I am currently working on the generation of a hydrologic correct DEM.
As base data I have isolines on a 20k scale and 60000 fix height points for whole Luxembourg (approx. 2500km^2)
I tried first v.surf.rst with the isoline input and it generates in the region of valleys and plateaus artificial artifacts where it isn't able to gather enough data in range of the isolines. It is clearly visible that these represent the segmentation windows of the algorythm.
Because of the processing time (>20h for a small area) I shifted to v.to.points in combination with v.surf.rst and try to include also the fix height points for the interpolation.
Can you tell me some suitable parameters to start with for v.surf.rst in context of using isolines as input. In areas with higher slope I have plenty of representation but I don't have data in flat areas like valleys and plateaus.
Thanks in advance and greetings from Luxembourg,
Christian
Resource Centre for Environmental Technologies,
Public Research Centre Henri Tudor,
Technoport Schlassgoart,
66 rue de Luxembourg,
P.O. BOX 144,
L-4002 Esch-sur-Alzette, Luxembourg
I made some attempts with the attert basin, and I should have a look on
the itial parameters.
The big problem is that you need for different morphological areas also
some different parameters for the splines, so you will always have
problems when generating a DEM for all of Luxembourg.
Best regards
Manuel
(in Wageningen since 4 weeks!)
-----Original Message-----
From: grass-user-bounces@lists.osgeo.org
[mailto:grass-user-bounces@lists.osgeo.org] On Behalf Of
Christian Braun
Sent: donderdag 26 februari 2009 15:53
To: grass-user@lists.osgeo.org
Subject: [GRASS-user] DEM generation with v.surf.rst and isolines
Dear list members,
I am currently working on the generation of a hydrologic correct DEM.
As base data I have isolines on a 20k scale and 60000 fix
height points for whole Luxembourg (approx. 2500km^2) I tried
first v.surf.rst with the isoline input and it generates in
the region of valleys and plateaus artificial artifacts where
it isn't able to gather enough data in range of the isolines.
It is clearly visible that these represent the segmentation
windows of the algorythm.
Because of the processing time (>20h for a small area) I
shifted to v.to.points in combination with v.surf.rst and try
to include also the fix height points for the interpolation.
Can you tell me some suitable parameters to start with for
v.surf.rst in context of using isolines as input. In areas
with higher slope I have plenty of representation but I don't
have data in flat areas like valleys and plateaus.
Thanks in advance and greetings from Luxembourg, Christian
Resource Centre for Environmental Technologies, Public
Research Centre Henri Tudor, Technoport Schlassgoart,
66 rue de Luxembourg,
P.O. BOX 144,
L-4002 Esch-sur-Alzette, Luxembourg
On Thu, February 26, 2009 16:48, Seeger, Manuel wrote:
Hi Christian!
I made some attempts with the attert basin, and I should have a look on
the itial parameters.
The big problem is that you need for different morphological areas also
some different parameters for the splines, so you will always have
problems when generating a DEM for all of Luxembourg.
I am currently working on the generation of a hydrologic correct DEM.
As base data I have isolines on a 20k scale and 60000 fix height points for whole Luxembourg (approx. 2500km^2)
I tried first v.surf.rst with the isoline input and it generates in the region of valleys and plateaus artificial artifacts where it isn’t able to gather enough data in range of the isolines. It is clearly visible that these represent the segmentation windows of the algorythm.
Because of the processing time (>20h for a small area) I shifted to v.to.points in combination with v.surf.rst and try to include also the fix height points for the interpolation.
Can you tell me some suitable parameters to start with for v.surf.rst in context of using isolines as input. In areas with higher slope I have plenty of representation but I don’t have data in flat areas like valleys and plateaus.
Thanks in advance and greetings from Luxembourg,
Christian
Resource Centre for Environmental Technologies,
Public Research Centre Henri Tudor,
Technoport Schlassgoart,
66 rue de Luxembourg,
P.O. BOX 144,
L-4002 Esch-sur-Alzette, Luxembourg
I am currently working on the generation of a hydrologic correct DEM.
As base data I have isolines on a 20k scale and 60000 fix height points for whole Luxembourg (approx. 2500km^2)
I tried first v.surf.rst with the isoline input and it generates in the region of valleys and plateaus artificial artifacts where it isn’t able to gather enough data in range of the isolines. It is clearly visible that these represent the segmentation windows of the algorythm.
Because of the processing time (>20h for a small area) I shifted to v.to.points in combination with v.surf.rst and try to include also the fix height points for the interpolation.
Can you tell me some suitable parameters to start with for v.surf.rst in context of using isolines as input. In areas with higher slope I have plenty of representation but I don’t have data in flat areas like valleys and plateaus.
Thanks in advance and greetings from Luxembourg,
Christian
Resource Centre for Environmental Technologies,
Public Research Centre Henri Tudor,
Technoport Schlassgoart,
66 rue de Luxembourg,
P.O. BOX 144,
L-4002 Esch-sur-Alzette, Luxembourg