I am trying to merge rasterized polylines which have differing extents, in order to create a single surface indicating the number of times cells overlap.
Due to computational constraints (given the size of my study area), I am unable to use extend and then stack for each raster (total count = 67).
I have come across the merge function in R, and this allows me to merge rasters together into one surface. It doesn't, however, seem to like me inserting a function to compute the sum of overlapping cells.
Maybe I'm missing something obvious, or this is a limitation of the merge function. Any advice on how to generate this output, avoiding extend & stack would be greatly appreciated!
Code:
# read in specific route rasters
raster_list <- list.files('Data/Raw/tracks/rasterized/', full.names = TRUE)
for(i in 1:length(raster_list)){
# get file name
file_name <- raster_list[i]
# read raster in
road_rast_i <- raster(file_name)
if(i == 1){
combined_raster <- road_rast_i
} else {
# merge rasters and calc overlap
combined_raster <- merge(combined_raster, road_rast_i,
fun = function(x, y){sum(x@data@values, y@data@values)})
}
}
Image of current output:
Image of a single route (example):
Image of fix:
