do resolution changes effectively average data ?
mtrimmer at liberty.uc.wlu.edu
Thu Jan 19 12:12:32 EST 1995
> > Hello,
> > In grass, if you have a 10 metre grid resolution raster data layer and
> > you go from 10 metre resolotion to 100 metre resolution using g.region, and then
> > perform an operation on that raster data layer; - does the opertion occur on an
> > averaged value from all original 10 metre grid cells in order to produce the new
> > 100 metre grid raster - or does the operation occur only on the top left 10
> > metre grid cell value within the new 100 metre grid? Or does something else
> > happen?
> > Cheers, Al.
> GRASS resamples based on the value of the center cell. If there is no center
> cell (as in your example), it would take the value of the upper-left cell
> out of the center four, *not* the upper-left cell of the 10 x 10 block.
How about when importing? If I have a DEM with 30m res. and import it into a 100m
res. region, what is the methode GRASS uses to derive the value of the 100m cell?
Washington & Lee University
mtrimmer at wlu.edu
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