[GRASS-user] preferred grid size

Hamish hamish_nospam at yahoo.com
Sun Feb 18 17:23:16 EST 2007

temiz wrote:
> is there any preferred grid size for creating topographic index map ?
> ( elevation map is produced from 1: 25000 scaled topographic map )

[more of a thought experiment than actual educated advice]

PostScript points are 1/72", which equates to a thin line on a printed
page, about as small a feature as is useful in a hardcopy.

For a 1:25,000 scale, that equates to 347.2" or 8.8m.

So a raster resolution of 5m would be ok, but it depends on how big that
makes the data set. A 10000x10000 cell region is probably as big as
you'd want to go, but a 4000x4000 is much easier to work with so perhaps
10m resolution would be a better compromise.

>From the "How to start with GRASS" help page:
"The default raster resolution (GRID RESOLUTION) has to be chosen
according to your needs. Generally, it is advisable to work in steps of
0.25 (0.25, 0.5, 1.75, 2.00, 12.25 etc.)."

I hope I understood and that answers your question,


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