zonal_stat | R Documentation |
'Zonal' operator of map algebra. Applied to raster images.
zonal_stat(x, by, FUN, table = FALSE) ## S3 method for class 'ursaRaster' aggregate(x, by, FUN, table = FALSE, ...)
x |
|
by |
|
FUN |
a function to compute the summary statistics which can be applied to all data subsets. |
table |
Logical. If |
... |
Other arguments which passed to function |
zonal_stat
is a wrapper of aggregate(x,by,FUN,table=FALSE,na.rm=TRUE)
You can use multichannel image (argument x
) for analysis.
You can use multichannel raster image for group elements (argument by
)
If table=FALSE
then ursaRaster
object of summarized statistics.
If table=TRUE
then data.frame
.
Nikita Platonov platonov@sevin.ru
session_grid(NULL) session_grid(regrid(mul=1/2)) a <- pixelsize() val <- c(normal=a,half=a/2) gr <- c(group=colorize(a,nbreak=1))#+0 print(as.table(gr)) ##~ display(gr) ra <- round(aggregate(val,gr,mean),4) print(ra) print(as.table(ra[1])) print(as.table(ra[2])) da <- aggregate(val,gr,table=TRUE,mean) n <- aggregate(a,gr,table=TRUE,length)[,2,drop=FALSE] da <- cbind(da,n=unname(n)) gr2 <- c(group2=colorize(a,nbreak=6))#+0 mgr <- list(gr,gr2) da2 <- aggregate(val[1],mgr,table=TRUE,mean) print(da2) da3 <- aggregate(val,mgr,table=TRUE,mean) print(da3) ra3 <- aggregate(val,mgr,table=FALSE,mean) ## not implemented for rasters print(ra3)
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.