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Raster to polygons conversion. Cells with NA are not converted. A function can be used to select a subset of the raster cells (by their values).
rasterToPolygons(x, fun=NULL, n=4, na.rm=TRUE, digits=12, dissolve=FALSE)
Raster* object
function to select a subset of raster values (only allowed if x has a single layer)
x
integer. The number of nodes for each polygon. Only 4, 8, and 16 are allowed
If TRUE, cells with NA values in all layers are ignored
TRUE
NA
number of digits to round the coordinates to
logical. If TRUE, polygons with the same attribute value will be dissolved into multi-polygon regions. This option requires the rgeos package
SpatialPolygonsDataFrame
fun should be a simple function returning a logical value.
fun
E.g.: fun=function(x){x==1} or fun=function(x){x>3 & x<6}
fun=function(x){x==1}
fun=function(x){x>3 & x<6}
# NOT RUN { r <- raster(nrow=18, ncol=36) r[] <- runif(ncell(r)) * 10 r[r>8] <- NA pol <- rasterToPolygons(r, fun=function(x){x>6}) #plot(r > 6) #plot(pol, add=TRUE, col='red') # }
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