions of the map and the 

dimensions of the Earth.

Usually, the scale depends on the purpose of the analysis or map. The following are 

examples of maps at various scales. 

The 48 contiguous states of the United States. 

The state of Texas and counties within it. 
Introduction to Crime Analysis Mapping 

29 

The city of Dallas, TX and major highways. 

Taken from ArcView® StreetMapTM 1.1 for Windows®. 

Street centerline map of several blocks. 

Taken from ArcView® StreetMapTM 1.1 for Windows®. 
Introduction to Crime Analysis Mapping 

30 

Land parcel of a block area. 

Parcel map with buildings. 
Introduction to Crime Analysis Mapping 

31 

Orthophotograph of a neighborhood. 

The appropriate scale depends on both the purpose of the map and the type of data 

that are displayed. For example, it would be impossible to view orthophotographs 

like the one above for the entire United States at one time. The GIS allows the user to 

set the scale at which orthophotographs are viewed (e.g., 1⁄2 mile or 1 mile). That 

way, the orthophotographs only become activated when the map is at that scale. 

Querying GIS data 

Geographic information systems contain the ability to query or select data in various 

ways. 

Tabular queries

In a GIS software program, query expressions can be created to select features both in 

the data and on the map. For instance, one can construct a query to select emergency 

calls for service (priority 0) from tabular calls for service data. 
Introduction to Crime Analysis Mapping 

32 

After running this query, the priority 0 calls are selected (highlighted yellow) in the 

table.

Additionally, the priority 0 calls are selected (highlighted yellow) on the map. 

Spatial queries

Spatial queries enable map features to be queried based on their location on the map 

or their location relative to other features. A very simple example is drawing a onemile buffer around a school to select the crimes that have occurred within a mile of 

the school.
Introduction to Crime Analysis Mapping 

33 

In addition, one can select a feature of a map based on its relationship to another 

feature. The following is an example of selecting zip codes (in yellow) that border any 

census tract in Washington D.C. 
Introduction to Problem Solving 

34 

IV. Introduction to Problem Solving 

The following is a brief discussion of problem solving. The source of the problem 

solving and SARA definitions as well as the location of extensive literature on 

problem solving is the Office of Community Oriented Policing Services (COPS) Web 

site at www.usdoj.gov/cops/cp_resources/pubs_prod/s5.htm.

Definition of Problem Solving

A methodical process for reducing the impact of crime and disorder 

problems in a community. The problem solving approach is an integral 

component of the philosophy of community policing.

SARA Approach to Problem Solving 

The SARA approach to problem solving is described as scanning (S), analysis (A), 

response (R), and assessment (A). That is, once a problem is identified and its 

characteristics are analyzed, a response is developed and deployed to combat the 

problem, and after a determined time period, the response is evaluated. The following 

is a brief discussion of each aspect of the SARA process. 

Scanning

Scanning is the first step to problem solving and is the identification of 

a cluster of similar, related, or recurring incidents through a preliminary 

review of information, and the selection of this crime/disorder problem 

among competing priorities for future examination. 

One example of using crime analysis information to scan for crime problems is 

comparison of crime on a monthly basis. Comparison of specific areas over time 

may indicate a problem area or type of crime. Another example is examining 

housebreaks over a six-month period to identify small patterns of activity, which 

could represent a larger housebreak problem. 

Analysis 

Analysis is the use of several sources of information to determine why 

a problem is occurring, who is responsible, who is affected, where the 

problem is located, when it occurs, and what form the problem takes. 

Often, individuals think they already know the nature and cause of problems 

identified in the scanning phase; thus, they do not conduct intensive analysis of the 
Introduction to Problem Solving 

35 

problem. However, analysis of the problem from several perspectives with several 

types of data often yields information not previously known. For example, while 

discussing the auto theft problem, detectives in a jurisdiction in the Southwest US 

insisted that the auto theft problem centered on cars being taken to Mexico. Yet, 

when the data were analyzed, it was discovered that nearly 85% of the vehicles were 

being recovered in or near the jurisdiction. The detectives did not have a good sense 

of the problem because they only saw a select few of the auto theft and recovery 

reports.

Response 

Response is the execution of a tailored set of actions that address the 

most important findings of the analysis phase. 

A recent report by Mike Scott, entitled Problem-Oriented Policing: Reflections on the 

First 20 Years, offers an evaluation of the last twenty years of problem solving and 

problem oriented policing and found that police departments are getting very good at 

responding creatively to the types of problems that they identify (Scott, 2000). Police 

departments are now working with communities and developing partnerships on a 

regular basis. Some examples of responses that have been used are working with city 

engineers to redesign a park that had a high number of assaults, vandalism, and drug 

dealing incidents (Mankato, MN); convening an advisory board composed of law 

enforcement, residents, business owners, and charities to address traffic and safety 

concerns at day-laborer gathering points (Glendale, CA); and establishing a juvenile 

diversion program whereby police bring together adolescent taggers and the owners 

of the property they deface to agree on terms for restitution and community service 

(Santa Ana, CA) (Sampson and Scott, 2000).

Assessment 

Assessment is the measurement of the impact(s) of the responses on 

the targeted crime/disorder problem using information collected from 

multiple sources, both before and after the responses have been 

implemented. 

For law enforcement agencies, assessment is probably the most challenging part of 

the SARA process, not only because measures of effectiveness are often difficult to 

determine and capture, but also because assessment takes time and effort to complete 

at a time when the problem solving process is winding down. For example, 

measuring a response such as a crime prevention education campaign is difficult 

because there may be substantial lag time between intervention and measurable 

effects of the response. 
Introduction to Problem Solving 

36 

Crime Analysis and Problem Solving 

Crime analysis and mapping play a major role in all phases of the problem solving 

process. It is important to measure the problem accurately during the scanning, 

analysis and the assessment phases. Analysts can also assist in the response phase of 

the SARA process by informing the effective allocation of resources by determining 

the times when, and areas where the offenses are most frequently or 

disproportionately occurring. The role of crime analysis in problem solving lies in the 

fact that members of a law enforcement agency have different experiences and 

understandings of a problem, and it is necessary for the crime analyst to either support 

or refute these assumptions by providing a comprehensive analysis of a problem and 

an evaluation of process and response impact.
Data and Geocoding 

37 

V. Data and Geocoding 

Types of Data 

Data collection and dissemination is a cyclical and on-going process. The term 

“database” can refer to anything from entire records management systems to simple 

spreadsheets containing a few variables and a handful of cases. Databases are vital 

for conducting crime analysis and mapping. It is essential to identify the actual and 

potential data sources within an agency that can be used for analysis. Below is a 

description of two distinct categories in which law enforcement information falls. 

Tabular Data

A list of records contained in a table that, along with information about 

the record, contain addresses or some other type of geographic 

variable.

The unit of analysis in tabular data can be anything that is not inherently geographic. 

Law enforcement examples of tabular data include crime, calls for service, accidents, 

field information, sex offender information, and arrests. 

Geographic Data

Data that are inherently geographic; that is, they describe geographic 

features.

The unit of analysis in geographic data is a geographic feature. Examples of 

quantitative geographic data sources include streets, districts, jurisdictions, census 

tracks, and bus stop/route data. Law enforcement examples of qualitative geographic 

data include neighborhood boundaries and pathways children take to and from school. 

Even though all geographic data have associated attributes (tabular data), the tabular 

data do not make much sense outside of a GIS. The following table contains the 

attributes of a geographic street file. Variables such as the length of the street in feet, 

prefix, street name, suffix, and number of lanes describe each street segment on the 

map.
Data and Geocoding 

38 

General Data Integrity Issues 

There are various data integrity issues associated with tabular and geographic law 

enforcement data. This section is not meant to serve as a comprehensive description 

of the data integrity issues in law enforcement but instead gives a general overview of 

the major issues. 

Data Entry

In a law enforcement setting, oftentimes the individuals, officers, dispatchers and 

records clerks, who are conducting data entry, do not realize that others are using the 

data they produce. This lack of awareness can lead to carelessness and result in 

unreliable data. Data entry errors can be improved by technology (address cleaning 

software), proper training, and making individuals aware of the uses and importance 

of the data.

Timeliness

A primary concern in crime analysis, especially in tactical crime analysis, is that data 

obtained are current and available in a timely manner. Unfortunately, because of 

human error and technological difficulties, this is not always possible. One method to 

remedy this problem is to stress the need for and the value of current data for crime 

analysis. This need should be communicated throughout the department in order to 

come up with solutions for improving data timeliness. 

Data Validity 

Validity refers to whether data accurately reflect the concept that they are intended to 

measure. Although true validity is difficult to measure, law enforcement data, like 

any other data, are prone to validity issues. For example, many police departments 

use calls for service information as a proxy for crime. This is problematic, because 

not all calls that are originally dispatched as a crime are in fact crimes. The best 

example is a robbery call for service, since there is a common confusion about the 

difference between a robbery and a burglary. A citizen who has been burglarized may 

call 911 to report, “they’ve been robbed” when in fact they were not. If the dispatcher 

enters what the citizen reports and the title of the call is not changed when the actual 

crime is determined (a common problem), the call for service would not accurately 

represent the crime that occurred. Even if the call title and crime match, using calls 

as a proxy for crime is problematic as the date and time variable would indicate when 

the call was received by the police department, not when the crime actually occurred. 

Analysis of these variables would yield invalid results in that they would indicate 

when the citizen called the police and not when the crime actually occurred. 
Data and Geocoding 

39 

Reliability 

Reliability refers to the whether data are measured the same in repeated observations. 

An example of a reliability issue related to law enforcement data is when there is a 

policy or law change (e.g., mandatory arrest for domestic violence offenses). 

Frequently, there will be a sharp increase or decrease that indicates that the data no 

longer represent the same phenomenon and thus, the numbers are not reliable. 

Obviously, reliability issues can significantly affect crime analysis results. 

Data Transfer Process 

The data transfer process can affect data quality and integrity in that data can be 

inadvertently or unavoidably lost or reformatted. An issue associated with the data 

transfer process is data compatibility. Police departments are notorious for having 

data in many different formats, and converting and combining these data is often a 

time-consuming and frustrating process. 

Data Confidentiality/Privacy 

Crime analysts are managers of law enforcement data; therefore, crime analysts are 

responsible for protecting the information and individuals represented within the data. 

Normally, the data used and created in crime analysis adheres to a jurisdiction’s 

policies on privacy and confidentiality. New situations of providing information have 

surfaced which require additional and more detailed policies such as the invention of 

the Internet and the use of mapping. Thus, police departments should include 

specific crime analysis concerns into their data-protection plan. 

On a related issue, the crime analysis unit, itself, should have a written data and 

analysis request policy that addresses common issues surrounding requests for crime 

analysis information. A policy, supported by the agency’s administration, can 

provide guidelines for requesting information and expectations of what will and will 

not be provided. A recent document published by the National Institute of Justice 

provides a discussion and suggestions specifically for mapping and data 

confidentiality, see www.ojp.usdoj.gov/cmrc/pubs/welcome.html to download or 

order a copy of the publication entitled, Privacy and the Information Age (Wartell and 

McEwen, 2001).
Data and Geocoding 

40 

Data Management 

Metadata

Metadata refers to the data that describes the analyst’s work. 

Metadata are the data that describe data. Every police department has its own set of 

procedures that outlines how crime analysis is conducted. Frequently, these 

procedures are kept only in the analysts’ memories, and it is important to have them 

written down for a variety of reasons. They include consistent data handling and 

cleaning procedures, guidelines for sharing work with others, keeping track of 

products and files created, and reducing duplication of effort. These written 

procedures are also invaluable training tools for new analysts. Some examples of 

categories of metadata include: 

!"Location of data files (e.g., on network, mainframe, personal computer) 

!"Source of the data (e.g., Records Management System, Investigation Bureau) 

!"Data cleaning procedures 

!"Geocoding procedures 

!"Report and map formats 

!"Methodology for regular reports and studies (e.g., monthly crime report, 

annual staffing analysis) 

Geocoding

The following discussion of geocoding is taken directly from another document 

produced by the Police Foundation’s Crime Mapping Laboratory as a part of the work 

conducted for COPS. The report is entitled, Geocoding in Law Enforcement (2000)

and can be found on both the Police Foundation (www.policefoundation.org) and 

COPS (www.cops.usdoj.gov) Web sites. 

Introduction 

Geocoding is the process of bringing tabular and geographic data together based on a 

common geographic unit of analysis. A geographic unit of analysis refers to a spatial 

characteristic within the data that is necessary to locate it on a map such as address, 

zip code, beat, or grid. Tabular data are contained in a table and are a list of records 

that, along with information about the record, contain addresses or some other type of 

geographic variable. Examples of law enforcement tabular data are calls for service, 

crime, accidents, citations, sex offenders, and arrests. Along with information about 

nature of the incident (e.g., type of call or crime, date, time), these data contain the 
Data and Geocoding 

41 

location of the incident (e.g., address, grid, and/or beat), which will allow it to be 

geocoded. Geographic data are data that can be displayed on a map such as streets, 

census tracts, parcels, and buildings. Examples of geographic data specific to law 

enforcement are police districts, beats, or grid boundaries. 

The purpose of geocoding is to assign tabular data to a location on the earth’s surface 

to visualize the spatial characteristics of the data. It is analogous to placing a pin on a 

map in the appropriate location. Unlike the paper map, when geocoding in a 

geographic information system, data associated with the pin, or data point, are 

available. In order to geocode either electronically or manually, there must be a 

common geographic unit of analysis. In law enforcement, address is primarily used 

as the geographic unit of analysis to which tabular data are geocoded. However, other 

types of geographic units are also used such as parcels, zip codes, census tracts, 

census blocks, or beats. In the case of geocoding, geographic data used for 

geocoding are called “reference data” since the geographic data are used to reference 

the tabular data.

The following is a discussion of the geocoding process, regardless of the geographic 

information system (GIS) software used, and some common problems faced when 

geocoding law enforcement data. 

The geocoding process 

In general, there are five basic steps in the geocoding process. They are: 

1. Prepare the geographic and tabular files for geocoding. 

2. Specify the geocoding parameters. 

3. Geocode. 

4. Review results. 

5. If necessary, respecify parameters and geocode again. 

Step 1: Prepare the geographic and tabular files for geocoding

The first step is preparing the tabular and geographic files, which is the most 

important and can be the most time consuming of the five steps. 

Tabular data. Tabular data used in law enforcement primarily consist of calls for 

service, crime, arrests, and accident data. Other types of tabular law enforcement data 

can include field information, sex registrant information, or intelligence information. 

In the past, much of this information was not captured electronically. However, 

currently, many departments either already have in place or plan to acquire an 

automated computer aided dispatch (CAD) system and a records management system 

(RMS) which have the capacity to store digital information as well as standardized 
Data and Geocoding 

42 

tables of addresses and location names. The most important aspects of these systems 

as they relate to geocoding are that they reduce the need for manual data entry and 

provide clear and consistent rules in order to ensure that data are reliable and valid.

Because individuals are the data entry mechanism, there is still the possibility of 

human error and inconsistencies, which is why training should coincide with the 

technology. 

Geographic data. A variety of geographic data types may be used as a reference 

layer, though street files such as the Census Bureau’s TIGER/Line ® files are the 

most commonly used. Street files are often called centerline files in that they depict 

the center of the streets by line segments. Details of curbs, alleys, or cul de sacs are 

not depicted in centerline files. In this context, street files are geographic databases 

containing records that describe interconnected street segments. More specifically, 

each street is broken down into sections with address ranges associated with them. 

These sections usually span between cross streets. The following map is an example 

of a street centerline file and the darkened line is one street segment. The table below 

is the data describing the streets. 

Street centerline databases generally have fields that describe the physical address 

along each street segment in the layer. Conventionally, addresses are recorded as 
Data and Geocoding 

43 

‘from’ and ‘to’ ranges for both the left and right sides of each street segment. In the 

above example, the centerline street segment of Yale Ave that is thicker than the 

others is represented by the address ranges of 83 to 173 on one side of the street and 

84 to 174 on the other side, as highlighted in the table. 

In addition to address ranges, street segments can be depicted by several variables 

such as street name, type, prefix, and suffix, as noted earlier. Street centerline 

databases vary in how the addresses are described. In the previous example, address 

is depicted with a variable called “street” along with the address ranges. The 

following are tables with highlighted examples of two additional ways in which 

addresses are found in a geographic database. The prefix and suffix fields are used to 

store information such as quadrant. The first table highlights a street segment with 

the prefix W for West Northern Ave. The second table highlights a street segment 

with the suffix NW for Chesterfield Place Northwest. Type refers to the type of 

roadway (e.g., street, road, lane, and drive). The highlighted examples in the 

following tables show Ave for Northern Avenue and Pl for Chesterfield Place. 

Because the Census Bureau’s mission to count and profile the nation’s people and 

institutions does not require a high level of positional accuracy in its geographic 

products, its TIGER/Line ® files and centerline maps are designed to show only the 

relative position of geographic elements. 
Data and Geocoding 

44 

As previously mentioned, another common layer used as a reference for geocoding is 

the parcel file. A parcel file is a polygon layer used to keep track of lots, 

subdivisions, and ownership information primarily for planning and tax purposes. 

The following is an example of how a parcel map looks in a GIS. Note that it is more 

specific than a centerline map in that alleys, cul de sacs, lot size, and street widths are 

discernable.

Parcel files provide a good base layer to examine relationships between land use, 

zoning, demographic data, and economic data as all of this information is contained in 

parcel files. Also, parcel reference layers can be very helpful in mapping law 

enforcement information because they can help to indicate the exact location of an 

incident (e.g., corner lot), and provide ownership information, which may prove 

valuable as in the case of rental property. 

While parcel files have the ability to be highly accurate, like street files, accuracy is 

largely dependent on how often and how well the files are maintained. Because of the 

nature of real estate and other planning mechanisms, keeping parcel files updated and 

accurate can be a full-time job for several technicians depending on the area. 

Successful geocoding depends not only on the quality of the geographic reference 

layer, but also the tabular data to be mapped. For any crime mapping application to 

be effective, basic reporting procedures need to be uniform and consistent. While 

most high-end geocoding software packages incorporate complicated algorithms 

Alley 

Individual lot 

Street width

Cul de sac 
Data and Geocoding 

45 

making them somewhat forgiving, a well established reporting procedure is often the 

best way to ensure a high rate of accuracy. 

Step 2: Specify geocoding parameters 

Step two consists of specifying the parameters of both the reference data and the 

tabular data to determine how the geographic units from each source will be matched 

successfully. 

Selection of which reference layer would be most effectively used for geocoding must 

consider the needs of the individual end user. Considerations of accuracy, cost of 

product, maintenance costs, utility, current reporting procedures, and compatibility 

with other existing reference layers must be dealt with on a case-by-case basis. In the 

case of law enforcement, most information is geocoded to the street reference layer. 

However, sometimes it is necessary to be more specific, in which case a parcel 

reference layer may be used. For example, one might use the street centerline file to 

pin map residential burglaries in an entire city since the exact location of the burglary 

would not be as important as getting a general idea of where the incidents are 

occurring throughout the city. On the other hand, one might use a parcel file to pin 

map residential burglaries in a one or two block area to determine exactly which 

houses were targeted and whether they were along alleys, wooded areas, or on the end 

of the block. 

Parameters set to determine how tabular and geographic data are matched are set 

within the GIS software and may include spelling sensitivity of the match, address 

style (e.g., whether to match on address only or address and zip code, or whether to 

accept partial match scores). A match score denotes the number of address records 

from the tabular file that were located in the reference layer. Another parameter is 

offset distance, which is placing a data point a predetermined distance away from the 

original geocoded location. This may be done to place points on one side of the street 

segment or another to make the map more readable and/or realistic. 

These parameters are choices within the GIS software that will affect the geocode 

match rate. These preferences should be set and modified only after an examination 

of the tabular data. One should be completely familiar with the data in order to set 

these preferences. For example, if the spelling sensitivity parameter is lowered in a 

city that has two streets named Mill and Miller, inaccurate geocoding may result. 
Data and Geocoding 

46 

Step 3: Geocode

Once the parameters are set, geocoding is just a push of a button that starts the 

geocoding process. Often, software packages use a fairly simple method to 

accomplish the actual placement of the tabular data in relation to the reference layer. 

The common approach is to place the address point along the street within the range 

of the street number. For example, this first table highlights one call for service at 

the address “292 Princeton Ave.”

The following table depicts the data for the street reference layer, and highlighted is 

the street segment in which “292 Princeton Ave” falls. 

When an incident is geocoded, the point is placed relative to a proportioned length 

derived from the ratio of the difference between the maximum and minimum address 

values and the physical length of the line segment. 

For example, a segment may represent a street with an address range of 101 to 151 for 

the left side. An address of 125 would be placed approximately halfway down the 

line on the left side. Although this method usually misses exact real world 

coordinates, it is often sufficient given the detail of the street file and necessary 

resolution of the final map. In this example, “292 Princeton Ave” is located near the 

beginning of the street segment. 
Data and Geocoding 

47 

As noted earlier, geocoding by street centerline may not be adequate to depict the 

exact location of an incident. In the case of mapping a few blocks of residential 

burglaries, one may want to geocode by parcel address. In some cases, such as 

recording traffic citations along routes that may not have readily discernable 

addresses, intersection address data can be recorded for later geocoding using street 

files. Intersection geocoding is often more accurate than street geocoding since there 

is no mathematical algorithm to define the physical location of the point generated; 

instead, the point is placed at the center of the intersection of the appropriate line 

segments. However, even using intersection data to geocode is not completely 

accurate since, in reality, most incidents occurring at an intersection address do not 

occur exactly in the middle of where the two streets intersect. 

A similar geocoding strategy uses polygons as opposed to previously discussed street 

centerline files. This method is the same as geocoding specific address data in that a 

value from the tabular data must match that of a geographic reference layer. For 

example, calls for service data often have a grid, beat, or district field in addition to an 

address field. In this case, the incident data has a census block number field. 

When geocoding polygons, the grid, beat, or district value is geocoded to the center of 

the polygon that represents the grid, beat, or district layer. In this example, the census 

block group layer matches that from the incident data. 
Data and Geocoding 

48 

Once the incident is geocoded, the point is placed in the exact middle of the polygon, 

as are all the points geocoded to that polygon. 

This type of geocoding is often used to create graduated color thematic maps by 

aggregating the data by polygon since data geocoded by polygon can no longer be 

located by address. However, many people geocode by address first and aggregate 

the data by polygon after the fact to avoid losing address data. Other types of 

geographic polygon data that can be used as reference layers for geocoding are zip 

codes, census blocks, census tracts, county, state, and country. Geocoding data at the 

polygon level is particularly useful when a dataset is very large or when address 

information is not as reliable as information such as grid or beat information. 

Step 4: Review results

Step four, reviewing results, is a matter of determining whether the geocoding process 

was successful and how successful it was. Most GIS software will have geocoding 

outcome statistics that indicate how many of the cases were successfully geocoded, 

how many are a partial match, and how many were not geocoded at all. Obviously, 

the ideal successful geocoding rate is 100%. Depending on the number of cases and 

the purpose of the analysis, a rate of 95% can also be acceptable. The important 

factor in accepting a geocoding rate less than 100% is understanding why some of the 

incidents are not geocoded. In some cases, missing data or data outside the mappable 

jurisdiction make up the incidents that are not geocoded. However, many times, 

there are other reasons that can and should be corrected.

In the case of a street centerline layer, geocoding problems are generally manifested 

in the form of missing or incorrect address ranges or missing street segments. Street 

layers often lack address ranges for streets because of recent construction of new 

roads or errors in the original creation process of the reference layer. The quality of 

these layers will depend both on those maintaining the layers and the growth rate of 

the jurisdiction. For example, in a small town that has not added new streets in fifty 
Data and Geocoding 

49 

years, the street reference layer would be easy to maintain, not only because nothing 

is being added but also because the town has relatively few streets to maintain. On 

the other hand, in a large city that is growing rapidly, the street layer would be much 

more difficult to maintain. 

Because street files are generally manually updated, they are also prone to data entry 

errors. The combination of these problems can be difficult to solve. Many agencies 

produce and maintain their own street centerline files or rely on their city or town’s 

engineering department to maintain them, and others have opted to purchase street 

centerline files that have been corrected and are bundled with contracts for regular 

updates. However, for layers particular to the police department, such as police 

district boundaries or beat boundaries, someone at the police department will most 

likely be tasked to maintain these. Fortunately, these layers are typically composed 

of many less geographic components than a street reference file. In any case, 

interagency cooperation can prove invaluable as a means for resolving geocoding 

problems.

Even if the geographic reference layers are complete, there may still be problems with 

the tabular data used by law enforcement agencies, which stem primarily from having 

incorrect information or inaccurate data entry. Address errors in calls for service, 

crime, or accident data are often the source of much of the woes of geocoding in law 

enforcement and can be categorized into five common types: incorrect street numbers, 

street name errors, direction errors, incorrect intersections (in the case of intersection 

geocoding), and discrepancy errors. 

!"Street number errors can be the result of entry mistakes and are frequently 

identified as range errors; the address identified is either less than or greater 

than the address range of the corresponding records in the source file. 

!"Street name errors can occur for a variety of reasons and are a result of the 

address record not matching the street name in the source database. These 

errors are among the most common, with reasons including misspellings, 

abbreviations, inconsistent street types, or lack of compliance with city 

addressing standards. 

!"Direction errors occur when the direction code of the address record does not 

match the direction code in the source database, either because they are 

incorrect or missing. 
Data and Geocoding 

50 

!"Unmatched intersections can result from inaccurate intersection addresses or 

incorrect format. For instance, the intersection of Main Street and Center 

Avenue is referred to as “Main St & Center Av” and will not be recognized by 

many GIS software packages if entered as “Main St/Center Av” or “Center Av 

& Main St.” 

!"Other errors can occur because there is a discrepancy between the common 

name of a location and the official address. For example, a police agency 

may have in its computer aided dispatch system a street called “Route 123,” 

but the official name in the street centerline file may be “US HWY 123;” thus, 

they will not match.

Step 5: If necessary, respecify parameters and geocode again.

Step five is only necessary when there is not a 100% geocoding rate, which seems to 

happen most of the time with law enforcement data. Once the data have been 

geocoded and problems have been determined by the geocoding process, there are a 

few solutions. Some may choose to take care of the problems by changing the 

preferences (e.g., lowering the spelling sensitivity). However, as noted earlier, this 

should be done cautiously and with full knowledge of the tabular and geographic 

datasets, as changing preferences such as spelling sensitivity can lead to incorrect 

address geocoding. 

Another solution is developing alias tables, which allow for multiple names for a 

single entity. For example, a location such as a park or a mall may be referred to in a 

computer aided dispatch system as “Central Park” or “Centertown Mall” instead of by 

address to make them easy for dispatchers to enter. An alias table would replace the 

common name with the appropriate address in the GIS system so it can be located on 

the map. However, even though alias tables are helpful, it is still recommended that 

data be cleaned in the original database to reduce confusion and facilitate consistency 

in data. Data are not only used for mapping purposes, so cleaning the data only in 

the GIS would not solve data integrity issues when the data are used elsewhere. 

The best way to correct data is to fix it at the source; in other words, bring the errors 

to the attention of those administering the computer aided dispatch system, to those 

maintaining the street centerline file, to the officers writing the reports, or to the 

clerks entering the data. However, this may not always be a realistic or a fast 

enough solution. In small projects or where a large number of cases share the same 

few mistakes, manual correction may be possible. Large datasets can often be 

corrected more efficiently when imported into a database or spreadsheet program 

which has a “search and replace” utility. In addition, specialized software programs, 
Data and Geocoding 

51 

referred to as “scrubbers” can be useful for large projects and in instances where data 

are regularly imported. 

Conclusion 

These five steps outline the general process of geocoding law enforcement data. 

Because the types of data, problems, and solutions are common among law 

enforcement agencies, there is much to learn and share with one another. This 

overview has not detailed the specific methodology of geocoding in a particular GIS 

software program since the software used varies from agency to agency. For a 

specific outline of how to geocode in particular GIS software applications, see the text 

manual or electronic help files accompanying the software. 
Spatial Analysis Techniques 

52 

VI. Spatial Analysis Techniques 

This section describes and illustrates basic types of mapping that are most commonly 

used and data classifications that are available in a GIS. This section is meant to 

serve as a guide and reference for these types of mapping rather than as a “how to” 

guide for creating crime analysis maps (please note that all of the data used here are 

fictional, and the maps do not have labels, scales, and North arrows that would be 

included in a map for presentation, as they are meant to illustrate a point and not 

represent a map for distribution. For elements of a map and final formatting, see 

section VII). For assistance in developing thoughtful, appropriate crime analysis 

maps, see the Manual of Map Production (2000) at www.policefoundation.org or 

www.cops.usdoj.gov produced by the Police Foundation’s Crime Mapping 

Laboratory as a part of the work conducted for COPS. 

Single Symbol Mapping 

Single symbol mapping refers to the use of individual symbols to 

represent point, line, and polygon features. 

The utility of single symbol maps is that they allow for a detailed analysis of small 

amounts of data. This following is an example of an inadequate single symbol map. 

This map has too much data for this scale, which is why this method is primarily used 

for small amounts of data.
Spatial Analysis Techniques 

53 

A drawback of single symbol mapping is that if two incidents have the same address, 

they are placed exactly on top of one another and cannot be differentiated by looking 

at the map. The following map is a better example of single symbol mapping that 

uses an appropriate scale. However, to avoid confusion since the points may still be 

placed on top of one another, one should list the number of incidents in the legend, as 

is done here or place a number (2) next to a location with more than one incident. 

Because single symbol maps are more useful for small amounts of data, they are 

particularly useful for tactical crime analysis and mapping crime patterns. In 

addition, they allow a more detailed look at the geography surrounding the incidents. 

For example, the following map illustrates the same burglary incidents as above with 

the land parcels drawn that show the number of houses on each block and which were 

burglarized. 
Spatial Analysis Techniques 

54 

The next map depicts the same data as well as centerline streets with the digitized 

orthophotograph of the neighborhood that shows the actual houses and surroundings 

of the burglary locations. 

Finally, this map depicts the parcels, orthophotographs, street centerlines, and 

burglary incident data together. This map could assist in determining additional 

characteristics of the burglary pattern by examining neighborhood characteristics such 

as proximity to alleyways or shrubbery, and in responding to the problem by 

determining potential surveillance locations. 

These maps could be used for a neighborhood analysis of accidents or burglary and 

provide a good example of the use of descriptive geographic data. The key to using a 

single symbol map effectively is for the analyst to be aware of the number of 
Spatial Analysis Techniques 

55 

incidents on the map and be sure they are all represented and their scale is 

appropriate.

Single symbol mapping is also helpful in representing geographic data such as 

schools or churches in that it is known that they are discrete addresses and the risk of 

two points on top of one another is low. The following is an example of schools in a 

single symbol map. The user should be aware of the readability of the map in order to 

determine what is “too much” data.

Graduated Mapping 

Graduated mapping consists of aggregating data into groupings that 

are displayed on the map. 

These groupings can be graduated by size or by color and can be classified 

statistically in various ways. This next section describes the size and color 

graduations as well as the classifications that are available in most GIS software 

packages. 

Graduation By Size 

Graduated size mapping is the process by which data are summarized 

so that symbols (point or line features) are altered in size to reflect the 

frequencies in the data. 

In other words, in this type of map, more than one incident at a given point or line is 

represented with a larger symbol or a thicker line. One drawback is that oftentimes, 

the size of the symbol or line is difficult to distinguish and the actual value associated 

with that symbol is not clearly displayed. In addition, similar to single symbol 
Spatial Analysis Techniques 

56 

mapping, this type of map is most helpful with smaller amounts of data, since too 

many incidents make the map unclear and difficult to read. The following map is an 

example where size is difficult to determine and points are overlapping. 

This type of map is more useful when mapping law enforcement tabular data when 

the scale is smaller, see below and at the top of the next page. 
Spatial Analysis Techniques 

57 

Graduation By Color 

In graduated color mapping, symbols (point, line, or polygon features) 

are altered in color to reflect a particular value of the feature. 

Features can be graduated by any variable. Law enforcement variables include 

shading by date/time, by priority, by crime type, by number of crimes at a location or 

in an area, or by crime rate of an area. The next map contains points that are shaded 

by their date of occurrence and shows the progression from older to the most recent 

incidents, which are in dark red However, each location must only represent one 

incident since it would be impossible to shade one point with data from two incidents. 

As with single symbol mapping, this map is most helpful when examining a small 

number of cases within crime patterns. 
Spatial Analysis Techniques 

58 

Points can also be shaded by a categorical variable. Each category or unique value is 

a different color. In the example, the priority of each domestic violence call is a 

different color. 

This method can also be used for line and polygon features. The next map is an 

example of parks shaded by whether or not they contain public bathroom facilities, 

which could impact the type of criminal activity in that park. 
Spatial Analysis Techniques 

59 

Classification Methods 

There are several different statistical methods for classifying numeric data in a GIS 

when creating both graduated size and graduated color maps. The same data are 

used in the respective point and polygon illustrations to show how different 

classification methods result in very different maps. Note that in each of the 

classifications, the user can also change the number of categories, which can also 

result in different maps of the same data. 

Natural breaks 

This is the default classification in most GIS programs and identifies 

the natural break points within the data using a statistical formula. 

The software program examines the selected data and their distribution, identifies 

natural break points, and creates the categories based on the best fit to the data. With 

each data set, the natural breaks classification would result in different ranges of 

categories; thus, the classification is “data dependent.” 

The following is an example of points graduated by size. Note in the legend that the 

categories do not make much sense, in that they are not evenly distributed or have 

equal number of values in each. This is because the ranges are determined by the GIS 

and the nature of the data distribution. 
Spatial Analysis Techniques 

60 

The following is an example of polygons graduated by color. 

Quantile 

Each class contains the same number of data points. 

That is, if there are 100 cases in the data, the GIS sorts them by their values and with 

five categories, includes the value range for the first 20 cases, the second 20, and so 

on. Similar to the natural breaks classification, the quantile classification is data 

dependent.

The following is an example of points graduated by size. Again, the categories do not 

make much sense, but if we were to look at the data we would see that there are the 

same number of cases in each category. 
Spatial Analysis Techniques 

61 

The following is an example of polygons graduated by color. 

Equal area 

This classification applies to polygon features only and determines 

categories so that the total area of the polygons in each class is 

approximately the same. 

This method is similar to the quantile classification; however, it looks to the square 

mileage or other appropriate units of the geographic areas in each class versus the 

number of data points. Thus, in a legend with five classifications, each category will 

contain polygons that make up 20% of the total area of the polygons in the analysis. 

The following is an example of polygons graduated by color. 
Spatial Analysis Techniques 

62 

Equal interval 

Divides the range of attribute values into equal size sub-ranges. 

The GIS determines the range of the values of the distribution and divides by the 

number of categories to determine the range. For example, if the number of assaults 

in all the beats of a city ranged from 1 assault to 100 assaults, the categories would be 

1-20, 20-40, 40-80, etc. Note that even though the categories seem to overlap, they 

in fact do not. In this case, all beats with 1 to 20 assaults would be in the first 

category, but beats with 20.00001 to 40 assaults would be in the second. Even if this 

is not realistically possible, it is mathematically possible, and it is very important to 

explain the breakdown system to those individuals using the maps. 

The following is an example of points graduated by size. In this case, the categories 

are even. This classification is still dependent on the data distribution, since as the 

range of the distribution changes so does the categories. For example, in a data 

distribution ranging from 1 to 200, the categories would be 1-40, 40-80 and so on, 

which is different than the categories in the example above. 
Spatial Analysis Techniques 

63 

The following is an example of polygons graduated by color. 

Standard deviation 

The mean value and standard deviations of the geographic features 

are computed, and the features are shaded according to which 

category they fall within. 

This classification does not display the actual values of the feature but shows 

categories of one, two, or three standard deviations above or below the mean. The 

values behind the classification can be viewed through another function, depending 

on the GIS software. This classification allows identification of outliers in a 

distribution and comparison of data with different distributions (would be displayed in 

two different maps), since the measures of a normal distribution give a common 

denominator of relative difference.
Spatial Analysis Techniques 

64 

The following is an example of points graduated by size. Once again, this 

classification is dependent on the data distribution. Notice that the mean value is not 

displayed on either one of these maps. Also, in this map there is only one standard 

deviation below the mean and two above. This indicates that most of the points fall 

closely around the mean. 

The following is an example of polygons graduated by color. 
Spatial Analysis Techniques 

65 

Custom 

User determined ranges. 

This is the only classification that is not determined by the software and by the 

characteristics of the data but by the analyst. This method is best for comparing 

crime or other law enforcement information over time. For instance, calls for service 

totals and the nature of the distributions tend to be different from month to month. If 

a classification that is data dependent is used, the colors or size of the symbols will 

vary in value from map to map. A custom range can be created in which the values 

for each color or size are the same every month and on every map, which allows 

comparison.

In order to create custom categories, one might use any of the previous classifications 

discussed here to get a sense of the data distributions. In addition, it is recommended 

that when doing a monthly or yearly comparison using custom ranges, that several 

months or years of data be examined to determine the most appropriate ranges. For 

this reason, it is best to make the upper limit of the highest range unlimited and use 

the phrase “or more” as a label (see below) to account for differences. Subjective 

considerations may also dictate the ranges. For example, in a department that fines 

properties with more than five false alarm calls for service, the graduation may 

distinguish between locations with more and less than five calls for service. 

The following is an example of points graduated by size. 
Spatial Analysis Techniques 

66 

The following is an example of polygons graduated by color. 
Crime Analysis Product Format and Dissemination 

67 

VII. Crime Analysis Product Format and Dissemination 

The effectiveness of any crime analysis or mapping endeavor has as much to do with 

the presentation of the results as it does the analysis. If the resulting document of 

analysis is not legible and understandable to its audience, it is worthless. The 

following is a discussion of factors to consider when developing a final product, such 

as methods of dissemination, components of a crime analysis product, and types of 

crime analysis products. Included also are recommendations for elements of a crime 

analysis product and elements of a map. These are distinguished from one another 

since maps include additional elements such as a legend, North arrow, and scale. 

Factors to Consider 

When developing a crime analysis product, one must consider both the purpose and 

audience of the product. Crime analysis products can serve many purposes, from 

informing citizens about recent activity, to assisting the agency in planning, to 

apprehending a suspected criminal. For example, monthly maps of a town that depict 

reported crime are useful for providing general information to the public about 

changes in hotspots of reported crime; however, a detailed map of each hotspot 

location may be necessary for patrol officers and investigators who need specific 

information in order to focus their problem solving efforts. In either case, it is 

important to prepare maps that are appropriate to the purpose. 

In addition, there are also many audiences for crime analysis products. They can 

include police department personnel, the general public, community groups, business 

groups, school officials, or city council members. By gauging the needs, 

expectations, and skill level of these individuals, products that are appropriate for 

each group can be developed. For example, a map of the residences of all known 

gang members that includes names and case numbers may be useful to gang 

enforcement officers compiling intelligence information. However, a map with this 

level of detail would not be disseminated to the public as it may violate an 

individual’s privacy rights or compromise an investigation. It may be appropriate to 

include a brief notation on the map, such as “law enforcement use only” or “external 

use” to indicate the intended audience. In general, when producing a crime analysis 

product, the needs of users of the information need to be balanced with political, 

legal, and ethical concerns. 

Methods of Dissemination 

Methods of dissemination of a product inherently rely on the intended purpose and 

audience. They also rely on the means available, such as the Internet and Intranet 

capabilities, reverse 911 technology, or the newspaper. For example, a crime analyst 
Crime Analysis Product Format and Dissemination 

68 

may want to let officers know that there is a sexual assault pattern happening in a 

certain part of the city and provide them with detailed information about the pattern. 

The analyst, of course, would not provide this information on the Internet for the 

public to see, but instead may include selected information on fliers to hand out at a 

briefing, send a department-wide (internal) e-mail, or attend the briefings of the 

officers in the affected areas. Thus, the purpose, informing the patrol officers in an 

area, dictates how that information should be disseminated.

The analyst must also consider what is the most efficient and effective method of 

dissemination, because frequently, the easiest method is not the most effective. For 

example, it may be simple to publish a crime pattern bulletin and e-mail it to the 

department or place fliers on a table in the briefing room for officers to read. But if 

the officers do not regularly check their e-mail or the table is full of other similar 

fliers, these methods of dissemination may be ineffective and a more time-consuming 

method, such as attending briefings, may be warranted. The most effective way to 

disseminate information depends on the current specific circumstances of the 

department, and the analyst should continually pay attention to what is appropriate 

and effective. 

Components of Crime Analysis Products 

A crime analysis product can include one or more of several types of analytical 

output, which can include tables, charts, graphs, maps, images, and narratives. In a 

law enforcement setting, a balance of one or more of these components should be 

used in any one product, and including all or just one component should be avoided. 

For example, a two-page essay on the recent burglary activity in Beat 33 will not be 

as effective as a simple description of the pattern, a table of the relevant information, 

a chart depicting the time of day and day of week of the activity, and a map that 

indicates where the activity is occurring. Conversely, a crime analysis product 

should not contain only a map or a chart. Even though a map or chart should be 

produced to stand on its own, the crime analyst should also include additional 

information such as interesting findings, interpretation of the results, and 

recommendations for future analysis. 

Types of Crime Analysis Products 

The following are some general types of crime analysis products. 

Crime bulletins. Short one to two-page documents that describe a tactical 

short-term trend or pattern. 
Crime Analysis Product Format and Dissemination 

69 

Memos. A document in letter form that summarizes a request, explains the 

analysis, highlights the interesting findings, and, in some cases, makes 

recommendations for response or further analysis. These should be included 

as cover letters for research and special reports.

Weekly/monthly/quarterly reports and maps. Documents and maps 

that convey the same information in regular intervals to inform about activity 

and allow for identifying problems. These products should be consistently 

formatted to ensure recognizability by customers and allow comparison. 

Annual reports. Reports that provide information aggregated by year and 

are published on a yearly basis. They would include breakdowns by 

geography, months, and types of activity (e.g., types of crime, types of calls, 

and accidents) and comparisons among years. They might also include 

comparisons to other similar jurisdictions as well as to state and national 

figures. 

Research reports. Reports that provide a description of the data, 

methodology, and analysis of a research project (i.e., problem solving project 

or evaluation of a program) as well as the results of the analysis, 

interpretations of the findings, and recommendations for response or future 

research.

Special reports. These are reports that are requested on an ad hoc basis and 

address a particular issue such as traffic accidents around schools or efficient 

allocation of a new squad of officers. The analysis that makes up these reports 

is less rigorous than the research reports and subsequently takes less time. 

These special reports make up much of the daily work of the crime analyst. 

These general categories can include information about crime, calls for service, 

arrests, and accidents. They also can be specific to a particular area such as street 

segment, neighborhood, beat, district, and the entire city. Other more specific types 

may include lists of incidents, “attempt to locate” bulletins, gang information 

bulletins, missing persons fliers, and FI card summaries. For template of such reports, 

see the Police Foundation’s product, Crime Analysis and Mapping Templates (2001) 

that are documents that provide guidelines and actual templates (computer files in 

which the analyst insert his/her own agency and analysis information) for producing 

these types of reports and maps. 
Crime Analysis Product Format and Dissemination 

70 

General Crime Analysis Product Elements 

The following are the general elements of a crime analysis product. 

Title. Includes the nature of the data and geography included as well as the 

time span included. For example, “Citizen Generated Calls for Service in 

Precinct 9: January 1, 2001 through June 30, 2001.” 

File path. This is where the document is located. This is important, so that 

future requests for the report, an update, or similar report can be easily filled. 

This assists the analyst in finding the product versus redoing it. An example: 

F:\Part I Crime 2001\Auto Theft\JanuaryReport.doc. 

Credits/date. This includes the name or divisions of the individual(s) who 

created the report and the date it was created. This allows for the analysts to 

get credit, for others to direct questions about the product to the appropriate 

people, and for everyone to know when the product was disseminated. For 

example, “Prepared by Crime Analysis Unit, December, 2001” or “Prepared 

by Jane Doe, 01/06/02.” 

Text, tables, graphics, and/or maps. This is the substantive content of 

the product and what is included varies from product to product. 

Analysis summary. This is an interpretation of the data and interesting 

findings and is important to ensure appropriate interpretations of the data and 

results by others. This section is often omitted from crime analysis products. 

Disclaimers. This information details what the data and analysis results do 

not say. For example, conclusions drawn from any report containing crime 

information can only be made about crimes known to the police, not all crime. 

Another example is the use of calls for service in lieu of crime data. The 

difference between the two data sources should be noted as should the 

limitations of using calls for service (e.g., time and date of call may not be 

time and date of the criminal incident). 

Recommendations. This section would contain suggestions for future 

analysis or actions based on the results. It is considered optional and may not 

always be included in a crime analysis product. 

Because these elements can be included and combined in an infinite number of ways, 

a specific example of a crime analysis product is not included here. See below for an 

example of the map design elements. 
Crime Analysis Product Format and Dissemination 

71 

Map Design Elements 

Maps differ substantively from other components of a crime analysis product, and 

they contain specific features unique to maps. The following are guidelines for map 

design elements. 

Title. Similar to the title of a general crime analysis product, the title of a 

map should contain the nature of the data and geography included as well as 

the time span included. 

Legend. This element lists the tabular and geographic data sources displayed 

in the map and indicates the symbols that are used to represent each data 

source. In addition, in the case of a map that includes graduation by color or 

size, the classification used should also be listed. This will allow the reader to 

understand the divisions of the categories and the analysis that has been 

conducted. For example, “Classification = Natural Breaks” or “Quantile 

Classification.”

Geocoding rate. As with statistics and tables that are presented in social 

science, data that are missing from the map should be noted. In the case of a 

map, this would be displayed as a percentage of the data that have been 

successfully geocoded. For example, “Geocoding Rate = 99%.” 

Labels. Should be used in moderation and where appropriate within the 

map. Labels should orient users to the map as well as highlight analytical 

results.

Scale Bar. Describes the distance units used in the map.

North Directional. Indicates the geographic orientation of the map. 

Credits/date. As in the general crime analysis product, this contains the 

name or division of the individual who produced the map as well as the date it 

was created. 

Remember, these elements are specific to maps and even though maps should 

basically stand on their own, supplemental description and interpretation of the 

analysis should be included. The next page shows an example of a map with all of 

these elements. 
Crime Analysis Product Format and Dissemination 

72 
Crime Analysis Product Format and Dissemination 

73 

Evaluating the Utility of Crime Analysis and Mapping Products 

Finally, a feedback mechanism for crime analysis products is important to determine 

both their relevance and effectiveness. Customer surveys, informal discussions, 

and/or focus groups can be used to learn whether a product is serving its intended 

purpose and is useful to its audience. In addition, it is necessary for the analysts 

themselves to review and reevaluate current crime analysis products. As noted in the 

following figure, this process is ongoing. Changes in focus of the department, 

capabilities of customers, the nature of criminal activity, and information technology 

are only a few of the factors that could influence needs and purposes of crime analysis 

products.
References 

74 

VIII. References 

Weisburd, D. and McEwen, T. 1998. “Crime Mapping and Crime Prevention.” In 

Crime Mapping and Crime Prevention: Crime Prevention Studies, Volume 8.

Weisburd, D. and McEwen, T. (eds.) Criminal Justice Press; Monsey, NY. Pp 

1-26.

Harries, K. (1999). Mapping Crime: Principle and Practice. US Department of 

Justice; Washington DC: 

Sampson, R. and Scott, M.S. (2000). Tackling Crime and Other Public Safety 

Problems: Case Studies in Problem-Solving. US Department of Justice, 

Office of Community Oriented Policing Services; Washington DC. 

Scott, M. 2000. Problem-Oriented Policing: Reflections on the First 20 Years. US 

Department of Justice, Office of Community Oriented Policing Services; 

Washington DC. 

Wartell and McEwen, 2001. Privacy and the Information: Age A Guide for Sharing 

Crime Maps and Spatial Data. US Department of Justice; Washington DC