Hi Christophe, Have a look at the following:
https://lists.osgeo.org/pipermail/gdal-dev/2016-January/043358.html https://gis.stackexchange.com/questions/37790/how-to- reproject-raster-from-0-360-to-180-180-with-cutting-180-meridian I'd suggest building a couple of VRT files to treat your data as -180 to +180, then project each independently to EPSG:3857. I'm sure there used to be an example in the GDAL docs, but I can't find it - maybe I'm imagining it :) As I’m new on this mail list do I have to “Reply All”? or just reply to you? Reply all is good — that way everyone can read it. Cheers, Rob. On 7 March 2018 at 13:05, LAVOYE Christophe <christophe.lav...@akka.eu> wrote: > Hi Robert, > > > > You could find my sample in attached files. > > > > This is the gdal informations: > > > > Driver: GTiff/GeoTIFF > > Files: D:\TEMP\TempProjectionsV2\BASE\baseAnteMeridien.tiff > > Size is 900, 803 > > Coordinate System is: > > GEOGCS["WGS 84", > > DATUM["WGS_1984", > > SPHEROID["WGS 84",6378137,298.257223563, > > AUTHORITY["EPSG","7030"]], > > AUTHORITY["EPSG","6326"]], > > PRIMEM["Greenwich",0], > > UNIT["degree",0.0174532925199433], > > AUTHORITY["EPSG","4326"]] > > GeoTransform = > > 179.9362167765823, 0.001541256882521351, 1.892378333877928e-005 > > 66.12419696670919, 9.991578318404334e-006, -0.0006775726479453831 > > Metadata: > > AREA_OR_POINT=Area > > TIFFTAG_XRESOLUTION=96 > > TIFFTAG_YRESOLUTION=96 > > Image Structure Metadata: > > COMPRESSION=JPEG > > INTERLEAVE=PIXEL > > Corner Coordinates: > > Upper Left ( 179.9362168, 66.1241970) (179d56'10.38"E, 66d 7'27.11"N) > > Lower Left ( 179.9514126, 65.5801061) (179d57' 5.09"E, 65d34'48.38"N) > > Upper Right ( 181.323, 66.133) (181d19'24.05"E, 66d 7'59.48"N) > > Lower Right ( 181.339, 65.589) (181d20'18.76"E, 65d35'20.75"N) > > Center ( 180.6373803, 65.8566478) (180d38'14.57"E, 65d51'23.93"N) > > Band 1 Block=900x803 Type=Byte, ColorInterp=Red > > Band 2 Block=900x803 Type=Byte, ColorInterp=Green > > Band 3 Block=900x803 Type=Byte, ColorInterp=Blue > > > > So my question concerns data which past +180° a > > > > I made old tests where I first cut my image and then make two warp > operations and I remember it was working. I didn’t try to re-associate then. > > I have to test. > > > > As I’m not an expert I want to know the best approach to enable > reprojection on those kind of data with coordinate over +180°. > > > > As I’m new on this mail list do I have to “Reply All”? or just reply to > you? > > > > Best regards, > > > > > > [image: cid:image003.png@01D1FD34.3B7C8CC0] > > *Christophe LAVOYE - **Analyste* > * AKKA Technologies *Informatique & Systèmes > 7 boulevard Henri Ziegler – 31700 BLAGNAC > <https://maps.google.com/?q=7+boulevard+Henri+Ziegler+%E2%80%93+31700+BLAGNAC&entry=gmail&source=g> > Tél : +33 (0)5 36 25 15 40 <+33%205%2036%2025%2015%2040> > Email : christophe.lav...@akka.eu > > > > > > *De :* Robert Coup [mailto:robert.c...@koordinates.com] > *Envoyé :* mercredi 7 mars 2018 12:33 > *À :* LAVOYE Christophe > *Cc :* gdal-dev@lists.osgeo.org > *Objet :* Re: [gdal-dev] [help][gdalwarp]Use of gdalwarp with data > overlapping antimeridian > > > > Hi Christophe, > > > > What do you *expect or want* to happen with your images? > > > > Are your 4326 image coordinates in -180° to +180° range (ie. the right > longitude is < the left); or do they go past +180°? > > > > 3857 is a projected coordinate system, so doesn't have a builtin concept > of wrapping. Some clients implement. > > Do you want x values >20037508.34? But they'll only display on the "right" > side of the world then (if at all). > > > > The simplest approach is likely to be to do two warp operations, for the > left and right parts, ending up with two images — one with > left=-20037508.34 and one with right=+20037508.34 > > > > Rob :) > > > > > > On 1 March 2018 at 15:23, LAVOYE Christophe <christophe.lav...@akka.eu> > wrote: > > Hello, > > > > I’m using GDAL library in a C# project. > > > > To reproject some geotiff files i’m calling gdalwarp tool as external > process with this command: > > > > gdalwarp.exe -s_srs EPSG:4326 -t_srs EPSG:3857 -dstalpha input.tiff > output.tiff > > > > > > All works fine except for data overlapping antimeridian such as the > associated tiff file. > > > > I don’t find how fix my problem or if I’m using the correct tool for those > kind of data. > > > > > > Best regards, > > > > > > [image: cid:image003.png@01D1FD34.3B7C8CC0] > > *Christophe LAVOYE - **Analyste* > * AKKA Technologies *Informatique & Systèmes > 7 boulevard Henri Ziegler – 31700 BLAGNAC > <https://maps.google.com/?q=7+boulevard+Henri+Ziegler+%E2%80%93+31700+BLAGNAC&entry=gmail&source=g> > Tél : +33 (0)5 36 25 15 40 <+33%205%2036%2025%2015%2040> > Email : christophe.lav...@akka.eu > > > > > > > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/gdal-dev > > > > > > -- > > Chief Technology Officer Koordinates > > +44 759 987 3480 <+44%20759%209873480> / koordinates.com / @koordinates > <https://twitter.com/koordinates> > -- Chief Technology Officer Koordinates +44 759 987 3480 <+44%20759%209873480> / koordinates.com / @koordinates <https://twitter.com/koordinates>
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