[GRASS-user] Reprojecting and resampling raster map

[Glynn Clements]

stephen sefick wrote:

> When you reproject a raster map to a new location does it
> automatically re-sample it to the regions resolution.

The new map is created using the destination region. The original map
is read at its native resolution, regardless of the source region.

> I have a 10x10
> meter grid in albers equal area projection.  I have reprojected it
> into UTM zone 17 res=50.  This is a base flow index map bfi.  Does
> grass resample the map to 50x50m?

For each 50x50m destination cell, r.proj reverse-projects the cell's
centre coordinate to the source projection, and samples the input map
at the projected coordinate. Exactly how it samples the map depends
upon the method= option (nearest, bilinear, cubic), but the sampling
or interpolation is based upon the raw source map, without any further
resampling.

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