[OSGeo Africa] struggling with gdalwarp

[Zoltan Szecsei]

Howdies Tim,
Will take a look at that.
I'm down to about 30 "bad" images which I have just left out of my 
tiling run (takes 10 hours... :-(  )

Cheers for now,
Zoltan

On 2016-09-01 20:38, Tim Sutton wrote:
> Hi
>
>> On 01 Sep 2016, at 3:55 PM, Zoltan Szecsei <zoltans at geograph.co.za 
>> <mailto:zoltans at geograph.co.za>> wrote:
>>
>> Hi Guys,
>> I've been struggling to get some 3200 orthos mosaicked and tiled.
>> They are very old and have really bad projection definitions, pixel 
>> sizes and metadata funnies.
>> I'm down to the last 261, and have hit a brick wall, likely due to my 
>> not that great "projection definitions" knowledge.
>>
>> I get the following error from gdalwarp:
>>
>>     ERROR 6: Unable to load PROJ.4 library (libproj.so), creation of
>>     OGRCoordinateTransformation failed.
>>
>> I have tried various different gdalwarp parameters - even leaving 
>> gdalwarp to sense in input projection and me only specifying the 
>> output projection.
>> If I leave out both s_srs and t_srs then gdalwarp does work but 
>> obliviously does not reproject to Lo19.
>> I have even tried feeding the output of this redundant gdalwarp into 
>> a gdalwarp with t_srs, but no success.
>>
>> Specifying only t_srs (as above) on many other orthos on Lo17 & Lo21 
>> does work so it is likely that the way this projection is embedded in 
>> this ortho is the problem.
>> I have tried stripping it out with gdal_edit.py but haven't gotten 
>> that right yet.
>>
>> Anyone with pointers or ideas on this?
>
> Have you tried using the corner coordinates and centre to georeference 
> the image. I assume the corner & centre coordinates reported are 
> correct and in LoXX ? There is an example of how to do this in the 
> first reply of this stack exchange post:
>
> http://gis.stackexchange.com/questions/38987/how-can-i-add-all-the-4-corners-as-gcp-in-an-image-that-i-want-to-reproject
>
> Hope that helps!
>
> Regards
>
> Tim
>
> —
>
>
>
>
>
>
>
>
> *Tim Sutton*
>
> *Co-founder:*Kartoza
> *Project chair:*QGIS.org <http://qgis.org>
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