[GRASS-user] UTM concepts

[Glynn Clements]

Matthew Perry wrote:

> First, for raster data. Lets say you have a raster dataset where each
> pixel represents a physical, measurable count; for example each pixel
> contains the number of humans who live in the geographic space
> represented by the pixel. If you reproject that data, the actual space
> covered by a pixel changes! Any reprojection routine will simply
> recalculate the value of each pixel based on the chosen resampling
> algorithm. If you take a population raster and reproject it, there is
> a very little chance that the sum of the overall raster cells will be
> maintained... By reprojecting you have altered your dataset and
> changed the overall population!

On a (slightly) related note, would it be worth extending
r.resamp.stats to allow method=sum?

-- 
Glynn Clements <glynn at gclements.plus.com>