Volume 2 Issue 1 | May 2009

Public Safety

Geography

A Quarterly Bulletin of Applied Geography for the Study of Crime & Public Safety

Residency Restrictions: What’s 

Geography Got to Do with It? 

Julie Wartell

San Diego County District Attorney’s Office

San Diego, California

During the summer of 2006 as the election season was heating up, Proposition 83, called Jessica’s Law, was on the California ballot. This proposition increased penalties for 

specific sex offenses,1 stipulated that all sex offenders had to wear global positioning system 

(GPS) anklets, and created a 2,000-foot residency restriction for all sex offenders around 

schools and parks where children “regularly gather.”

As the crime analyst for the San Diego County District Attorney’s Office, I was asked to 

create a variety of maps and spatial analyses to educate policymakers, law enforcement, and 

community organizations interested in understanding the consequences of Jessica’s Law. 

I worked with geographic information system (GIS) experts to determine the percentage 

of registered sex offenders living in zones that would be excluded by Jessica’s Law and find 

out which areas would not be excluded. Many jurisdictions across the country have been 

using geographic techniques to examine the effects of sex offender residency restriction 

laws, and the practice can help tell communities how restrictions will affect recidivism. 

Problematically, many of these studies have suggested that residency restrictions hamper 

offenders’ reentry process and make it more likely that they will not get treatment and will 

reoffend.

Our analysis of Jessica’s Law worked to provide realistic estimates of land availability for sex 

offender residency if the law passed. Much of the “available” land was open space or other 

nonresidential property, so we added land use and tax parcel data2 to create a better estimate 

of what land was available. To educate the San Diego community, we used the results of this 

analysis and a series of maps that showed the areas that would and would not be available 

for sex offender residency once the law went into effect.3

San Diego’s case study illustrates how using mapping and spatial analysis can help 

jurisdictions understand the effects of sex offender residency restrictions.4 Jurisdictions 

across the United States have used GIS to identify sex offender housing, analyze offenders 

and their movements, and allocate resources to supervise offenders and hold them 

accountable for their actions. GIS and global positioning systems can identify potential 

housing locations and analyze offenders’ whereabouts at all times of the day.

This issue of Geography & Public Safety discusses the Minnesota Department of Corrections’ 

geographic study of sex offender recidivism, the Pinellas County (Florida) Sheriff’s 

Department’s use of GIS and GPS, and a spatial analysis technique being piloted using 

California Department of Corrections data. In addition to the efforts completed by the 

Contents

1 Residency Restrictions: 

What’s Geography Got to 

Do with It? 

3 Right Place, Right Time: 

GPS Monitoring in Pinellas 

County

6 Residency Restrictions and 

Sex Offender Recidivism: 

Implications for Public 

Safety

9 Technical Tips

11 Geographic Research 

Suggests Sex 

Offender Residency 

Laws May Not Work

12 News Briefs

14 Resources

15 Geography and Public 

Safety Events
22

G&PS | May 2009

jurisdictions reporting in this bulletin, Texas,5

Iowa,6 and Colorado7 have been significant 

players in the debate over residency restrictions.

Much like the studies discussed in this bulletin, 

a number of published papers and web sites 

include important information about the 

geography of sex offender residency restrictions 

(see “Resources” on pg. 14). In addition, a 

recently published special issue of the Criminal 

Justice Policy Review was dedicated to the 

subject.8 Although most research findings imply 

that the effects of residency restrictions are 

negative, many states and local jurisdictions 

continue to implement new laws.

The California court system is still debating 

the residency restriction aspect of Jessica’s 

Law. In December 2008, the California 

Department of Corrections and Rehabilitation’s 

Sex Offender Management Board released 

a report on the effect of Jessica’s Law on the 

increasing homelessness of offenders. The 

report contributed valuable information to 

the debate about the negative aspects of sex 

offender residency restriction laws.9

 More and 

more frequently, jurisdictions are seeing value 

in studying the geography of the residency 

restrictions. We hope that in the future these 

geographic studies will have a greater effect on 

the legislative process.

Notes

1

Some of these penalties included mandatory minimum 

sentences for child molesters when victims were 

younger than 14 years old, consecutive full-term 

sentences for every forcible sex act, and mandatory 

minimum sentencing of life without the possibility of 

parole for the crimes of kidnapping and burglary with 

the intent to commit a forcible sex crime.

2

Tax parcel data are maintained by the County Tax 

Assessor and include geographically referenced 

information about every piece of property’s size, 

ownership, tax value, etc. 

3

More information about this analysis can be found at 

www.ojp.usdoj.gov/nij/events/maps/pittsburgh2007/

papers/Wartell2.pdf.

4

An overview of residency restriction laws has been 

published by the Council of State Governments, called 

Zoned Out: States Consider Residency Restrictions for 

Sex Offender. Read it online at: www.csg.org/policy/

pubsafety/documents/OutOfBoundsArticle.pdf.

5

In 1994, Texas was the first state to pass a sex offender 

residency restriction law (which established a “child 

safety zone”).

6

The Iowa County Attorneys Association issued a 

statement suggesting that residency restrictions do not 

provide needed protection and should be replaced with 

more effective measures, Statement on Sex Offender 

Residency Restrictions in Iowa. For more information, 

see: www.iowa-icaa.com/ICAA%20STATEMENTS/

Sex%20Offender%20Residency%20Statement%20

Dec%2011%2006.pdf, accessed February 16, 2009.

7

The Colorado Department of Public Safety’s Division 

of Criminal Justice published a report on whether 

sex offender residences affected community safety. 

The report, Report on Safety Issues Raised by Living 

Arrangements for and Location of Sex Offenders in the 

Community, is online at: dcj.state.co.us/odvsom/Sex_

Offender/SO_Pdfs/FullSLAFinal01.pdf.

8

More information is elsewhere in this Bulletin.

9

California Sex Offender Management Board, 

Homelessness Among Registered Sex Offenders in 

California: The Numbers, The Risks and The Response

(December 2008), www.casomb.org/docs/Housing%20

2008%20Rev%201%205%20FINAL.pdf.
3

I

n 2008, an 11-year-old boy disappeared 

from his home in Pinellas County, 

Florida, and his mother reported his 

disappearance to the police. The boy was 

located 5 days later and returned home. He 

told his mother that a man befriended him, 

gave him a place to live, took him shopping 

at Wal-Mart, and bought him walkie-talkie 

two-way radios to communicate. When the 

boy refused to identify the man, his mother 

began searching the Florida Department of 

Law Enforcement’s (FDLE) database of sex 

offenders. By using the mapping tools and 

search functions on FDLE’s web site, she 

was able to locate a sex offender, “Joshua,” 

who lived in the vicinity of her son and 

the school he attends. She reported her 

suspicions to the offender’s probation officer.

Florida’s use of mapping and monitoring 

devices has allowed law enforcement 

agencies to keep close watch on sex 

offenders, who must follow the mandates of 

parole conditions and residency restrictions 

laws. Officers can use global positioning 

system (GPS) and mapping applications to 

monitor violations and enforce sanctions. 

Citizens can find offenders in their area and 

report infractions. Joshua’s case provides an 

example of how GPS monitoring helped 

police absolve a suspect from an accusation 

of reoffending.

Florida’s Laws for Sex 

Offenders

Florida sex offenders like Joshua must obey 

three main residency restriction laws: Two 

of the laws restrict certain offenders from 

living within 1,000 feet of a day care center, 

school, park, playground, or other location 

where children congregate. The third law 

prohibits offenders from living near school 

bus stops.

Although sex offender laws were created 

to protect the public, recent studies 

conducted by the corrections departments 

of Minnesota and Colorado found that 

housing restrictions have minimal effect on 

sex offenders’ recidivism rates and could 

prevent them from stably reintegrating into 

society (Duwe, Donnay, and Tewksbury 

2008, 484–504; Department of Public 

Safety 2004). As the Iowa County Attorneys 

Association wrote in 2006, “Efforts to 

rehabilitate offenders and to minimize the 

rate of re-offending are more successful 

when offenders are employed, have family 

and community connections, and have a 

stable residence.” Residency restrictions 

may do more harm than good, and waste 

law enforcement resources when probation 

officers must monitor offenders for 

compliance. 

Monitoring Joshua 

Four years before he was reported as a 

recidivist suspect, Joshua was sentenced 

as a sexual offender after he sexually 

assaulted two girls. Following his release 

from jail, Joshua was kept under Florida 

Department of Corrections (FDOC) 

supervision with sanctions. He found a 

residence in a location that complied with 

his release conditions and began working 

as a flight mechanic. As he integrated back 

into society, he was required to follow the 

conditions of his release established by the 

courts. These included regular monitoring 

with a GPS device, so his probation 

officer could monitor his movements (see 

sidebar, “Active GPS Monitoring for Sex 

Offenders”). 

When Joshua received his court-imposed 

restrictions, a mapping program in the 

courtroom checked the address where he 

wanted to live. A 1,000-foot buffer was 

generated around the parcel and a report 

listed any home care facilities, day care 

centers, schools, or other places where 

children might congregate (see Figure 1). 

Although the automated system saves courts 

time and helps offenders find acceptable 

residence locations, the buffer can present 

difficulties for an offender trying to find 

a place to live. Because Pinellas County is 

densely populated, when the 1,000 foot 

buffer is created, there are few places left to 

live (see Figure 2).

 Joshua also reported to FDOC intake to 

receive the details of his release and the type 

of supervision imposed. His address was 

checked again, and the report was printed 

and placed in his file. Joshua’s sanctions 

included routine polygraph and drug 

tests, regular attendance in a sex offender 

treatment program, monthly checks for 

new arrests, a requirement to maintain 

a driving log, random computer checks, 

provision of all e-mail addresses and Instant 

Message logins, adherence to a curfew, and a 

requirement that he have an evacuation plan 

in the event of an emergency.1

While at the FDOC intake appointment, 

Joshua was registered with the Pinellas 

County Sheriff’s Office Sexual Predator and 

Offender Tracking (SPOT) Unit. Joshua’s 

picture was taken and his information 

Right Place, Right Time: GPS Monitoring in Pinellas County

Kristin Preston

Pinellas County Sheriff’s Office

Largo, Florida

Active GPS Monitoring 

for Sex Offenders

Global positioning system monitoring 

can help manage sex offenders. Sex 

offenders in Florida are considered 

high risk and actively monitored 

with GPS. The offender wears a 

radio transmitter on his or her ankle. 

Information from the transmitter 

goes to a GPS tracking device that 

logs the offender’s spatial position 

based on information from satellites. 

The device sends information to a 

server that analyzes it to see whether 

the offender is in a restricted area. 

Information about the offender’s 

spatial location and any violations are 

sent to a monitoring company and 

to the probation officer. Using this 

method, offenders can be monitored 

in real time. 
44

G&PS | May 2009

Figure 2. Pinellas County, Florida, with a 1,000-foot 

buffer around each home care, day care, and school.

Figure 1. The sex offender placement tool shows a 1,000-foot buffer around proposed 

home locations and reports whether home care, day care, schools, parks, and churches 

fall within the buffer.
5

updated (see sidebar, “The Sexual Predator 

and Offender Tracking Unit”). 

After Joshua completed his registration at 

the SPOT Unit, he went back to the FDOC 

office to receive the GPS monitor. He was 

fitted with the device and instructed on 

how to maintain connection to the satellite 

transmission. Settings were adjusted to adhere 

to Joshua’s restrictions while accommodating 

his schedule for attending sex offender 

treatment and work hours. The device was 

tested and GPS was acquired to make sure 

everything was working properly before 

Joshua went home (see Figure 3). Finally, the 

probation officer visited Joshua’s residence on 

the day he received the monitor to inspect the 

residence and neighborhood for the presence 

of children. 

Did Joshua Reoffend?

Joshua’s probation officer reviewed the GPS 

displays (or tracks) for the period that the 11-

year-old boy was missing from his home. The 

GPS monitoring application displays mapped 

tracks of the offender’s movements. Each point 

on the map includes the date, time, speed, and 

direction of the offender. After analyzing the 

offender’s movements and getting confirmation 

from Joshua’s employer and other witnesses, 

the officer determined that Joshua was not 

involved with the boy’s disappearance. The 

GPS tracks had established that Joshua was not 

in the vicinity of the boy who ran away or the 

Wal-Mart store where the walkie-talkie radios 

were purchased. 

Joshua’s case is an example of how Pinellas 

County and state law enforcement agencies 

have been working together to manage sex 

offender populations effectively and enforce 

residency restrictions using various mapping 

tools. These mapping tools enable both 

county and state agencies to validate sex 

offenders’ activities. Automated notification 

and placement tools perform distance 

analysis from the offender’s residence and 

provide a list of locations that may pose the 

potential for a violation. With these tools 

and investigative techniques, offenders can be 

included as suspects, or proven innocent, as 

in Joshua’s case. 

Notes

1

Because Florida regularly experiences evacuations 

because of hurricanes, and sex offenders cannot 

be near schools, which are the typical shelter for 

evacuations, sex offenders need to have a contingency 

plan for emergencies.

References

Department of Public Safety. Report on Safety Issues 

Raised by Living Arrangements for and Location 

of Sex Offenders in the Community. 2004. www.

dcj.state.co.us/odvsom/Sex_Offender/SO_Pdfs/

FullSLAFinal01.pdf. 

Duwe, Grant, William Donnay, and Richard 

Tewksbury. “Does Residential Proximity Matter?: 

A Geographic Analysis of Sex Offense Recidivism.” 

Criminal Justice and Behavior 35(2008): 484–504.

Iowa County Attorneys Association. Statement on 

Sex Offender Residency Restrictions in Iowa. www.

theparson.net/so/Iowa_prosecutors’_statement.pdf.

The Sexual Predator and 

Offender Tracking Unit

The SPOT Unit was created in 

2000 to address the growing 

number of sexual predators and 

sexual offenders within Pinellas 

County. In April 2006, the Pinellas 

County Board of Commissioners 

and the sheriff agreed to expand 

the Unit’s responsibilities to 

include all municipalities, thereby 

creating a countywide Unit. Their 

goals were to improve management 

practices, reduce duplication efforts 

by law enforcement agencies, 

maximize the use of human and 

financial resources, and improve 

accountability. 

The SPOT Unit is responsible for 

the following:

 Registering sex offenders. 

 Reregistering offenders every 3 

months. 

 Maintaining registration 

paperwork. 

 Notifying neighborhoods 

about sex offenders moving 

into the neighborhood. 

 Verifying offenders’ addresses. 

 Initiating criminal case 

processing when offenders 

violate registration. 

 Conducting surveillance 

operations. 

 Gathering and analyzing 

intelligence on offenses in the 

county. 

 Creating community 

awareness. 

The SPOT Unit’s database for 

mapping and maintaining detailed 

records for each offender lets the 

sheriff’s office provide supervision. 

When any crimes are reported in 

Pinellas County, the SPOT Unit 

uses GPS tracking to determine if 

any offenders were nearby. All law 

enforcement agencies in the county 

can access the detailed records 

and information that the Unit 

maintains.

Figure 3. A map of Joshua’s tracks on November 10, 2008 with a detailed report of 

Joshua’s locations.
66

G&PS | May 2009

I

n more than 25 states, legislation prohibits 

convicted sex offenders from living within 

close proximity (500 to 2,500 feet) of locations 

where children congregate (Meloy, Miller, 

and Curtis, 2008).1 Residency restrictions 

are designed to prevent sex offenders from 

gaining access to pools of potential victims 

and appear to make sense from a public safety 

perspective. But recent research suggests that 

such restrictions have almost no impact on 

sex offender recidivism and may compromise 

public safety. 

A number of recent studies have focused 

on the impact of residency restrictions on 

housing availability for sex offenders. They 

have generally found that residency restrictions 

diminish housing options in urban areas, 

forcing most sex offenders to move from their 

current homes to more rural locations. In doing 

so, these laws limit sex offenders’ access to social 

services and community resources that often 

ease the transition from the institution to the 

community (Chajewski and Mercado, 2009; 

Colorado Department of Public Safety, 2003; 

Zandbergen and Hart, 2006; Zgoba, Levenson, 

and McKee, 2009). Other research suggests 

that residency restrictions decrease employment 

opportunities for offenders and increase 

transience and homelessness (Levenson, 2008; 

Mercado, Alvarez, and Levenson, 2008).

To date, only a few studies have investigated 

the relationship between residential proximity 

and sexual recidivism. In 2003, the Minnesota 

Department of Corrections said that high-risk 

sex offenders did not reoffend more frequently 

when they lived in close proximity to schools or 

parks (Minnesota Department of Corrections, 

2003). The following year, Colorado researchers 

reported that sex offenders who recidivated 

were no more likely to live near places where 

children congregate than offenders who did 

not reoffend (Colorado Department of Public 

Safety, 2004). Last year, Blood, Watson, and 

Stageberg (2008) noted that the number of sex 

offense convictions involving the victimization 

of minors increased slightly2

 in the 2 years 

following the implementation of a residency 

restriction law in Iowa in 2005. 

Studying Sex Offender 

Recidivism in Minnesota 

Recently, several local governments in 

Minnesota have passed ordinances restricting 

the placement of sex offenders. To determine 

the effects that a statewide law might have on 

sexual recidivism in Minnesota, a group of 

researchers examined 224 sex offenders released 

from prison between 1990 and 2002 who had 

been reincarcerated for a new offense before 

2006 (Duwe, Donnay, and Tewksbury, 2008). 

Of the 3,166 sex offenders released from 

Minnesota prisons between 1990 and 2002, 

224 male offenders were reincarcerated for a 

new sex offense before 2006. Grant Duwe and 

colleagues analyzed the patterns of reoffending 

for these 224 offenders to determine whether 

new offenses might have been affected 

by residency restrictions. They examined 

the geographical relationship between the 

following:

 The offender’s residence

 The location where the offender first 

established contact with the victim

 The location where the offender 

committed the offense. 

Additionally, they looked at these 

considerations:

 Whether the offender was under 

supervision at the time of the offense

 The victim’s relationship with the offender

 Whether the offender used force (e.g., 

weapons, hand assault) and what kind of 

force was used

 Whether the victim or offender used 

alcohol or drugs.

Residency Restrictions and Sex Offender 

Recidivism: Implications for Public Safety

Grant Duwe

Minnesota Department of Corrections

St. Paul, Minnesota
7

To determine whether the 224 cases might 

have been affected by residency restrictions, 

Duwe and colleagues used the following 

four criteria: 

1. Offenders had to establish direct 

contact with their victims. 

2. The contact had to have occurred 

within 1 mile of the offender’s residence 

at the time of the offense. 

3. The first contact location with the 

victim had to have been near a 

school, park, day care center, or other 

restricted area. 

4. The victim had to have been younger 

than age of 18 at the time of the 

offense.

What the Researchers Did 

Duwe and colleagues collected information 

on the 224 offenses from several criminal 

justice and corrections databases.3 They 

used the “ruler” feature in Google Earth to 

calculate the straight-line distances between 

the offender’s home and the offense location 

and first contact location. Duwe and 

colleagues used all the data they collected to 

classify the 224 cases on the basis of whether 

they met the criteria outlined above. An 

offense had to meet all four of the criteria 

to be classified as one that might have been 

prevented by residency restrictions.

Residency Restrictions Do 

Not Deter Sex Offenses 

The results showed that none of the 224 sex 

offenses would likely had been deterred by a 

residency restriction law. 

As shown in Figure 1, most of the offenses 

occurred in the Minneapolis-St. Paul 

metropolitan area. Only 79 (35 percent) of 

the cases involved offenders who established 

direct contact with their victims.

The researchers could not estimate the 

distance between the offender’s residence 

and the location of the first contact with the 

victim for 13 of these cases because address 

information was missing for one of the 

locations (see Table 1). None of these cases, 

however, was likely to have been affected 

by residency restrictions, according to the 

research criteria. In 10 of the 13 cases, 

the victim was an adult. In the three cases 

involving juvenile victims, one offender met 

the victim through his occupation, and the 

other two offenders established romantic, 

“consensual” relationships with the victims, 

both of whom were 14 years old, after 

initiating contact at a nonrestricted location.

Among the cases where the first-contact 

distance was known, 28 offenders initiated 

victim contact within 1 mile of their own 

residence, 21 within 0.5 miles (2,500 feet), 

and 16 within 0.2 miles (1,000 feet). The 

victim was younger than 18 years old in 

16 of the 28 cases. But none of these 16 

Figure 1. Offense locations for 224 sex offender recidivists, 1990–2005.

 Table 1. Offender Residence—First Contact Distances for Direct-Contact Offenders 

Distance Number Percent

Less than 1,000 ft. (0.19 miles) 16 20.3

1,000–2,500 ft. (0.20–0.47 miles) 5 6.3

2,501–5,280 ft. (0.48–0.99 miles) 7 8.8

1–2 miles 6 7.6

3–5 miles 10 12.7

6–10 miles 4 5.1

11–20 miles 4 5.1

Greater than 20 miles 7 8.8

Telephone 4 5.1

County Jail/Halfway House 2 2.5

Internet 1 1.2

Unknown 13 16.5

Total 79 100.0
88

G&PS | May 2009

cases involved offenders who established victim 

contact near a school, park, or other prohibited 

area. Instead, these 16 offenders typically used a 

ruse to gain access to their victims (victims were 

often their neighbors). 

Residential proximity did not affect the 224 

sex offenses for several reasons: The researchers 

observed that sexual recidivism was affected by 

social or relationship proximity, not residential 

proximity. Most of the offenders victimized 

someone they knew, which helps explain 

why 85 percent of the offenses occurred in a 

residential location such as the offender’s home. 

Furthermore, 113 of the 224 cases involved 

offenders who gained access to their victims 

through another person, typically an adult. 

For example, a male offender may develop a 

romantic relationship with a woman who has 

children. The sex offender recidivists would use 

these relationships to gain access to the women’s 

children. 

Sex offenders rarely established direct contact 

with victims near their own homes. Sex 

offenders would be recognized more easily in 

their own neighborhoods, which may have 

made them directly contact victims elsewhere. 

When these offenders look for a victim, they 

usually go to an area within 20 miles of their 

residence, but still far enough away (more 

than 1 mile) to decrease the chances of being 

recognized. Although residency restrictions 

target sex offenders who initiate contact with 

juvenile victims, the 79 offenders who made 

direct contact with victims tended to victimize 

adults more frequently than juveniles. 

Conclusion 

Results from this and other studies suggest 

that residency restrictions would have, at best, 

only a marginal effect on sexual recidivism. 

Recent research has found that a lack of stable, 

permanent housing increases the likelihood 

that sex offenders will reoffend and abscond 

from correctional supervision (Meredith, Speir, 

and Johnson, 2007; Williams, McShane, and 

Dolny, 2000). By making it more difficult 

for sex offenders to find suitable housing and 

successfully reintegrate into the community, 

residency restrictions may actually compromise 

public safety by fostering conditions that 

increase offenders’ risk of reoffending. 

Notes 1

These locations include schools, parks, and day care 

centers.

2

The researchers did not report tests of statistical 

significance.

3

The authors used the Statewide Supervision System 

(S3), the Minnesota Bureau of Criminal Apprehension 

offender registry, and the Minnesota Department of 

Corrections’ Correctional Operations Management 

System (COMS).

References 

Blood, Phyllis, Lanette Watson, and Paul Stageberg. State 

Legislation Monitoring Report: FY 2007. Des Moines, 

Iowa: Iowa Department of Human Rights: Division of 

Criminal and Juvenile Justice Planning, 2008.

Chakewski, Michael, and Cynthia Calkins Mercado. 

“An Evaluation of Sex Offender Residency Restriction 

Functioning, in Town, County, and City-Wide 

Jurisdictions. Criminal Justice Policy Review 20(2009): 

44–6.

Colorado Department of Public Safety. Report on Safety 

Issues Raised by Living Arrangements for and Location of 

Sex Offenders in the Community. Denver, Colorado: Sex 

Offender Management Board, 2004.

Duwe, Grant, William Donnay, and Richard 

Tewksbury. “Does Residential Proximity Matter? A 

Geographic Analysis of Sex Offense Recidivism.” 

Criminal Justice and Behavior 35(2008): 484–504.

Iowa County Attorneys Association. Statement on Sex 

Offender Residency Restrictions in Iowa. Des Moines, 

Iowa: Iowa County Attorneys Association, 2006. 

Levenson, Jill. “Collateral Consequences of Sex 

Offender Residence Restrictions.” Criminal Justice 

Studies 21(2008): 153–166.

Meloy, Michelle L., Susan L. Miller, and Kristin 

M. Curtis. “Making Sense Out of Nonsense: The 

Deconstruction of State-Level Sex Offender Residence 

Restrictions.” American Journal of Criminal Justice

33(2008): 209–222.

Mercado, Cynthia C., Shea Alvarez, and Jill S. 

Levenson. “The Impact of Specialized Sex Offender 

Legislation on Community Re-entry.” Sexual Abuse: A 

Journal of Research and Treatment 20(2008): 188–205.

Meredith, Tammy, John Speir, and Sharon Johnson. 

“Developing and Implementing Automated Risk 

Assessments in Parole.” Justice Research and Policy

9(2007):1–21.

Minnesota Department of Corrections. Level Three Sex 

Offenders Residential Placement Issues. St. Paul, Minnesota: 

Minnesota Department of Corrections, 2003.

Williams, Frank, Marilyn D. McShane, and H. Michael 

Dolny. “Predicting Parole Absconders.” Prison Journal

80(2000): 24–38. 

Zandbergen, Paul A., and Timothy C. Hart. “Reducing 

Housing Options for Convicted Sex Offenders: 

Investigating the Impact of Residency Restriction Laws 

Using GIS.” Justice Research and Policy 8(2006):1–24.

Zgoba, Kristin, Jill Levenson, and Tracy McKee. 

“Examining the Impact of Sex Offender Residence 

Restrictions on Housing Availability.” Criminal Justice 

Policy Review 20(2009):91–110.
9

The Challenge

The California Department of Corrections 

and Rehabilitation (CDCR) has begun 

tracking more than 6,000 sex offender 

parolees by using global positioning system 

(GPS) anklets. Sex offender parolees are 

allowed to travel only through certain areas 

and must keep away from other people. 

The GPS device lets parole agents know 

when parolees are somewhere they should 

not be by logging GPS coordinates every 

minute and sending coordinates to a central 

server every 10 minutes. This information 

about parolee location is compared to 

law enforcement incident data through 

crime-scene correlation reports. Regular 

e-mail reports keep analysts notified of any 

incidents that are close to an offender’s 

tracks in time and space. The features are 

accessible through an online mapping 

application, and analysts can review a 

parolee’s GPS data for up to 4 hours at a 

time, or view data in real time (with a 15-

minute delay). 

Keeping track of parolees’ movements can 

take a lot of time and law enforcement 

resources. Law enforcement and parole 

agencies need a way to sum vast amounts 

of spatial behavior and coordinate it with 

related crime information. Environmental 

Systems Research Institute's (ESRI) 

Modelbuilder and the kernel density tool are 

essential for analysts who track and analyze 

sex offender movement data. 

GPS Monitoring Makes 

Parolees Accountable for 

Their Actions 

Both parolees and officers are accountable 

for making sure the parolees meet the 

conditions of parole. Parolees must charge 

the anklet twice a day, and parole agents 

must respond to notifications if the parolee 

enters or leaves an inclusion zone during the 

prescribed times. Furthermore, the parole 

agent must keep track of a parolee’s location 

in relation to new crimes and discuss any 

possible infractions with the parolee. This 

keeps the parolee notified that his or her 

movements are being watched. Although 

real-time monitoring does not allow 

law enforcement to apprehend a parolee 

about to commit a felony, officers must be 

accountable for post-processing the data and 

hold an offender accountable for his or her 

location at all times. 

Finding a Way to Process 

the Data 

When monitoring sex offenders, local law 

enforcement and regional parole officers 

need a method to sum enormous amounts 

of spatial information. Querying 4 hours 

for a single parolee will yield approximately 

240 GPS coordinates, and the server can 

take up to 15 minutes to process this query. 

Reviewing a parolee’s movements for a 

24-hour period produces 1,440 discrete 

recorded locations, and most parole agents 

have a caseload of 20 parolees. The data 

quickly become overwhelming, and it can 

be a challenge to determine which locations 

matter.

Agents currently determine which 

locations to discuss with parolees by 

using a disciplined process of watching 

an individual’s movements and inferring 

behavior. The process of watching an 

individual’s tracks and recording routine 

locations or “anchor points” is time 

intensive. Geographic information systems 

(GIS) can help automate this process.

Each anchor point looks like a cluster of 

points on a map. GPS point data have 

time stamps1

 that indicate that the cluster 

covers roughly the same period of time. 

The cluster’s time stamp also could reveal 

that the points have left and returned (e.g., 

when an offender travels between home 

and work). When analyzing a cluster, the 

size and GPS driftmatter. Analysts should 

determine how best to discern offender 

activity and at what distance clusters should 

remain separate. If the parolee is in the same 

area for 15 minutes or more, that location 

needs to be made an anchor point.

Using the GIS Kernel Density 

Tool to Identify Anchor Points 

The GIS kernel density tool, adapted from 

ecological studies that tracked animals, 

is regularly used for hot spot mapping. 

Crime analysts use the kernel density tool 

to visualize and define groups of crime, 

such as hot spots of violent crime. The GPS 

data are precise and dense enough that the 

search radius of the kernel density does 

not need to be as large for crime events. A 

100-foot search radius is ideal, and a 20-

foot grid cell size supports the small search 

radius. Tiny “home ranges” are translated 

to the centroids2

 of the hot spot, and these 

locations become anchor points merged 

with a larger set of anchor points for that 

parolee. 

When loading GPS data into the kernel 

density tool, analysts should consider time 

range and amount of data. A time range of 

1 to 14 days is possible, and each period 

produces similar results. Some clusters will 

be denser, given more time and GPS point 

data, but the centroid will still be roughly 

the same. A longer period of time will define 

more anchor points, but if the analysis 

process becomes automated and iterative, 

each new day of data will be incorporated 

into the ongoing anchor point database. 

Using ESRI’s Modelbuilder 

for Anchor Point Analysis 

ESRI’s Modelbuilder is essential for 

analyzing sex offender anchor points. 

Running the model for the anchor point 

process can take several minutes. The 

model should be scalable, so that it could 

potentially be run for all tracked offenders. 

Once the model has been created, the 

process is run repeatedly for thousands of 

Determining Anchor Points for Sex Offenders 

Using GPS Data

Philip D. Mielke

Redlands Police Department

Redlands, California

TECHINCAL TIPS
1010

G&PS | May 2009

tracked offenders and anchor point databases 

will continue to grow. 

The geoprocessing steps involved are as follows:

1. Query a day of GPS data for a single 

offender (see Figure 1).

2. Run a kernel density tool with a 100-foot 

search radius and 20-foot grid cells (see 

Figure 2).

3. Reclassify the resulting raster (i.e., grid) to 

give two values (a hot spot = 1, not a hot 

spot = 0).

4. Convert the raster to a polygon.

5. Query the polygon for a hot spot value of 1.

6. Extract the centroids from the hot spot 

(see Figure 3).

After the analyst has determined the centroid, 

the resulting set of anchor point features are 

merged to the previous set for each parolee. 

The analyst may wish to use a data-mining 

procedure to sum the time ranges spent at an 

anchor point to review offender patterns. This 

procedure is complicated by the likelihood 

of the parolee having left and returned to a 

location.

Why Anchor Points Work 

Anchor points can drive tracking analysis and 

serve as points of communication between 

local law enforcement and regional parole 

offices. When an offender is in the vicinity of a 

crime, parole agents and crime analysts receive 

incident hit notification e-mails, which might 

say, for example, “A parolee tracked by the 

system is within 1,500 yards and 30 minutes 

of a time-stamped crime incident.” Most of the 

correlations will be false, so a parole agent or 

crime analyst must prioritize which reports are 

worth investigating. The parole agent can then 

ask the parolee about specific locations that are 

a high priority and present results to local law 

enforcement. Local law enforcement, in turn, 

can flag specific anchor points about which a 

parole agent could question assigned offenders. 

Local law enforcement crime analysts and state 

corrections programs must work together to 

monitor sex offenders and ensure that they 

do not violate parole conditions or recidivate. 

Law enforcement in California must send 

incident data involving sex offenders to the 

CDCR in a timely matter to make crime 

correlation possible. Furthermore, using GIS 

to monitor sex offenders is helpful because 

local law enforcement has a vested interest 

in understanding and updating the changing 

local geography. Regional parole offices have a 

vested interest in monitoring parolee’s spatial 

behavior, and local law enforcement agencies 

are interested in keeping their jurisdictions 

safe. Geographic information systems provide 

the best possible medium for this type of 

communication between local law enforcement 

and regional parole offices.

Notes

1

A time stamp records the date and time that the GPS 

point was recorded.

2

A centroid is the center of a polygon.

Figure 1. A day of GPS tracks from a single 

offender.

Figure 2. Kernel density at 100 feet.

Figure 3. The triangle marks the centroid 

of the hot spot.
11

States across the country have been adopting 

residency restriction laws to keep sex 

offenders away from children, but recent 

geographic research from a special journal 

edition of Criminal Justice Policy Review

suggests these laws may do more harm 

than good.1 Although restrictions keep sex 

offenders away from schools, playgrounds, 

and day care facilities, theoretically 

they make little sense because they limit 

residence locations so severely that they 

force offenders to move to places where 

they cannot get jobs, find acceptable places 

to live, reach treatment programs, or gain 

the basic necessities they need for a healthy 

reentry. 

In 1996, Alabama became the first state 

to restrict where sex offenders could live. 

As of 2008, 29 other states and hundreds 

of localities had followed suit.2 Laws often 

establish buffer zones of between 1,000 and 

2,500 feet around schools, parks, day cares, 

and other places where children congregate, 

and sex offenders cannot live in these areas.

These large buffers take up a lot of 

residential space and leave few places for 

sex offenders to live, meaning that sex 

offenders may be forced to live in rural or 

socially disorganized neighborhoods. A 

number of geographically based studies have 

recently helped shed light on what kind 

of environments are available and why sex 

offenders may not fare well in these areas. 

Restrictions Are not 

Supported by Crime Theory 

Theorists and researchers have a number 

of insights into why sex offenses occur, 

and why residency restrictions make little 

sense. Research indicates no relationship 

between sex offending and residential 

proximity to locations where children 

congregate. Offenders pick their residence 

by what they can afford, and generally find 

victims through a child’s family member or 

acquaintance, or victimize children in their 

own family. 

Even if sex offenders live near schools or day 

care facilities, routine activity theory posits 

that a crime occurs only when a motivated 

offender finds a target who is not cared for 

by a capable guardian. Schools, parks, and 

day care centers generally have numerous 

capable guardians, so offenses are unlikely to 

occur in those settings. 

Additionally, when sex offenders are 

restricted from these areas, they are also 

forced to live far from jobs, treatment 

services, and basic necessities, which make 

the reentry process more difficult. Research 

shows that many find themselves living in 

rural areas or neighborhoods that have high 

levels of social disorganization—meaning 

greater economic disadvantage, lower social 

cohesion, and greater residential mobility. 

These neighborhoods often cannot afford 

the social services that offenders need. 

Without treatment, offenders are more 

likely to commit new crimes.

Also, offenders can become frustrated 

and angry when they believe that their 

punishment is excessive or unfair. Carrie 

Mulford, Ronald Wilson, and Angela Moore 

Parmley conjecture that strain theory may 

explain this idea—if offenders feel they are 

being punished more than a crime warrants, 

it may cause undue stress and lead to 

reoffending. Offenders’ stress levels increase 

when forced to live in disadvantaged 

communities, denied opportunities to 

engage in everyday activities, and cannot 

access treatment or gain employment. 

Consequently, they may recidivate. 

Geographic Analysis Shows 

how Restrictions can Hamper 

Offenders’ Recovery 

The use of geographic information systems 

(GIS) and spatial analysis has helped 

researchers provide visual and statistical 

information about the problems with 

residency restrictions. These geographic 

analysis tools allow geographers to create 

accurate maps of human behavior and 

analyze databases of location information 

with statistical software. Recent analyses 

of residency restrictions have shown 

their potential effects on offenders and 

communities and may help inform better 

policy decisions.

In 2006, Paul Zandbergen and Timothy 

Hart, of the Universities of New Mexico 

and Nevada, used GIS to show that 

expanding a buffer to 2,500 feet would leave 

only 29 percent of all properties available 

for sex offender residence in Orange 

County, Florida.3

 If bus stops were also 

included in the buffer, less than 5 percent 

of properties would be available. A related 

study of potential restrictions in New 

Jersey suggested that residency restrictions 

of 2,500 feet would leave only 54 percent 

of rural territory, 37 percent of suburban 

territory, and 7 percent of urban territory 

available for offender residence. If enacted, 

almost all offenders would need to relocate.4 

But more important than the effect of 

these restrictions on current relocation is 

the distance that offenders would be forced 

to live from social service programs. Sex 

offenders recidivate at lower rates when 

they receive treatment. Geographic studies 

suggest that if residency restrictions remain 

in place, the effects may be costly for 

society. A South Carolina study showed 

that offenders with 2,500-foot buffer zones 

would have to live farther from treatment 

centers. This means they may not receive 

necessary treatment, may have more trouble 

with reentry, may recidivate, and may cause 

strife in their communities.5

The papers in this special journal edition6

demonstrate just how vital studying the 

effects of residency restrictions can be when 

Geographic Research Suggests Sex 

Offender Residency Laws May Not Work

Ron Wilson 

Mapping and Analysis for Public Safety Program and Data Resources 

National Institute of Justice
1212

G&PS | May 2009

NEWS BRIEFS

determining whether new laws and policies 

are a good idea. Police Chief Tom Casady of 

Lincoln, Nebraska, says that policymakers will 

not repeal or defeat residency restrictions unless 

the message is recast by focusing on how these 

laws make neighborhoods less safe. Future 

geographic studies will give these dissenting 

voices the statistics they need to show the longterm consequences of these restrictions and the 

harm they may cause communities.

This news article is based on the following editorial in 

Criminal Justice Policy Review:

Mulford, C.F., R.E. Wilson, and A.M. Parmley. “The 

Geographical Aspects of Sex Offender Residency 

Restrictions: An Introduction to a Special Edition of 

Criminal Justice Policy Review.” Criminal Justice Policy 

Review 20(1)(2009): 3–12

Notes

1

For more information, see: Mulford, C.F., R.E. Wilson, 

and A.M. Parmley. “The Geographical Aspects of Sex 

Offender Residency Restrictions: An Introduction to 

a Special Edition of Criminal Justice Policy Review.” 

Criminal Justice Policy Review 20(2009): 3–12.

2

Meloy, M., S. Miller, and K. Curtis. “Making Sense 

Out of Nonsense: The Deconstruction of State-Level 

Sex Offender Residence Restrictions.” American Journal 

of Criminal Justice 33(2)(2008): 209–222.

3

Zandbergen, P.A. and T.C. Hart. “Reducing Housing 

Options for Convicted Sex Offenders: Investigating 

the Impact of Residency Restrictions Laws Using GIS.” 

Justice Research and Policy 8(2006): 1–24.

4

Chajewski, M. and C. Mercado. “An Evaluation of Sex 

Offender Residency Restriction Functioning in Town, 

County, and City-Wide Jurisdictions.” Criminal Justice 

Policy Review 20(1)(2009): 44–61.

5

Barnes, J.C., T. Dukes, R. Tewksbury, and T.M. 

DeTroye. “Analyzing the Impact of Residency 

Restriction Zones on South Carolina Sex Offenders.” 

Criminal Justice Policy Review, forthcoming.

6

For more information, see: Mulford, C.F., R.E. Wilson, 

and A.M. Parmley. “The Geographical Aspects of Sex 

Offender Residency Restrictions: An Introduction to 

a Special Edition of Criminal Justice Policy Review.” 

Criminal Justice Policy Review 20(2009): 3–12.

Residency restriction laws can severely limit 

sex offenders’ ability to find places to live and 

may endanger communities because they make 

offenders more difficult to monitor.

By 2007, 27 states had passed laws prohibiting 

sex offenders from living near areas where 

children congregate—parks, schools, 

playgrounds, or day care facilities. These laws 

were enacted to protect children from sexual 

predators by reducing offenders’ potential 

access to victims. But recent research that uses 

geographic information systems (GIS) suggests 

that these restrictions make finding housing 

exceptionally difficult for parolees, and may 

encourage them to report false addresses and 

avoid monitoring.

The National Institute of Justice funded 

studies in New Jersey, California, and Ohio that 

used GIS mapping to look at how residency 

restrictions would affect housing. In all 

locations, both rural and urban, they found that 

the availability of legal residences were severely 

limited. Often, offenders would be forced to live 

in uninhabited rural countryside, high-crime 

urban areas, business and commercial districts, 

or other locations with few housing options.

Where in theory residency restrictions may 

appear to limit the possibility of recidivism, in 

reality they often cause offenders to report false 

addresses, become homeless, go underground, 

and escape monitoring. Researchers suggest 

that communities may wish to consider 

alternative ways to keep sex offenders from 

recidivating. 

For more information, see: www.thefreelibrary.

com/Unintended+consequences+of+sex+offend

er+residency+laws:+can+GIS...-a0183302027.

GIS Mapping Shows 

Residency Restrictions Limit 

Offender Housing Options 
13

California Cuts 

Back on Funding 

for Sex Offender 

Housing

California stopped paying to house 

thousands of paroled sex offenders in midFebruary 2009, according to orders from 

corrections officials. 

California paid more than $20 million a 

month to house sex offenders in lieu of 

Proposition 83, a law that bans them from 

living within 2,000 feet of playgrounds 

or parks where children congregate. Some 

parolees have depended on these funds for 

more than 2 years. The new corrections 

order gives them a 60-day transition period 

before they are required to be self-sufficient. 

Critics of Proposition 83 suggest that the 

money would be better spent by removing 

the 2,000-foot residency restriction and 

using the funds to help parolees make the 

transition back into society. Funds used 

to pay for housing for sex offenders might 

be better spent on job training, treatment 

programs, and personal aid. 

For more information, see: www.

mercurynews.com/breakingnews/

ci_11665421?nclick_check=1.

Should Sex 

Offenders 

Have Rights? 

Proposed sex offender restriction laws 

in Illinois to monitor offenders by using 

GPS are meeting with some opposition. 

Although some restrictions make sense, such 

as banning offenders from jobs where they 

have direct contact with children, other 

restrictions, like GPS monitoring, can be 

expensive and do not statistically reduce the 

number of offenses. 

New suggested restrictions include banning 

offenders from Internet dating sites, 

nursing homes, and parts of public libraries. 

Editors of the Illinois State University’s 

Daily Vidette suggest that these restrictions 

may be unconstitutional because they take 

away offenders’ civil liberties. They argue 

that sex crimes vary widely and should be 

approached on a case-by-case basis rather 

than through a statewide law or mandate. 

For more information, see: media.www.

dailyvidette.com/media/storage/paper420/

news/2009/03/02/Editorials/Do.Sex.

Offenders.Have.Rights-3654260.shtml.

Manitowoc 

Defeats Residency 

Restriction 

Proposal 

The Manitowoc, Wisconsin, city council 

failed to pass a recent proposal to keep sex 

offenders from living within 2,000 feet of 

certain areas where children commonly 

congregate. The ordinance failed to pass 

because council members said that they had 

no proof these measures would actually keep 

children safer.

Council alderman Rick Sieracki told the 

local newspaper, the Herald Times, that he 

thought passing the ordinance would have 

done more harm than good. “I can’t believe 

anyone would vote for this. All the groups 

have said the same thing,” he said, “If we’re 

creating safe zones then we’re creating 

danger zones. Our energy would be better 

spent on promoting safe behaviors.”

Sieracki was not alone in his opinion. 

Only one member of the committee 

voted in favor of the new residency 

restrictions. The committee’s chairman 

said the council would prefer to focus on 

notifying community members about a sex 

offender’s presence in their neighborhood 

and educating communities about safety 

hazards.

For more information, see: www.

htrnews.com/article/20090219/

MAN0101/902190380/1358/MAN01.

Tulsa Sex 

Offenders Move 

to the Country

A recent analysis of Oklahoma State 

Department of Corrections data suggests 

that sex offenders who once lived in Tulsa 

are moving to rural communities or going 

underground. These changes are the result 

of city residence restrictions that severely 

limit urban areas where offenders can live.

Since 2005, when residency restriction laws 

took effect, the number of sex offenders 

living in Tulsa has dropped from 600 to 

about 350. In contrast, the number of 

sex offenders in neighboring counties has 

increased significantly.

For more information, see: www.ktul.com/

news/stories/0209/597353.html.
1414

G&PS | May 2009

1. Chajewski, M. and C. Calkins Mercado. 

“An Evaluation of Sex Offender Residency 

Restriction Functioning in Town, County, 

and City-Wide Jurisdictions.” Criminal 

Justice Policy Review 20(1)(March 2009): 

44–61.

2. Chajewski, M. and C. Calkins Mercado. 

“A Geo-Spatial Analysis of Sex Offender 

Residency Restrictions in the State of 

New Jersey.” New York: John Jay College 

of Criminal Justice, March 2007. Paper 

presented at Ninth Crime Mapping 

Research Conference sponsored by 

National Institute of Justice, Pittsburgh, 

Pennsylvania: March 28–31, 2007.

3. Duwe, G., W. Donnay, and R. Tewksbury. 

“Does Residential Proximity Matter? 

A Geographic Analysis of Sex Offense 

Recidivism.” Criminal Justice and Behavior

35(4)(2008): 484–504.

4. Grubesic, T.H., E. Mack, and A.T. Murray. 

“Geographic Exclusion: Spatial Analysis 

for Evaluating the Implications of Megan’s 

Law. “Social Science Computer Review 25(2)

(2007): 143–162.

5. Hughes, L.A. and K.B. Burchfield. “Sex 

Offender Residence Restrictions in Chicago: 

An Environmental Injustice?” Justice 

Quarterly 25(4)(December 2008): 647–673.

6. Levenson, J. and L. Cotter. “The Impact 

of Sex Offender Residence Restrictions: 

1,000 Feet from Danger or One Step from 

Absurd?” International Journal of Offender 

Therapy and Comparative Criminology

49(2)(2005): 168–178.

7. Lindon, L. and J. Rockoff. There Goes the 

Neighborhood? Estimates of the Impact of 

Crime Risk on Property Values from Megan’s 

Laws. Cambridge, Massachusetts: National 

Bureau of Economic Research, Working 

Paper, May 2006.

8. Mustaine, E.E., R. Tewksbury, and 

K.M. Stengel. “Social Disorganization 

and Residential Locations of Registered 

Sex Offenders: Is This a Collateral 

Consequence?” Deviant Behavior 27(3)

(2006): 329–350.

9. Praveen, Maghelal and Miriam Olivares. 

“Critical Risk Zones: Violators of Megan’s 

Law.” ESRI UC Paper Presentation 

at Texas A & M University. www.

proceedings.esri.com/library/userconf/

proc05/papers/pap2035.pdf. 

10. Urban and Regional Information Systems 

Association. Where Are They? A Spatial 

Inquiry of Sex Offenders in Brazos County. 

August 30, 2006. www.urisa.org/pm_

anonymous.

11. Walker, J.T. “Eliminate Residency 

Restrictions for Sex Offenders.” 

Criminology and Public Policy 6(4)(2007): 

863–870.

12. Walker, J.T., J.W. Golden, and A.C. 

VanHouten. “The Geographical Link 

between Sex Offenders and Potential 

Victims: A Routine Activities Approach.” 

Justice Research and Policy 3(2)(2001): 

15–33.

13. Zandbergen, P.A. and T.C. Hart. Reducing 

Housing Options for Convicted Sex 

Offenders: Investigating the Impact of 

Residency Restriction Laws Using GIS. 

Justice Research and Policy 8(2006): 1–24.

Other Resources 

1. The National Sex Offender Public Registry 

web site hosts public sexual offender 

registries. For more information, see 

www.fbi.gov/hq/cid/cac/registry.htm.

2. The National Institute of Justice’s Electronic 

Monitoring Resource Center helps law 

enforcement and corrections agencies 

develop and maintain electronic monitoring 

programs. For more information, see: www.

emresourcecenter.nlectc.du.edu. 

3. The Office of Justice Programs’ Office of 

Sex Offender Sentencing, Monitoring, 

Apprehending, Registering, and Tracking 

(SMART) helps register, track, and monitor 

sex offenders. For more information, see: 

www.ojp.usdoj.gov/smart.

Resources: Geography and Sex Offender 

Residency Restrictions

Related Articles 
15

Geography and Public Safety Events

Dealing with crime problems in a local law enforcement agency sometimes means reaching out to other local 

agencies to come up with a solution. The events listed here are good opportunities to learn what mapping 

professionals and those in related areas are doing, get new ideas, and present your work. 

NGIS 19th Annual Conference

May 18–20, 2009

in Reno, Nevada

www.ngis.org/portal/index.php?option=com_

wrapper&Itemid=77

Pennsylvania GIS Conference 2009

May 19–20, 2009 

in Grantville, Pennsylvania

www.pagisconference.org/

Where 2.0 Conference 2009

May 19–21, 2009 in San Jose, California

en.oreilly.com/where2009

17th Annual Meeting of the Society for 

Prevention Research 

May 26–29, 2009 

in Washington, D.C.

www.preventionresearch.org/meeting.php

GEOTEC Event 2009

June 1–4, 2009 

in Vancouver, British Columbia, Canada

www.geoplace.com/ME2/dirmod.asp?sid=F1E958EC

B4E84C1C97324D4851580DDB&type=gen&mod=C

ore+Pages&gid=104ED2C8722E405C96D6F8344676

7961

2009 ESRI International User Conference

July 13–17, 2009 

in San Diego, California

www.esri.com/events/uc/index.html

The International Conference on Geoinformatics

August 12–14, 2009

in Fairfax, Virginia

www.geoinformatics2009.org

Tenth Crime Mapping Research Conference

August 19–22, 2009 

in New Orleans, Louisiana

www.ojp.usdoj.gov/nij/maps

GIS in the Rockies

September 16–18, 2009 

in Loveland, Colorado

www.gisintherockies.org

2009 National States Geographic Information 

Council (NSGIC) Annual Conference

October 4–8, 2009 

in Cleveland, Ohio

www.nsgic.org/index.cfm

Location Intelligence Conference

October 5–7, 2009

in Westminster, Colorado

www.locationintelligence.net/index.php

GEOINT 2009

October 18–21, 2009 

in San Antonio, Texas

www.geoint2009.com/

2009 Applied Geography Conference

October 28–30, 2009

in Baton Rouge, Louisiana

www.applied.geog.kent.edu

2009 American Society of Criminology 

Annual Meeting

November 4–7, 2009

in Philadelphia, Pennsylvania

www.asc41.com/annualmeeting.htm
U.S. Department of Justice

Office of Community Oriented Policing Services

1100 Vermont Avenue, N.W.

Washington, DC 20530

To obtain details on COPS programs, call the 

COPS Office Response Center at 800.421.6770

Visit COPS Online at www.cops.usdoj.gov

COPS Editorial Staff 

Nicole Scalisi

Social Science Analyst

Office of Community Oriented Policing Services

Judith Beres

Editor

Office of Community Oriented Policing Services

Sandra Sharpe

Graphic Designer

Office of Community Oriented Policing Services

MAPS Editorial Staff 

Ron Wilson

Program Manager/Social Science Analyst 

National Institute of Justice

Timothy Brown

Research Associate (Contractor)

National Institute of Justice

Ariel Whitworth

Communications Editor

National Criminal Justice Reference Service

e050919205

Visit NIJ Online at www.ojp.usdoj.gov/nij

The opinions, findings, conclusions, or recommendations contained in this publication are those of 

the authors and do not necessarily represent the official position or policies of the U.S Department 

of Justice. References to specific agencies, companies, products, or services should not be 

considered an endorsement by the authors or the U.S. Department of Justice. Rather, the references 

are illustrations to supplement discussion of the issues.