[GRASS-user] DEM resolution from r.surf.contour

[Hanlie Pretorius]

GRASS 6.4.1 on Windows XP.

g.region output for 5m resolution:

g.region -p vect=contours_20m at PERMANENT nsres=5 ewres=5
projection: 99 (Transverse Mercator)
zone:       0
datum:      ** unknown (default: WGS84) **
ellipsoid:  wgs84
north:      -3121229.69982072
south:      -3156672.30728643
west:       -67483.27873573
east:       -32474.90929218
nsres:      4.9996625
ewres:      4.99976713
rows:       7089
cols:       7002
cells:      49637178

g.region output for 20m resolution:
g.region -p vect=contours_20m at PERMANENT nsres=20 ewres=20
projection: 99 (Transverse Mercator)
zone:       0
datum:      ** unknown (default: WGS84) **
ellipsoid:  wgs84
north:      -3121229.69982072
south:      -3156672.30728643
west:       -67483.27873573
east:       -32474.90929218
nsres:      20.00147148
ewres:      20.00478254
rows:       1772
cols:       1750
cells:      3101000

Thanks
Hanlie

2011/5/6, Markus Neteler <neteler at osgeo.org>:
> On Wed, May 4, 2011 at 10:48 AM, Hanlie Pretorius
> <hanlie.pretorius at gmail.com> wrote:
>> Hi,
>>
>> I'd like to ask a question related to another question I was asking
>> recently about converting contour vectors to rasters and creating a
>> DEM from the raster contours using r.surf.contour.
>>
>> My supplied vector contour layer has 20m intervals between contour
>> lines. When I convert this to raster, the smallest region resolution I
>> can use is 5m, otherwise v.to.rast runs out of memory.
>
> Please post
> - GRASS version/OS
> - g.region -p output
> to better understand the problem.
>
> Markus
>
>> When I use r.surf.contour to create the DEM from the raster, which
>> region resolution makes sense then? I set it to 20m because of the
>> contour interval, but I'm starting to think that's not the best option
>> because the interpolation between two contour lines should be as fine
>> as possible.
>>
>> Any thoughts?
>>
>> Thanks
>> Hanlie
>