[gdal-dev] Reprojecting image with lat/lon bands - best practice?

[Michael Sumner]

Nice one, thanks! (I had a fomenting PR to implement on the fly geolocation
array config, so I'll use your hallucination for the design phase).

🤟

On Sat, 19 Oct 2024, 14:44 Even Rouault, <even.rouault at spatialys.com> wrote:

>
> Le 18/10/2024 à 23:32, Michael Sumner a écrit :
>
> I didn't know you could do that with -to!! That's awesome
>
> 🤟
>
> Hum, sorry for giving a wrong track, it seems the newly LLM module
> implemented in my brain has hallucinated...
>
> So you have rather to create a geoloc.vrt file with
>
> gdal_translate input.tif geoloc.vrt -b 2 -b 1
>
> and then;
>
> gdal_translate input.tif imagery.vrt -b 3
>
> gdalwarp imagery.vrt imagery_warped.tif -geoloc -to
> GEOLOC_ARRAY=geoloc.vrt -a_srs EPSG:4326  -overwrite
>
>
> On Sat, 19 Oct 2024, 05:01 Even Rouault via gdal-dev, <
> gdal-dev at lists.osgeo.org> wrote:
>
>> Conrad,
>>
>> Try something like:
>>
>> gdal_translate input.tif imagery.vrt -b 3
>>
>> gdalwarp imagery.vrt imagery_warped.tif -geoloc -to X_DATASET=input.tif
>> -to X_BAND=2 -to Y_DATASET=input.tif -to Y_BAND=1 -to PIXEL_OFFSET=0 -to
>> PIXEL_STEP=1 -to LINE_OFFSET=0 -to LINE_STEP=1 -to SRS=EPSG:4326 -a_srs
>> EPSG:4326  -overwrite
>>
>> Obviously I have most certainly got something wrong in the above, but
>> hopefully with a tiny tweaking that should put you on the right track.
>>
>> Reference: https://gdal.org/en/latest/development/rfc/rfc4_geolocate.html
>>
>> Even
>> Le 18/10/2024 à 12:37, Javier Jimenez Shaw via gdal-dev a écrit :
>>
>> Is it an actual grid? in the meaning of having constant step size in X
>> and Y.
>> In that case the geolocation is just the corner and the x and y sizes.
>> You can convert to a georeference raster, and warp it.
>> If it is not the case, you have something more like a 2D pointcloud, or a
>> bunch of poins in a strange vector format.
>>
>> On Fri, 18 Oct 2024 at 12:20, Conrad Bielski via gdal-dev <
>> gdal-dev at lists.osgeo.org> wrote:
>>
>>> Hello GDAL-experts,
>>>
>>> normally when I use GDAL for reprojecting imagery, the projection
>>> information that I use is the source spatial reference (SRS) associated
>>> with the imagery. However, now I have imagery which is lat/lon geographic
>>> and I have two separate bands which also carry the pixel geographic
>>> information. So the following raster inputs all the same size:
>>> 1. Band 1 = latitude
>>> 2. Band 2 = longitude
>>> 3. Band 3 = imagery
>>>
>>> The question I have is how best to integrate this information into a
>>> reprojection workflow?
>>>
>>> I presume that gdalwarp is the best option here, but how can I take
>>> advantage of the individual pixel location information (rather than just
>>> the extents for example)? I know that I can mosaic into an existing file
>>> that I have already created in the target projection. Is this the best way
>>> to apply gdalwarp in this context?
>>>
>>> I'm just wondering what is the best way to integrate the lat/lon pixel
>>> information into my warping using gdalwarp.
>>>
>>> Thanks in advance for your help,
>>> Conrad
>>> _______________________________________________
>>> gdal-dev mailing list
>>> gdal-dev at lists.osgeo.org
>>> https://lists.osgeo.org/mailman/listinfo/gdal-dev
>>>
>>
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>>
>> -- http://www.spatialys.com
>> My software is free, but my time generally not.
>> Butcher of all kinds of standards, open or closed formats. At the end, this is just about bytes.
>>
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>>
> -- http://www.spatialys.com
> My software is free, but my time generally not.
> Butcher of all kinds of standards, open or closed formats. At the end, this is just about bytes.
>
>
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