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

Sat Dec 13 16:02:06 PST 2014

I'm installing qgis right now to try, hopefully it's not too
complicated. 

I think haedarpunkar is just mountain peaks, not full details providing
the contour like the polygons are - when I rendered it out with
gdal_rasterize the points were very sparse. I know nothing about the
internal details of these files, though. My only prior experience with
GIS was years ago working with SRTM data, and my copy of the data came
pre-rasterized.

There's so many data files here of different formats on the site that I
provided you (including in the dataset you already downloaded), surely
there's something that contains something I can work with. For example,
there's 211 megs of data in IS50V_HAEDARGOGN.gdb, which I would assume
is GDB format, which gdal says it supports, but I can't figure out how
use it because there's no single ".gdb" file, it's a bunch of tables.
And there's also the whole different dataset HAEDARLIKAN_LMI which
contains an img and a 1 gig ige file, but it looks like they're not
supported by gdal.

I'm getting so desperate here that I've started trying to color in and
shade the curves from haedarlinur by hand  :(  As you might expect, it's
taking forever and not going very well.

 - kv, Karen

On lau, 2014-12-13 at 23:33 +0000, Ari Jolma wrote:
> Karen,
> 
> What is the field with the elevations? I tried with HAEDDYPIME:
> 
>   gdal_grid -of GTiff -l is50v_haedarpunktar_24122013 -outsize 1000 1000 
> -zfield HAEDDYPIME is50v_haedarpunktar_24122013.shp x.tiff
> Grid data type is "Float64"
> Grid size = (1000 1000).
> Corner coordinates = (248491.242441 674738.882768)-(757263.099390 
> 311759.059646).
> Grid cell size = (508.263593 362.617206).
> Source point count = 10298.
> Algorithm name: "invdist".
> Options are 
> "power=2.000000:smoothing=0.000000:radius1=0.000000:radius2=0.000000:angle=0.000000:max_points=0:min_points=0:nodata=0.000000"
> 
> 0...10...20...30...40...50...60...70...80...90...100 - done.
> 
> The result is not very good.
> 
> I suggest you install for example QGIS for looking at the result.
> 
> Best,
> 
> Ari
> 
> 13.12.2014, 19:32, Karen Pease kirjoitti:
> > The problem exists when I output straight to a PNM as well, not just
> > with geotiff.
> >
> > Can you give me an example gdal_grid command which actually works to
> > create a heightmap image that your average program can read? Because I'm
> > getting nowhere. :( For example, as a test:
> >
> > gdal_grid -ot Byte -of PNM -l is50v_haedarpunktar_24122013 -outsize 800
> > 500 is50v_haedarpunktar_24122013.shp y.pnm
> >
> > y.pnm comes up as black. od shows that y.pnm is truly blank:
> >
> > 0000000 032520 034012 030060 032440 030060 031012 032465 000012
> > 0000020 000000 000000 000000 000000 000000 000000 000000 000000
> > *
> > 1415200 000000 000000 000000 000000 000000 000000 000000 000000
> > 1415217
> >
> > 	- kv, Karen
> >
> >
> >
> > On lau, 2014-12-13 at 19:09 +0000, Ari Jolma wrote:
> >> 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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