[Gdal-dev] ENVISAT data comes out left-right fliped
jluis at ualg.pt
Tue Feb 7 11:38:18 EST 2006
Frank Warmerdam wrote:
> On 2/3/06, Julien Demaria <dem at acri-st.fr> wrote:
>>This isn't a bug.
>>MERIS Envisat files are geolocated using a GCPs list (in fact one GCP
>>every 16 pixels). In the swath the file is left-right fliped, but it's
>>the specifications. If you want apply the GCPs projection and then flip
>>LR the file, you should use the gdalwarp GDAL utility:
>>gdalwarp MER_RR__1_Mediterranean.n1 MER_RR__1_Mediterranean.tif
>>(tested on Linux with FWTools-linux-1.0.0a7).
>>I've successfully viewed your file using FWTools OpenEV (FWTools1.0.0a8
>>on Windows). With it you can directly display (unflipped) your .n1 file
>>since OpenEV reproject on-the-fly the file using GCPs :)
> Julien is dead-on in his analysis. The images are
> stored in a manner related to how they are collected,
> but the geolocation info (GCPs) should allow you to
> warp the image to north up if that is what you need.
Frank and Julien,
I had some troubles with my mail and this subject slipped without acknowledgment.
Now that I now it I added a test (if ESAT) on my code to read it flipped.
I have not (yet?) implemented a warp facilitie to this importing code.
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