R: Landscape Patch Statistics

PatchStat {SDMTools} | R Documentation

## Landscape Patch Statistics

### Description

`PatchStat` calculates the patch statistics for individual patches identified in a matrix of data. The matrix can be a raster of class 'asc' (adehabitat package), 'RasterLayer' (raster package) or 'SpatialGridDataFrame' (sp package).

### Usage

    PatchStat(mat, cellsize = 1, latlon = FALSE)

### Arguments

`mat` | a matrix of data with individual patches identified as with `ConnCompLabel`; The matrix can be a raster of class 'asc' (this & adehabitat package), 'RasterLayer' (raster package) or 'SpatialGridDataFrame' (sp package)
`cellsize` | cell size (in meters) is a single value representing the width/height of cell edges (assuming square cells)
`latlon` | boolean value representing if the data is geographic. If latlon == TRUE, matrix must be of class 'asc', 'RasterLayer' or 'SpatialGridDataFrame'

### Details

The patch statistics are based on statistics calculated by fragstats http://www.umass.edu/landeco/research/fragstats/fragstats.html.

### Value

a data.frame listing

`patchID` | the unique ID for each patch.
`n.cell` | the number of cells for each patch, specified in square meters.
`n.core.cell` | the number of cells in the core area, without the edge area.
`n.edges.perimeter` | the number of outer perimeter cell edges of the patch.
`n.edges.internal` | the number of internal cell edges of the patch.
`area` | the area of each patch comprising a landscape mosaic.
`core.area` | represents the interior area of the patch, greater than the specified depth-of-edge distance from the perimeter.
`perimeter` | the perimeter of the patch, including any internal holes in the patch, specified in meters.
`perim.area.ratio` | the ratio of the patch perimeter (m) to area (m2).
`shape.index` | the shape complexity, sum of each patches perimeter divided by the square root of patch area.
`frac.dim.index` | fractal dimension index reflects shape complexity across a range of spatial scales; approaches 2 times the logarithm of patch perimeter (m) divided by the logarithm of patch area (m2).
`core.area.index` | quantifies core area as a percentage of patch area.

### Author(s)

Jeremy VanDerWal jjvanderwal@gmail.com

### References

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

### See Also

`ClassStat`, `ConnCompLabel`

### Examples

    #define a simple binary matrix
    tmat = { matrix(c( 0,0,0,1,0,0,1,1,0,1,
                       0,0,1,0,1,0,0,0,0,0,
                       0,1,NA,1,0,1,0,0,0,1,
                       1,0,1,1,1,0,1,0,0,1,
                       0,1,0,1,0,1,0,0,0,1,
                       0,0,1,0,1,0,0,1,1,0,
                       1,0,0,1,0,0,1,0,0,1,
                       0,1,0,0,0,1,0,0,0,1,
                       0,0,1,1,1,0,0,0,0,1,
                       1,1,1,0,0,0,0,0,0,1),nr=10,byrow=TRUE) }

    #do the connected component labelling
    ccl.mat = ConnCompLabel(tmat)
    ccl.mat
    image(t(ccl.mat[10:1,]),col=c('grey',rainbow(length(unique(ccl.mat))-1)))

    #calculate the patch statistics
    ps.data = PatchStat(ccl.mat)
    ps.data

[Package SDMTools version 1.1-221.2 Index]