[GRASS-user] DEM with bathymetric contour lines

[Tomáš Brunclík]

PS: Just another wild guess ;)
- Does the input vector bathymetry file contain vector lines? Because 
when I have tried my test, what I downloaded to play with contained 
polygons, not lines and I had to convert it to lines first (something 
like: v.type input=bathymetry output=bathymetry_lines from_type=boundary 
to_type=line). That would also explain your difficulties..
Tomas

Dne 26.5.2015 v 10:38 Tomáš Brunclík napsal(a):
> Hello Irantzu,
> As I said, for anyone to be able to help, please post the exact 
> commands used (all from the beginning, not just the last one which 
> fails) and GRASS version and operating system, just like Markus did in 
> his post. If you are using GUI tools, there is the copy button in the 
> command dialogs, that will allow you to paste the command parameters 
> to e-mail. Also, address the reply back to the conference - more 
> people may have ideas.
> It occurs to me, that if there is no error, and the interpolation 
> throws unchanged input raster on you, that perhaps the input raster 
> contains zero values instead of no-data (null) values or something - 
> then there would be nothing to interpolate... But without seeing the 
> data or the commands used it is just wild guessing..
> Regards,
> Tomas
>
> Dne 25.5.2015 v 13:43 Irantzu Alvarez napsal(a):
>> Hello Tomas,
>> As you said, I think that the problem could be in the volume of data. 
>> My contours are of 300 MB and if I set a region with resolution of 1 
>> m (the one I would like to perform) the output raster has over 3 
>> billion cells. Although I have a high capacity computer, grass doen't 
>> compute the surface.  With a resolution of 10 m my region setting are:
>> g.region -p
>> projection: 1 (UTM)
>> zone:       30
>> datum:      etrs89
>> ellipsoid:  grs80
>> north:      4818930
>> south:      4791480
>> west:       486510
>> east:       601280
>> nsres:      10
>> ewres:      10
>> rows:       2745
>> cols:       11477
>> cells:      31504365
>>
>> I am trying to generalize contours, in order to reduce the contour 
>> file, but I don't know which algorithm is better in that case.
>> After that I will try to use diferrent resolutions to see if that is 
>> the problem.
>>
>> All the best,
>> irantzu
>>
>>
>>
>>
>> 2015-05-25 10:12 GMT+02:00 Tomáš Brunclík <brunclik at atlas.cz 
>> <mailto:brunclik at atlas.cz>>:
>>
>>     Hello,
>>     I tried to process bathymetry lines with negative elevation and
>>     it just worked in GRASS 7.0.1svn r65198 @Linux. Maybe try if it
>>     works with coarser resolution or region subset to test if the
>>     data volume is the problem, or if your version of GRASS really
>>     has problem with negative elevation values. Also try to look if
>>     the input raster contains expected values, if you did not check
>>     that already.
>>     If the problem persists, post your findings with log of the
>>     commands you used, your GRASS version and platform.
>>     If it seems a problem of the GRASS module, and you are using a
>>     recent version of GRASS, it would be better to fill a bug,
>>     instructions at http://grass.osgeo.org/development/bug-tracking/
>>     Regards,
>>     Tomas Brunclik
>>
>>     Dne 18.5.2015 v 16:47 Irantzu Alvarez napsal(a):
>>>
>>>     I am trying to create a DEM from a bathymetric contour lines.
>>>     Contours are in vector format and the elevation value is
>>>     negative (integers). To create the surface I have converted the
>>>     contours in raster (v.to <http://v.to> rast) and then I have
>>>     used r.surf.contour, but It doesn't work (there is no error but
>>>     the resulting output rasteris exactly the same as the previous
>>>     one, without any interpolation).
>>>
>>>     This are my region settings:
>>>
>>>     g.region -p -a raster=contours at iiaa nsres=1 ewres=1
>>>
>>>     projection: 1 (UTM)
>>>
>>>     zone:30
>>>
>>>     datum:etrs89
>>>
>>>     ellipsoid:grs80
>>>
>>>     north:4818927
>>>
>>>     south:4791484
>>>
>>>     west:486512
>>>
>>>     east:601275
>>>
>>>     nsres:1
>>>
>>>     ewres:1
>>>
>>>     rows:27443
>>>
>>>     cols:114763
>>>
>>>     cells:3149441009 <tel:3149441009>
>>>
>>>
>>>
>>>     I need a DEM of very high resolution of a wide area. I am using
>>>     a computer with large capacities for it.
>>>
>>>
>>>     Could someone help me please?
>>>
>>>
>>>     _______________________________________________
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>>>     grass-user at lists.osgeo.org  <mailto:grass-user at lists.osgeo.org>
>>>     http://lists.osgeo.org/mailman/listinfo/grass-user
>>
>>
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>
>
>
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