[gdal-dev] Can't get gdal_rasterize to work... with anything.

[Ari Jolma]

13.12.2014, 18:07, Karen Pease kirjoitti:
> Okay, so, I think this may be getting me a bit closer to a solution.
>
> The output image of your command still wasn't viewable to me, either in
> gimp or gwenview. However, when I used ImageMagick to convert it to a
> PNG or other format, for the first time I saw some detail, so I guess
> it's a tif format that the former two can't read. I tried this approach
> on the actual dataset I want to use - IS50V_HAEDARGOGN_24122013_ISN2004.
> And indeed, the two stage process worked - to get height lines. But what
> I actually want is a 3d height map image, where dark colors are low and
> bright colors are high and so forth. So I switched from -burn 1 to the
> -3d flag. Now it started outputting 64 bit float files, however; convert
> couldn't handle them, nor tifftopnm. So I went back to specifying -ot
> Byte or -ot UInt16 so I can use convert. However, the images just come
> out all black. This is the same result I get if output directly to pnm
> with -of PNM.
Karen,

GeoTIFFs are usually only for GIS programs, not for general image viewers.

I downloaded the elevation data (~500 MB) and to me it looks like it is 
elevation points and lines. To make a DEM (raster where cell values are 
elevations) you would need to use a tool like gdal_grid with the point file.

Best,

Ari

>
> 	- kv, Karen
>
>
>
> On lau, 2014-12-13 at 09:18 +0000, Ari Jolma wrote:
>> Karen,
>>
>> For example this command on my computer
>>
>> gdal_rasterize -burn 1 -l is50v_mannvirki_flakar_24122013 -of GTiff -ts
>> 1000 1000 is50v_mannvirki_flakar_24122013.shp x.tiff
>>
>> produces a 1000 x 1000 geotiff which is mostly zeros except ones where
>> the polygons are.
>>
>> Can you tell us what command did you use?
>>
>> Ari
>>
>> ps: the website was a bit difficult to use for non-icelanders.
>>
>> 13.12.2014, 06:18, Karen Pease kirjoitti:
>>> Hi all,
>>>
>>> I'm running Fedora 21 with a fresh built gdal-1.9.2. Try as I might, I
>>> can't get gdal_rasterize to output anything other than purely
>>> transparent images, purely white images, or purely black images.
>>>
>>> I want to use it on this dataset - "Elevation data. GDB og SHP.
>>> ISN2004":
>>>
>>> http://atlas.lmi.is/LmiData/index.php?id=1079838344912
>>>
>>> I've spent maybe 8 hours on this, including trying all sorts of
>>> different commandlines. After finding that I couldn't get that to work,
>>> I found some sample tutorials that includes a shp file and some command
>>> lines to use it with gdal_rasterize:
>>>
>>> http://disc.sci.gsfc.nasa.gov/dataholdings/?q=recipes/How-to-Obtain-a-Shapefile-based-Data-Subset-with-GrADS
>>> http://www.openforis.org/OFwiki/index.php/Special:WhatLinksHere/Example_data_set
>>>
>>> None of these work for me either (using it exactly as they say to), so I
>>> don't think it's my shp files that's the problem; I think it's
>>> gdal_rasterize or something it depends on. I know the problem isn't an
>>> image viewer problem either - I've tried multiple viewers, and I've
>>> tried saving the files to PNM to allow for manual inspection - they all
>>> contain only the same data value repeated over and over, no variation,
>>> just pure one color.
>>>
>>> What should I do? I really need to make a heightmap out of this
>>> landscape data for inclusion into a 3d model...
>>>
>>>    - kv, Karen
>>>
>>>
>>>
>>>
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