arcgis-10.0arcgis-desktopdatarasterraster-calculator
To calculate any formula (conditional statements/relational operation etc) in the raster calculator in ArcGIS using two different sources of raster images, I'd like to know input rasters must be the same size (row, col num) or not.
Generally, cell sizes of input rasters are the same but col and row numbers are slightly different.
Can the raster calculator operation manage their sizes automatically?
When you run geoprocessing operations in ArcMap (e.g. tools from the ArcToolbox pane) they conform to two sets of parameters. First are the parameters in the window itself, e.g. input file, output file path, etc. Second are the parameters in the Environment Settings window (see below).
These Environment Settings let you fine-tune your geoprocessing operations in myriad ways. In your case, you want the interpolation image to have the same extent, same pixel size, and same pixel registration (i.e. the corners of the pixels are in the exact same spot). To do this, choose your NDVI data files for the "Extent" and "Snap Raster" parameters under the "Processing Extent" heading (see below). By doing this, the output raster from the interpolation will have the same processing extent and pixel registration as the NDVI data.
If you want Environment settings to persist across multiple geoprocessing operations, you can set environments for the entire Map Document by opening the Environments window under the "Geoprocessing" menu in ArcMap (see below).
The raster package has a function to do this for you in one line. Use layerize():
library(raster)
# make an example raster
r <- raster(nrow=100, ncol=100)
r[] <- round(runif(ncell(r),1,4),0)
# create presence/absence rasters, stored in a RasterBrick.
r_dummy <- layerize(r)
plot(r_dummy[[1]])
Best Answer
It will depend on the tool, but typically the intersection or minimum of inputs will be the default processed in them. More specific documentation on extent (what you are presumably meaning when you indicate sizes or row/col of rasters) with respect to environments settings and how you can change this can be read here: