ZonalStat {SDMTools} | R Documentation |
ZonalStat
calculates the statistics of data for
specified zones of two matrices of data. The matrix can be
a raster of class 'asc' (adehabitat package), 'RasterLayer'
(raster package) or 'SpatialGridDataFrame' (sp package).
ZonalStat(mat, zones, FUN = "all")
mat |
a matrix of data to be summarized; The matrix can be a raster of class 'asc' (adehabitat package), 'RasterLayer' (raster package) or 'SpatialGridDataFrame' (sp package) |
zones |
a matrix of data with individual patches
identified as with |
FUN |
a single or vector of functions to be applied to each 'zone'; the default of 'all' will calculate min, 1st quarter, median, 3rd quarter, max, mean, standard deviation and n |
The code summarizes the data for defined zones. Nearly any
function can be used for summarizing the data.
The
FUN defined with 'all' as one of or the only function will
append the functions of min, 1st quarter, median, 3rd
quarter, max, mean, standard deviation and n to what is
being calculated.
a data.frame listing
zone |
the unique ID for each zone. |
functions... |
a column for each of the functions identified |
The data.frame will have an atribute defining the number of NA values that were excluded from the analysis.
Jeremy VanDerWal jjvanderwal@gmail.com
#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 #this is the zone matrix to be used #create a random data matrix data.mat = matrix(runif(100),nr=10,nc=10) data.mat #calculate the zonal statistics zs.data = ZonalStat(data.mat,ccl.mat,FUN='all') zs.data #just calculate the sum zs.data = ZonalStat(data.mat,ccl.mat,FUN='sum') zs.data #calculate sum & n & 'all' and show when a function is not defined zs.data = ZonalStat(data.mat,ccl.mat, FUN=c('sum','length','not.a.function','all')) zs.data attr(zs.data,'excluded NAs') #show how many NAs were omitted from analysis