FRAGSTATS accepts raster images in a variety of formats, including Geotiff (preferred format), raw ASCII, and raw 8-, 16-, and 32-bit BINARY. Note, FRAGSTATS does not accept vector coverages. All input data formats have the following common requirements:
- All input grids should be signed integer grids (i.e., each cell should be assigned an integer value corresponding to its class membership or patch type). Note, assigning the zero value to a class may cause problems when the landscape contains a border because zero cannot be negative (i.e., all border cells are negative integers).
- All input grids must consist of square cells with cell size specified in meters. For certain input formats (ASCII and BINARY), this is not an issue because cells are assumed to be square and you are required to enter the cell size (in meters) in the graphical user interface. FRAGSTATS assumes that Geotiff's include header information that defines cell size. Consequently these images must have a metric projection (e.g., UTM) to ensure that cell size is given in metric units.
- All input grids must have a cell size > 0.001 m.
There are some additional special considerations for each input data format, as follows:
- Geotiffs -- Geotiff (*.tif or *.tiff) is the recommended format for the input data format (and is the development format). The Geotiff must be projected with a metric projection (e.g., UTM) such that the cell units are in meters.
- Raw ASCII file, no header -- Each record should contain 1 image row. Cell values should be separated by a comma or a space(s). Note, it will be necessary to strip (delete) the header information from the image file if it exists, but be sure to keep it for later reference regarding background cell value, # rows, # columns, cell size, and nodata value.
- Raw 8-, 16-, or 32-bit binary file, no header -- The only limitation on 8- and 16-bit binary files is that they are not suitable for moving window analysis, which requires the output grids to be floating points (32 bit files). Note, it will be necessary to strip (delete) the header information from the image file if it exists, but be sure to keep it for later reference regarding background cell value, # rows, # columns, cell size, and nodata value.