[GRASS-stats] How to make histogram in R from raster of grass

[pvanbosgeo]

If you import a GRASS raster, you'll get a SpatialGridDataFrame object.
Suppose your spatialgriddataframe is called 'myrast'. You can find out the
structure of that object using str(myrast). You'll find that the raster
values are in myrast at data. You can extract the data as data frame 

myrast.data <- myrast at data

Now you can create histograms as you would normally do. 

Especially when you are dealing with very large raster layers, a good
alternative is to use the 'raster' package to import the raster layer. You
can then use the hist function to create a histogram of the values of a
RasterLayer directly. For large datasets the hist function in the raster
package automatically uses a sample.





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