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FRAGSTATS: Spatial Pattern Analysis Program for Categorical Maps

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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 popularity, the program was completely revamped in 2002 (version 3). Recently, the program was upgraded to accommodate ArcGIS10 (version 3.4). The latest release (version 4) reflects a major revamping of the software, with a completely redesigned architecture intended to support the addition of cell-level metrics and surface pattern metrics, among other things. The current release of version 4 (v4.2) has essentially the same functionality as version 3, but with a new user interface that reflects the redesign of the model architecture, support for additional image formats, and a variety of sampling methods for analyzing sub-landscapes.

The purpose of this web site is to facilitate dissemination of the software and to facilitate communication among FRAGSTATS users.

About The Developers

The original version of FRAGSTATS (v2), published in 1995, was developed by Dr. McGarigal and Barbara Marks of Oregon State University. Ms. Marks was the programmer and primary technical support person for the original release.

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. Eduard Ene, an independent consultant and associate of the UMass Landscape Ecology Lab, is now the principal programmer. Dr. Sam Cushman and Dr. Maile Neel provided valuable input during the development and testing of version 3.

Version 4 is currently the development version and is being developed and supported by Dr. McGarigal and Dr. Cushman with programming by Eduard Ene.

Dr. McGarigal is the primary contact person for questions and comments regarding all versions of FRAGSTATS.

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 slide presentations from prior workshops.
  • Downloads -- This page is where you go to download the software and documentation.
  • 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.
  • Workshops -- This page contains links to workshop materials for any upcoming scheduled workshop.

What's In Version 4?

Version 4 is a stand-alone program written in Microsoft Visual C++ for use in the Windows Operating environment. It accepts raster images in a variety of formats, including ASCII grid, 8-, 16- and 32-bit integer grids, ESRI grid (or raster), GeoTIFF grid, VTP binary terrain format grid, ESRI header labelled grid, ERDAS Imagine grid, PCRaster grid, and SAGA GIS binary format grid. Support for the latter six image formats is via the GDAL library. Some of the key features of version 4 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.
  • Command line execution.--FRAGSTATS can be executed from a command line to allow for execution from within another program (as an external execution)
  • Patch-based metrics.--FRAGSTATS computes numerous metrics that describe the structure of individual patches, classes or collections of patches of the same type, and the entire landscape mosaic for categorical patch mosaics.
  • Cell-based metrics.--FRAGSTATS (scheduled for inclusion in version 4.3) will compute a variety of cell-based metrics that describe the spatial structure of the local neighborhood of individual cells without regard to patch membership.
  • Surface metrics.--FRAGSTATS (scheduled for inclusion in version 4.4) will compute a variety of surface metrics that describe the spatial structure of continuous surfaces (i.e., landscape gradients).
  • Structural and functional metrics.-- FRAGSTATS computes a large number of structural metrics that depend only on the physical structure of the landscape, in addition to many different functional metrics that must be parameterized by the user uniquely for each application to reflect the phenomenon under consideration. Functional metrics include measures of core area (that account for depth-of-edge effects), edge contrast (that account for the magnitude of difference between adjacent patch types), and isolation (that account for ecological neighborhood size and similarity between different patch types).
  • Batch processing.--FRAGSTATS allows batch files comprised of multiple input grids (optionally in different formats) to be processed with a single execution.
  • Sampling strategies.--FRAGSTATS provides several options for sampling the landscape to analyze sub-landscapes, including exhaustive sampling involving either user-provided tiles (sub-landscapes), uniform tiles, or moving windows (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) and partial sampling involving either user-provided focal points (in grid or table format) or randomly generated focal points in which a window (sub-landscape) of specified size and shape is placed over each point. These sampling options essentially facilitate batch processing of multiple landscapes or sub-landscapes that was previously required to be generated outside of FRAGSTATS using a GIS.
  • Nodata, background & border.--FRAGSTATS provides options for the specification and handling of nodata (unclassified cells), background (classified, but annoymous) and border (buffer of classified cells outside the designated landscape boundary.


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), University of Massachusetts-produced program (version 3), or LandEco Consulting (Dr. McGarigal, sole propeitor) and University of Massachusetts-produced program (vesion 4). 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 aware of 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 and it can do so very easily and quickly. 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 you have read the entire documentation. This is only fair and will eliminate many trivial questions. Fiinally, 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.


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. Funding for the ongoing development of version 4 is provided by LandEco Consulting and the USDA Forest Service, Rocky Mountain Research Station.


At this time we do not have a technical report with a proper citation for the current version of FRAGSTATS. Until a general techical report is published, this website is the sole means of "publication" of the software. We suggest the following citation:

Version 4:

McGarigal, K., SA Cushman, and E Ene. 2012. FRAGSTATS v4: Spatial Pattern Analysis Program for Categorical and Continuous Maps. Computer software program produced by the authors at the University of Massachusetts, Amherst. Available at the following web site:

Version 3:

McGarigal, K., SA Cushman, MC Neel, and E Ene. 2002. FRAGSTATS v3: 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:

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

Copyright 2000 University of Massachusetts Amherst, Massachusetts, 01003. (413) 545-0111. This is an official page of the University of Massachusetts Amherst campus. All material in this website is made available according to the Fair Use Statute of the U.S. Copyright Act