Fragstats Home Page

FRAGSTATS

Spatial Pattern Analysis Program for Categorical Maps

Welcome To FRAGSTATS!

FRAGSTATS is a computer software program designed to compute a wide variety of landscape metrics for categorical map patterns.The original software (version 2) was released in the public domain during 1995 in association with the publication of a USDA Forest Service General Technical Report (McGarigal and Marks 1995).

Since then, hundreds of professionals have enjoyed the use of FRAGSTATS. Due to its growing popularity, we have completely revamped the program. The purpose of this web site is to facilitate dissemination of the new software (version 3) and to facilitate communication among FRAGSTATS users.

About the Authors

The original version of FRAGSTATS, published in 1995, was developed by Dr. Kevin McGarigal and Barbara Marks of Oregon State University. Ms. Marks was the programmer and primary technical support person for the original release. She now works for Hewlett Packard and no longer provides technical support.

The current version (3) was developed by Dr. Kevin McGarigal with programming by Eduard Ene and additional programming assistance by Chris Holmes. Chris Holmes was responsible for the initial reprogramming. He now works for Compaq Computers. Eduard Ene, a research assistant at the University of Massachusetts, is now the principal programmer. Dr. McGarigal continues to be the principal developer of FRAGSTATS and is the primary contact person for questions and comments.

What's in This Website

This web site is logically organized into the following pages:

FRAGSTATS Documentation -- This page contains links to all FRAGSTATS documentation, including background material, user guidelines, and a description of the metrics.
Downloads -- This page is where you go to download the software and documentation. The original FRAGSTATS (version 2) and the new release (version 3), as well as all future patch updates and releases can be downloaded from this page.
FAQ -- This page contains answers to frequently asked questions, including questions and answers extracted from the FRAGSTATS list serve that warrant permanent posting.
Links -- This page contains links to other web sites containing information on related software.

FRAGSTATS Users Group

If you have questions about FRAGSTATS or are seeking advice on a FRAGSTATS-related problem, then the FRAGSTATS list serve is the place to go. This list serve is designed to facilitate communication, problem-solving, and idea-sharing among FRAGSTATS users on issues dealing with landscape metrics and the analysis of landscape pattern. In addition, all patches and releases of new versions will be announced via this list serve. To join this list serve, simply send an email to the following address requesting that you be added to the list: fragstats-request@forwild.umass.edu

What's New in Version 3?

The major difference between version 2 and 3 is the addition of a graphical user interface to facilitate the parameterization of FRAGSTATS, and the addition of several new landscape metrics and analysis capabilities. Like version 2, version 3 accepts input images in a variety of formats (e.g., Arc Grid, Ascii, ERDAS, EDRISI, Binary); however, version 3 is limited to raster formats only. Because of this difference, version 2 still has utility for users that require or prefer to use vector coverages in Arc/Info. All other users, however, should find version 3 preferable and considerably more powerful. Here are the key distinguishing features of each version:

Version 2:

Two separate versions of FRAGSTATS 2 exist; one that accepts Arc/Info polygon coverages (vector) and one that accepts raster images in a variety of formats. The vector version is an Arc/Info AML developed on a SUN workstation using Arc/Info version 6.1; it will not run with earlier versions of Arc/Info. Because of limitations in Arc/Info, the AML calls several C programs that were developed in a Unix environment and compiled with the GNU C compiler (note, they may not compile with other compilers). The raster version is a stand-alone C program that accepts ASCII image files, 8 or 16 bit BINARY image files, Arc/Info SVF files (which Arc/Info no longer supports), ERDAS image files, and IDRISI image files. The raster version also was developed on a SUN workstation in the Unix operating environment. It is written in C and also compiled with the GNU C compiler. The raster version also has been compiled to run in the DOS environment on a personal computer (PC). The directions for running the DOS version on a PC are exactly the same as the Unix version. Both vector and raster versions respond to command line input or allow the user to answer a series of prompts. Both versions generate the same array of metrics, including a variety of area metrics, patch density, size and variability metrics, edge metrics, shape metrics, core area metrics, diversity metrics, and contagion and interspersion metrics, although a few additional metrics (i.e., nearest-neighbor metrics and contagion) are computed in the raster version. The format of the output files is exactly the same.

Version 3:

Version 3 is a stand-alone program written in Microsoft Visual C++ for use in the Windows Operating environment. Like version 2, it accepts raster images in a variety of formats, including Arc Grid, ASCII, 16 or 32 bit BINARY, ERDAS, and IDRISI image files. Some of the key features that distinguish version 3 from version 2 include:

Graphical User Interface.--FRAGSTATS analyses are parameterized via a graphical user interface which allows the user to tailor each run to their specific needs.
New Landscape Metrics.--Several new metrics have been added.
Nearest Neighbor Distance.--Calculation of nearest neighbor distance are slightly different in version 3 because instead of cell edge-to-edge distance (as in version 2), we now use cell center-to-center distance. We believe that this makes more sense given the way in which raster grids represent real-world edges (i.e., the true edge is as often as not in the center of the grid cell) and overcomes some computational difficulties with indices that use nearest neighbor distance in the denominator (hence eliminating the possibility of having a zero in the denominator).
Core Area.--Core area metrics now allow for user-specified unique edge depths for each unique edge type, instead of requiring a constant edge depth for all edges.
Moving Window Analysis.--A moving window analysis option is provided in which a moving window of specified size and shape is passed over the landscape and returns a value for each selected metric at the class and landscape levels to the focal cell. The result is a new grid for each metric in which the cell values represent the computed metric values. This is a powerful new tool, but comes at the cost of huge computer processing demands.
Background & Border.--Rules regarding the specification and handling of background and border have been modified slightly to achieve greater consistancy and logic.
Command Line Execution.--FRAGSTATS can be executed from a command line to allow for execution from within another program (as an external execution)

Disclaimer

This software is in the public domain, and the recipient may not assert any proprietary rights thereto nor represent it to anyone as other than an Oregon State University-produced program (version 2.0) or University of Massachusetts-produced program (version 3.0). FRAGSTATS is provided "as is" without warranty of any kind, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. The user assumes all responsibility for the accuracy and suitability of this program for a specific application. In no event will the authors or the University be liable for any damages, including lost profits, lost savings, or other incidental or consequential damages arising from the use of or the inability to use this program.

As the authors of FRAGSTATS, we are VERY concerned about the potential for misuse of this program. Like most tools, FRAGSTATS is only as "good" as the user. FRAGSTATS crunches out a lot of numbers about the input landscape. These numbers can easily become "golden" in the hands of uninformed users. Unfortunately, the "garbage in- garbage out" axiom applies here. We have done our best in the documentation to stress the importance of defining the landscape at a scale and in a manner that is relevant and meaningful to the phenomenon under consideration. Moreover, we have stressed the importance of understanding the exact meaning of each metric before it is used. These and other important considerations in any landscape pattern analysis are discussed in the "background material" contained on this web site. We strongly urge you to read the entire documentation before ever running FRAGSTATS.

We wish to remind users that we are not in the commercial software marketing business. We are scientists who recognized the need for a tool like FRAGSTATS to assist us in our research on landscape ecological issues. Therefore, we do not wish to spend a great deal of time consulting on trivial matters concerning the use of FRAGSTATS. However, we do recognize an obligation to provide some level of information support. Of course, we welcome and encourage your criticisms and suggestions about the program at all times. We will welcome questions about how to run FRAGSTATS or interpret the output only after the user has read the entire documentation. This is only fair and will eliminate many trivial questions. In this regard, we encourage you to join the FRAGSTATS list serve and seek assistance from the vast community of users. They are the real experts and the probable source of most answers. Finally, we are always interested in learning about how others have applied FRAGSTATS in ecological investigations and management applications. Therefore, we encourage you to contact us and describe your application after using FRAGSTATS.

We hope that FRAGSTATS is of great assistance in your work and we look forward to hearing about your applications.

Acknowledgements

Many individuals provided valuable feedback during the development and many revisions of the original software (version 2), including Steve Garman, Eric Gustafson, Jeff Nighbert, Tom Moore, Catherine Rogers, and David Wallin. We are especially grateful to Catherine Rogers and Eric Gustafson for their comprehensive and detailed testing of the original program and their many useful suggestions. Initial funding for development of the original software was provided through the Coastal Oregon Productivity Enhancement (COPE) program; COPE is a cooperative research and technology transfer effort among Oregon State University, USDA Forest Service, USDI Bureau of Land Management, other state and federal agencies, forest industry, county governments, and resource protection organizations. Subsequent funding for the completion of the FRAGSTATS 2 documentation (McGarigal and Marks 1995) was provided by the USDI Bureau of Land Management Cooperative Research Unit and the USDA Forest Service, Pacific Northwest Research Station, Corvallis, Oregon. Funding for the development of version 3 was provided by the USDA Forest Service, Rocky Mountain Region, Denver, Colorado and the University of Massachusetts, Amherst. We are especially grateful to Claudia Regan for her support of the project.

How to Cite FRAGSTATS

Unfortunately, we can't provide a proper journal or book citation for the current version of FRAGSTATS. Currently, this website is the sole means of "publication" of the software. We have a FRAGSTATS book in the making, but it will be some time before it is finished. In the meantime, I suggest the following citation:

McGarigal, K., S. A. Cushman, M. C. Neel, and E. Ene. 2002. FRAGSTATS: Spatial Pattern Analysis Program for Categorical Maps. Computer software program produced by the authors at the University of Massachusetts, Amherst. Available at the following web site: www.umass.edu/landeco/research/fragstats/fragstats.html

For more information, please contact:
Dr. Kevin McGarigal
Department of Natural Resources Conservation
University of Massachusetts
304 Holdsworth Natural Resources Center
Box 34210
Amherst, MA 01003
Fax: (413) 545-4358
Phone: (413) 577-0655
Email: mcgarigalk@forwild.umass.edu