[GRASS-user] DEM with bathymetric contour lines
Tomáš Brunclík
brunclik at atlas.cz
Tue Jun 2 01:18:04 PDT 2015
Hello all,
after about 10 hours of processing (the computer got to sleep state over
night) still progress 0%. Is it normal on such region size and core i5 PC?
T. Brunclik
Dne 1.6.2015 v 11:44 Tomáš Brunclík napsal(a):
> Hi Irantzu,
> I am just trying again with this dataset:
> https://dl.dropboxusercontent.com/u/24062833/ES2003_1m_mb_contour.zip
> It is cosiderably smaller than yours, with 1m resolution the region is
> 5676x4142 pixels, but running r.surf.contour for 15 minutes and still
> 0% done. Hope it is able to finish before I have to leave, I have
> common office PC. In any case I will let you know what was the result,
> you can try with the same data for comparison.
> Looking at the data, which are of some inland water body, I see the
> most of the region area is covered by land, which is not covered by
> contours (there are contours for elevation <= 0 only). Would see how
> the command copes with that, this could possibly be source of your
> problems, should your data also contain large areas not covered by the
> contours. It such case a mask may help.
> Regards,
> Tomas
>
> For the record, the commands I used:
>
> #First created new location using the data as source of its projection
> settings and imported the file (from startup GUI), then:
>
> g.region vector=ES2003_1m_mb_contour at PERMANENT
>
> g.region res=1
>
> g.region -p
> projection: 1 (UTM)
> zone: 10
> datum: wgs84
> ellipsoid: wgs84
> north: 4079792.873656
> south: 4074116.9543482
> west: 608344.55566446
> east: 612486.8266235
> nsres: 0.99998578
> ewres: 1.00006542
> rows: 5676
> cols: 4142
> cells: 23509992
>
> v.to.rast input=ES2003_1m_mb_contour at PERMANENT output=contours_rast
> attribute_column=CONTOUR
>
> r.surf.contour input=contours_rast output=dmt_rast
>
>
>
> Dne 31.5.2015 v 20:21 Irantzu Alvarez napsal(a):
>> Hi Markus and Tomas,
>> Thank you very much for all your support.
>>
>> I am using Grass 7.0 in linux and I am working in a high capacity
>> computer.
>>
>> My bathymetry input file contains vector lines, and all of them have
>> an elevation value, from -2 to -116, with an interval of 1 m. The
>> file have 300 MB.
>>
>> After executing the v.to.rast command, I get a raster, and it seems
>> that is correct (pixels have the value of the elevation).
>> I am trying to change te resolution in order to get the
>> interpolation. If I choose a resolution of 1 meter, the output file
>> is exactly the same as the previous one, but if I change it (for
>> example a resolution of 100 m), it works, but with a very bis pixexl
>> size. The question is that I need a high resolution DEM.
>> This are the commands I have used:
>>
>> v.to.rast input=iso1 at ras type=line output=ras_ir use=attr
>> attribute_column=CONTOUR
>> r.surf.contour --overwrite input=ras_ir at ras output=mdt_ras
>>
>> Regards,
>>
>> Irantzu
>>
>> 2015-05-26 10:50 GMT+02:00 Tomáš Brunclík <brunclik at atlas.cz
>> <mailto:brunclik at atlas.cz>>:
>>
>> 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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