[GRASS5] [bug #2357] (grass) Working with rasters in diverse resolutions

Morten Hulden morten at untamo.net
Mon Mar 15 16:17:25 EST 2004

On Mon, 15 Mar 2004, Request Tracker wrote:

> this bug's URL: http://intevation.de/rt/webrt?serial_num=2357
> -------------------------------------------------------------------------
> Subject: Working with rasters in diverse resolutions
> Platform: other
> grass obtained from: Trento Italy site
> grass binary for platform: Downloaded precompiled Binaries
> GRASS Version: 5.0.3
> Hello,
> I am working with multiple raster data sets in diverse resolutions, which presents a problem.  For example, I cannot easily overlay a 1 meter-resolution USGS quad on a 30 meter-resolution DEM.  To get all the data out of the quad I have to oversample the DEM 900 times by setting the project resolution to 1m.
> It seems to me that implementing support for multiple resolutions at once would be a gargantuan pain for the poor programmers, but this is (imho) a serious limitation of the program.  Is there a workaround that doesn't involve choking my RAM with oversampled data?  Is there perhaps a workaround in NVIZ?
> Thanks,
> Gilead Wurman
> ASU Active Tectonics

There is no need to oversample. Within a location you can create named 
regions which differ from the default region in resolution and/or 
geographic coverage.

If the resolution of your default region is 30m and you want to import a
1m map, then create a new 1m region and switch to that before importing.  
Or the other way around if your default is 1m.

The display driver will understand how to overlay maps with different 

Morten Hulden

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