Long Term Resource Monitoring Program

Program Report

95-P008-1

Long Term Resource Monitoring Program

Standard Operating Procedures:

Photointerpretation

July 1995
Long Term Resource Monitoring Program

Standard Operating Procedures:

Photointerpretation

by 

Thomas Owens

National Biological Service

Environmental Management Technical Center

575 Lester Avenue

Onalaska, Wisconsin 54650

and

Kevin D. Hop

St. Mary's University of Minnesota

700 Terrace Heights

Winona, MN 55987-1399

July 1995
The Environmental Management Technical Center issues LTRMP Program Reports to

provide Long Term Resource Monitoring Program partners with programmatic documentation,

procedures manuals, training manuals, and geospatial applications.

National Biological Service

Environmental Management

Technical Center

CENTER DIRECTOR

Robert L. Delaney

SCIENCE ADVISOR

John W. Barko

INFORMATION AND TECHNOLOGY

SERVICES DIRECTOR

Norman W. Hildrum

GEOSPATIAL APPLICATIONS

DIRECTOR

Frank D'Erchia

INFORMATION TRANSFER AND MEDIA

SERVICES MANAGER

Terry D'Erchia 

REPORT EDITOR

Madelon M. Wise

Cover Graphic by Mi Ae Lipe-Butterbrodt

Mention of trade names or commercial products does not constitute endorsement or recommendation for

use by the National Biological Service, U.S. Department of the Interior.

The National Biological Service . . . gathering, analyzing,

and sharing the biological information necessary to support the wise

stewardship of the Nation's natural resources.

 Printed on recycled paper 
iii

Preface

The Long Term Resource Monitoring Program (LTRMP) was authorized under the Water Resources

Development Act of 1986 (Public Law 99-662) as an element of the U.S. Army Corps of Engineers'

Environmental Management Program. The LTRMP is being implemented by the Environmental

Management Technical Center, an office of the National Biological Service, in cooperation with the five

Upper Mississippi River System (UMRS) States of Illinois, Iowa, Minnesota, Missouri, and Wisconsin,

with guidance and Program responsibility provided by the U.S. Army Corps of Engineers. The UMRS

encompasses the commercially navigable reaches of the Upper Mississippi River, as well as the Illinois

River and navigable portions of the Kaskaskia, Black, St. Croix, and Minnesota Rivers.

The mission of the LTRMP is to provide decision makers with information to maintain the UMRS as

a sustainable large river ecosystem given its multiple-use character. The long-term goals of the Program

are to understand the system, determine resource trends and impacts, develop management alternatives,

manage information, and develop useful products.

The strategy to develop and adopt standard operating procedures is included in the LTRMP

Operating Plan as Strategy 4.1.1, Develop and Update Information Management Guidance Documents

under Objective 4.1, Provide Direction for Automation Activities. This report was developed with funding

provided by the Long Term Resource Monitoring Program.

Additional copies of this report may be obtained from the National Technical Information Service,

5285 Port Royal Road, Springfield, Virginia 22161 (800/553-6847).

This report should be cited as:

Owens, T., and K. D. Hop. 1995. Long Term Resource Monitoring Program standard operating

procedures: Photointerpretation. National Biological Service, Environmental Management Technical

Center, Onalaska, Wisconsin, July 1995. LTRMP 95-P008-1. 7 pp + Appendixes A and B.
v

Contents

Page

Preface ........................................................................ iii

Contents ....................................................................... v

Introduction ..................................................................... 1

Initial Project Scoping ............................................................. 1

Project Planning .................................................................. 1

Specify Imagery to be Used for Project ............................................ 1

Acquire Imagery ............................................................. 1

Obtain Collateral Data ........................................................ 2

Design and Develop the Classification System ...................................... 2

Prepare a Flightline Index ...................................................... 2

Prepare Photos for Interpretation ................................................ 2

Field Verification ................................................................. 3

Photointerpretation ................................................................ 3

Quality Control .................................................................. 5

References ...................................................................... 6

Appendix A .................................................................... A-1

Appendix B .................................................................... B-1
Introduction

The following general procedures are provided for photointerpretation projects initiated under the

Long Term Resource Monitoring Program (LTRMP). Guidance is provided for acquisition of materials,

classification, photo preparation and interpretation, field work, and quality control. Environmental

Management Technical Center staff should follow these guidelines when planning a photointerpretation

project. LTRMP Field Station staff should follow the procedures specified in the Standard Operating

Procedures for Field Station Photointerpretation (Owens and Hop 1995).

Initial Project Scoping

First, client requirements must be determined. Are needs well defined? Does the client require

assistance in determining the best remote sensing/mapping approach? Some of the following questions may

be relevant: What is the client's objective? What information does the client want? What type of imagery

does the client need—satellite or photography? What type of photography is needed (color, color-infrared,

black-and-white, scale, vintage)? What minimum mapping unit (MMU) does the client require?

1. Determine the best method to meet the client's requirements.

2. Define the study area boundary.

3. Determine data themes to be mapped.

4. Determine project time and make material estimates.

Project Planning

Specify Imagery to be Used for Project

1. Existing imagery: Determine if existing imagery will meet project goals according to scale, date,

film type, etc.

2. New imagery: If existing imagery is not appropriate, develop specifications for obtaining new

imagery (scale, film/filter type, date of imagery, stereo coverage, etc.).

Acquire Imagery

1. Order new or existing imagery.

2. Thoroughly check incoming imagery for the following factors: Color quality, crab or tilt, cloud

cover, scale, overlap, and sufficient coverage.
2

Obtain Collateral Data

1. Obtain topographic base maps from the U.S. Geological Survey at the appropriate scale

(1:24,000, 1:62,500, 1:100,000, or 1:250,000). One clean, unfolded set of maps is needed for

cartography; another set may be required for field use.

2. Determine whether data are necessary and obtain these materials (e.g., field guides to vegetation,

soil surveys, existing maps, etc.).

Design and Develop the Classification System

1. Use a classification system developed by the user, or a standard or national classification system

(e.g., Anderson 1976; Cowardin et al. 1979).

2. If existing classification systems are not suitable, develop a new classification system based on

user needs.

3. Determine the MMU required.

Prepare a Flightline Index

1. If a flightline index does not exist, prepare an index that shows frame numbers and flightlines in

relation to study area and base maps.

2. Organize photographs into folders based on flightlines and project areas. Store maps and other

collateral data neatly in map racks or drawers so that they are easily accessible.

Prepare Photos for Interpretation

1. Place clear acetate overlay, cut to size, on photo and secure with tape on each corner.

2. Mark fiducials and photo numbers on overlay with drafting pen. If the overlay is shifted or

removed, it then can be accurately replaced.

3. Place one photo over an adjacent photo in the flight strip, find the halfway point of the overlap,

and draw a line marking this overlap on the first photo.

4. Using a stereoscope, find matching points along the line drawn on the photos, then connect these

lines with a straight edge.

5. Repeat this process on all sides of each photo with adjacent photos.
3

6. Trace the study area boundary on all photos that cover the outer edge of the study area. 

Continue this process until the entire study area encompassed by the photo overlays is a closed

polygon.

Field Verification

1. A field trip is an expensive and complex endeavor and must be carefully planned. Before leaving

on a field trip, be sure that all materials are in hand (photos, maps, collateral data), local guides

and experts are available (if necessary), and all logistical and transportation problems have been

solved.

2. Scan photographs and locate areas that present questions and are easily accessible by car, boat,

or foot. Also locate all easily accessible major photograph signatures and cover types.

3. Mark potential field sites on a good topographic map. Note pertinent questions and comments

about the sites in the map border.

4. Travel to the site and locate the areas on the ground. A field sheet (Appendix A) is helpful in

prompting the interpreter to ask and answer all pertinent questions. Take careful notes about

each site on the photograph sleeve (using permanent marker) to locate the exact signature and

area. Note such things as size, major species composition and mixture, percentage of each

species, etc., and make good sketch maps. Ground photographs are very helpful in recalling

details about the site once the interpreter is back in the office.

5. Carefully review the field notes and sketch maps to ensure that all initial questions were

answered.

6. If time and money permit, subsequent field trips may be necessary to answer questions that arise

during interpretation.

Photointerpretation

1. Photointerpretation is usually done under a stereoscope with stereo pairs of photos. First, place

the photos under the objective lenses so that the photos are aligned with the flightline, then locate

an obvious feature, such as a road intersection. Look through the stereoscope and align the

photos so all features are focused in the view and topography becomes apparent.

2. Delineate the features of interest described in the classification system. Features are delineated

by identifying signature, the characteristic appearance of an object on a given type of imagery. 

Vegetation signatures vary greatly according to time of day, time of season, type of photography,

and scale, and are affected by the following factors: color/tone, texture, pattern, shape, size, and

location. A single factor may not be sufficient to identify an object, but a combination of these

factors will often lead to proper identification. For example, two vegetation types found in

different locations may have the same color and texture; conversely, two vegetation types found
4

in the same location may have different colors. It is important to learn the combination of factors

that distinguish one type from another.

(a) Color/Tone: Color is the combination of hue, chroma, and saturation in color

photography, while tone is the shade of gray in black-and-white photography. These two

factors usually convey more information to the interpreter than anything else. The human

eye can distinguish 100 to 200 shades of gray, while it can distinguish thousands of

different colors. For these reasons, color and color-infrared photography are far superior

to black-and-white photography in vegetation identification.

(b) Texture: Texture is the composition and arrangement of small constituent parts of an

object. Texture may be characterized by such terms as smooth, uniform, velvety, or rough. 

Planted vegetation usually appears smoother than natural vegetation, while differences in

height produce rougher textures.

(c) Pattern: Pattern or repetition is the characteristic arrangement of objects. Some vegetation

types have highly distinctive patterns that are easily recognized and aid in feature

identification.

(d) Shape: An object's shape may be difficult to recognize from the vertical perspective of

aerial photography. The shape or form of objects may be determined by their shadows. 

For example, tree shadows can be used to determine species.

(e) Size: Some objects are easily identified by their size and can be used as guides to determine

the size of other objects not so easily identified. Relative size may be critical in identifying

objects, such as a shrub versus a tree.

(f) Location: Location covers a wide variety of factors such as global location, ecological

site, and association with other objects.

3. Work methodically from the general to the specific and from the known to the unknown. Begin

interpretation of photographs that have been groundtruthed to get a good grasp of visual clues

and photographic signatures.

4. Delineation and labeling must be done in a neat, legible manner. Lines should be of uniform

width and should closely follow the ground features on the photo. Polygons must be closed and

labels should be placed within the polygon. However, if the polygon is too small, the label

should be placed outside the polygon with a lead-line into the polygon. Linears should be used to

delineate significant ground features that cannot be delineated with a polygon. A linear must be

labeled with an arrow from the label to the linear feature.

5. If a project area is large and requires more than one interpreter, a photointerpretation key may be

necessary to organize and synthesize information. Keys can take many forms, including

dichotomous keys and descriptive keys. A dichotomous key provides a series of choices for the

photointerpreter to work through, as the following example illustrates:
5

(1) Vegetation is found in wetlands, go to 2; or

(1) Vegetation is found in uplands, go to 10.

The next example is a descriptive key which describes the important cover types:

Sagittaria (arrowhead) has a medium pink color, a velvety texture, and is found

in 6 inches to 2 feet of water.

6. After interpreting each photo, match all lines and labels with adjacent photos to ensure that edge

ties and labels are accurate and consistent (including side lap).

7. When interpretation is completed, place a clean sheet of white paper between the overlay and the

photo to check for completeness of linework and labeling as well as interpretation errors.

8. Use a production log to track and record completed work (Appendix B). Logs are essential to

record completed photos, to document problems or concerns, and to track progress.

Quality Control

1. Interpretation will be checked by the supervisor or another experienced photointerpreter who is

familiar with the project. To promote correctness and consistency of work, the basic guideline is

to assume that errors exist and to search for them.

2. Place a sheet of white paper between the overlay and the photo and make sure that lines and

labels are neat, clean, and complete. Check edge ties to adjacent photos.

3. Scan each polygon under the stereoscope to check the correctness of final linework and labels

and the consistency of classification.

4. Sign your initials on the production log when interpretation is complete.
6

References

Anderson, J. R., E. E. Hardy, J. T. Roach, and R. E. Witmer. 1976. A land use and land cover

classification system for use with remote sensor data. Geological Survey Professional Paper 964, U.S.

Geological Survey, Washington, D.C. 28 pp.

Cowardin, L. M., V. Carter, F. C. Golet, and E. T. LaRoe. 1979. Classification of wetlands and

deepwater habitats of the United States. U.S. Fish and Wildlife Service, Office of Biological Services,

Washington, D.C. 131 pp.

Owens, T., and K. D. Hop. 1995. Long Term Resource Monitoring Program standard operating

procedures: Field station photointerpretation. National Biological Service, Environmental

Management Technical Center, Onalaska, Wisconsin, August 1995. LTRMP 95-P008-2. 11 pp. +

Appendixes A-E.

U.S. Fish and Wildlife Service. 1992. Operating Plan for the Upper Mississippi River System Long Term

Resource Monitoring Program. Environmental Management Technical Center, Onalaska, Wisconsin,

Revised September 1993. EMTC 91-P002. 179 pp. (NTIS #PB94-160199)
A-1

Appendix A

Upper Mississippi River System Field Sheet

Reported By_________________________ Date______________ Site No.______________

Other Field Personnel_________________________________________________________

______________________________________________________________________________

General Site Data

Aerial Photo: Number______ Date_________ Type__________________ Scale________

USGS Quad___________________ State_________ City____________________ Pool_____

Township_______________________ Range_______________________ Section__________

Brief description of site relative to identifiable points on top map

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Attach photocopy of field site from 7 1/2" quad

______________________________________________________________________________

Ground Photo Data

Roll Number Direction Description

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________
A-2

Upper Mississippi River Sytem Field Sheet

Detailed Site Data

Description of Site___________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Dominant Plants_______________________________________________________________

______________________________________________________________________________

Common Plants_________________________________________________________________

______________________________________________________________________________

Less Common Plants____________________________________________________________

______________________________________________________________________________

Initial Field Classification (1) Geomorph_____________________________________

2) Land Use/Land Cover________________________________________________________

Discussion of Photo Interpretation____________________________________________

______________________________________________________________________________

______________________________________________________________________________

Final Photo Classification (1) Geomorph_______________________________________

(2) Land Use/Land Cover_______________________________________________________

Soils Data____________________________________________________________________

______________________________________________________________________________

Other Observations (water regime, wildlife, geomorph, etc.) Discussion

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

Sketch of Field Site

Approximate Scale North

Arrow
B-1

Appendix B

Photointerpretation Production Log

Project: Total Number Photos: 

Photo No. Date Time Hours QC Comments Map Name

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________

______________________________________________________________________________
REPORT DOCUMENTATION PAGE Form Approved

OMB No. 0704-0188

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gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this

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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

July 1995

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

Long Term Resource Monitoring Program Standard Operating Procedures: Photinterpretation

6. AUTHOR(S)

Thomas Owens and Kevin D. Hop 1 2

7. PERFORMING ORGANIZATION NAME AND ADDRESS 8. PERFORMING ORGANIZATION

National Biological Service 1

Environmental Management Technical Center

575 Lester Avenue

Onalaska, Wisconsin 54650

St. Mary's University of Minnesota 2

700 Terrace Heights

Winona, Minnesota 55987-1399

 REPORT NUMBER

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING

National Biological Service 

Environmental Management Technical Center 95-P008-1

575 Lester Avenue

Onalaska, Wisconsin 54650

 AGENCY REPORT NUMBER

11. SUPPLEMENTARY NOTES

12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Release unlimited. Available from National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161 

(800/553-6847)

13. ABSTRACT (Maximum 200 words)

Guidance is provided for planning a photointerpretation project, including acquisition of materials, classification, photo preparation and interpretation, field work, and quality

control. The Environmental Management Technical Center should follow these guidelines. The planning process is divided into several steps: (1) initial project scoping, which

includes determining client needs; (2) project planning; (3) acquiring imagery, whether new or existing; (4) obtaining collateral data; (5) adapting a classification system, whether

the system is a new one or existing classification; (6) preparing a flightline index; (7) preparing photos for interpretation; (8) field verification; (9) photointerpretation; and (10)

quality control. Detailed instructions are given for each section. 

14. SUBJECT TERMS 15. NUMBER OF PAGES

Aerial photography, aerial photointerpretation, vegetation mapping 8 pp. + Appendixes A and B

16. PRICE CODE

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT

 OF REPORT OF THIS PAGE OF ABSTRACT

Unclassified Unclassified Unclassified
The Long Term Resource Monitoring Program (LTRMP) for the Upper

Mississippi River System was authorized under the Water Resources

Development Act of 1986 as an element of the Environmental Management

Program. The mission of the LTRMP is to provide river managers with

information to maintain the Upper Mississippi River System as a sustainable

large river ecosystem given its multiple-use character. The LTRMP is a

cooperative effort by the National Biological Service, the U.S. Army Corps of

Engineers, and the States of Illinois, Iowa, Minnesota, Missouri, and Wisconsin.