[gdal-dev] using gdal_viewshed

Tamas Szekeres szekerest at gmail.com
Sun Nov 17 12:24:26 PST 2019


The fix has now been committed to GDAL/master

Tamas

Tamas Szekeres <szekerest at gmail.com> ezt írta (időpont: 2019. nov. 12., K,
22:37):

> I've recently fixed the implementation in my local version causing a
> similar issue (RasterIO error when writing target raster), where the given
> maxdistance setting would produce an empty row at the top or the bottom of
> the result image.
> I'll prepare a fix in gdal in the next few days and let us see if that
> fixes this issue as well.
>
> Best regards,
>
> Tamas
>
>
> Eli Adam <eadam at co.lincoln.or.us> ezt írta (időpont: 2019. nov. 12., K,
> 22:26):
>
>> Hi Ben,
>>
>> On Sun, Nov 10, 2019 at 3:57 AM Ben Avrahami <avrahami.ben at gmail.com>
>> wrote:
>> >
>> > Hello all, I've been trying trying to use the newest gdal_viewshed in
>> gdal-dev release, and I've run into an error I can't quite understand.
>> >
>> > The input I've been using is:
>> >
>> >     gdal_viewshed -md 1000 -ox "691868.511" -oy "3492031.487" <input
>> tiff> <output tiff>
>>
>> It might be helpful to copy and paste your command so if there are
>> typos or otherwise, they can be spotted.
>>
>> A gdalinfo report on your input file could also be helpful.  That
>> would show coordinates of the image and allow looking at things like
>> are those coordinates within the image?  Is it in the coordinate
>> system of the image?  A gdalinfo report details that nicely.
>>
>> >
>> > And I get the response:
>> >
>> >     ERROR 5: C:\temp\files\out.tif, band 1: Access window out of range
>> in RasterIO().  Requested
>> >     (0,-1) of size 67x1 on raster of 67x67.
>> >     ERROR 1: RasterIO error when writing target raster
>>
>> This makes it seem like something isn't lining up correctly.  With the
>> absence of information some random guess include: that the coordinate
>> is not within the image, or perhaps the coordinate is less than -md
>> 1000 units from the edge (although testing that on other data here
>> worked fine), that there are pixel alignment/resolution issues and
>> using coordinates not to three decimal places would work better.
>>
>> I see that gdal_viewshed -md 900 -ox 985710 -oy 658590
>> http://download.osgeo.org/gdal/data/aaigrid/095b_dem_90m.asc
>> output2.tif works
>>
>> and
>>
>> gdal_viewshed -md 800 -ox 985710 -oy 658590
>> http://download.osgeo.org/gdal/data/aaigrid/095b_dem_90m.asc
>> output3.tif fails with the error:
>>
>> 0ERROR 5: output3.tif, band 1: Access window out of range in
>> RasterIO().  Requested
>> (0,-1) of size 19x1 on raster of 19x19.
>> ERROR 1: RasterIO error when writing target raster
>>
>> it seems that -md must be a multiple of the resolution.
>>
>> Best regards, Eli
>>
>> >
>> > I get a similar error if I try to use the GDALViewshedGenerate C-API
>> function. The input us a valid WGS84-UTM tiff file, and the output is a
>> valid path, but the file does not actually exist until I run the command.
>> After I run the command, the output file is created but only filled
>> halfway. Any help at wall would be appreciated.
>> >
>> > regards, Ben
>> > _______________________________________________
>> > gdal-dev mailing list
>> > gdal-dev at lists.osgeo.org
>> > https://lists.osgeo.org/mailman/listinfo/gdal-dev
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>
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