Output Files

Depending on which metrics are selected by the user, FRAGSTATS creates 4 output files corresponding to the three levels of metrics and the adjacency matrix. The user supplies a "basename" for the output files and FRAGSTATS appends the extensions .patch, .class, .land and .adj to the basename. All files created are comma-delimited ASCII files and viewable. These files are formatted to facilitate input into spreadsheets and database management programs:

•    "basename".patch file.–Contains the patch metrics; the file contains 1 record (row) for each patch in the landscape; columns represent the selected patch metrics. If a batch file is analyzed, the file contains 1 record for each patch in each landscape specified in the batch file. The first record is a column header consisting of the acronyms for all the metrics that follow. For a single landscape, the patch output file would be structured as follows:

            LID,                PID,    TYPE,       AREA,      PERIM,    GYRATE,      CORE

            D:\testgrid,      9,         forest,        1.0000,      400.0000,  38.1195,          0.1600

            D:\testgrid,      0,         shrub,        4.0000,      800.0000,  76.4478,          1.9600

Etc.

•    "basename".class file.–Contains the class metrics; the file contains 1 record (row) for each class in the landscape; columns represent the selected class metrics. If a batch file is analyzed, the file contains 1 record for each class in each landscape specified in the batch file. The first record is a column header consisting of the acronyms for all the metrics that follow. For a single landscape, the class output file would be structured as follows:

            LID,                TYPE,       CA,           PLAND,   NP,     PD,           LPI

            D:\testgrid,      forest,        8.0000,      22.5000,    4,   5.0000,      15.000

            D:\testgrid,      shrub,        21.0000,    26.2500,    3,   3.7500,      12.500

Etc.

•    "basename".land file.–Contains the landscape metrics; the file contains 1 record (row) for the landscape; columns represent the selected landscape metrics. If a batch file is analyzed, the file contains 1 record for each landscape specified in the batch file. The first record is a column header consisting of the acronyms for all the metrics that follow. For a single landscape, the landscape output file would be structured as follows:

            LID,                TA,           NP,     PD,           LPI,           TE,                  ED

            D:\testgrid,      80.0000,    12,       15.0000,    15.0000,    7800.0000,      97.500

•    “basename”.adj file.–Contains the class adjacency matrix; the file contains a simple header in addition to 1 record (row) for each class in the landscape, and is given in the form of a 2-way matrix. Specifically, first record contains the input file name, including the full path. The second record and first column contain the class IDs (i.e., the grid integer values associated with each class), and the elements of the matrix are the tallies of cell adjacencies for each pairwise combination of classes. For a single landscape, the adjacency output file would be structured as follows:

D:\testgrid

            Class ID / ID, 2,         3,          4,        5,         Background

            2,                     6840,   130,     120,     10,       0

            3,                     120,     7960,   160,     40,       10

            4,                     100,     140,     9880,   40,       20

            5,                     10,       40,       30,       3080,   16

Note, the adjacency tallies are generated from the double-count method in which each cell side is counted twice–at least for all positively-valued nonbackground cells–and only the 4 orthogonal neighbors are considered. In addition, the matrix may not be symmetrical if a landscape border is present because landscape boundary edges are only counted once. For example, a cell of class 3 (inside the landscape) adjacent to a cell of class -5 (in the landscape border) results in an adjacency for class 3; specifically, a 3 (row) -5 (column) adjacency. It does not result in an adjacency for class 5 (row), because the border cells themselves are not evaluated. For this reason, the adjacency matrix must be read as follows: each row represents the adjacency tallies for cells of that class, and the sum of adjacencies across all columns represents the total number of adjacencies for that class. These row totals should equal the number of positively-valued cells (i.e., inside the landscape) of the corresponding class times 4 (i.e., 4 surfaces for each cell). These row totals are used in several of the contagion metrics. Note that the adjacency matrix includes a column for background adjacencies, which represent cell surfaces of the corresponding class adjacent to designated background. If there is no specified background in the input landscape and a landscape border is not present, then the background adjacencies represent the cell surfaces along the landscape boundary–which are treated as background in the absence of a border. If a border is provides and no background is specified, then the background adjacencies with equal zero because every cell surface, including those along the landscape boundary, will be adjacent to a real non-background class. If a batch file is analyzed, the adjacency matrices corresponding to each landscape specified in the batch file are appended to the same file.