[gdal-dev] help with gdalwarp
Hi all, Sorry for a newbie question. I've been reading this list and searching elsewhere for a few days now to try to figure this out, but I'm still missing something. I need to reproject a map from Plate Caree projection to Lambert Azimuthal Equal Area projection centered on 0N,15E with gdalwarp. I'm using a Natural Earth II map from http://www.shadedrelief.com/natural2/. The map http://www.nacis.org/data/NE2/NE2_land_only.jpg is 16200x8100 pixels, plate caree, WGS84. It also has a world file http://www.shadedrelief.com/natural2/images/world_16000.zip with following information. 0.02 0.00 0.00 -0.02 -180.00 90.00 I run gdalwarp with following parameters: gdalwarp -s_srs +proj=eqc +lat_ts=0 +lon_0=0 +datum=WGS84 -t_srs +proj=laea +lat_0=0 +lon_0=15 +x_0=0 +y_0=0 +datum=WGS84 -co INTERLEAVE=PIXEL -co TFW=YES -of GTiff c:\dgwarp\source_images\NE2_land_only.jpg c:\dgwarp\NE2_land_only_laea.tif But the resulting image looks basically the same as the input, definitely not like LAEA should look. gdalinfo on the output image shows strange corner coordinates: Driver: GTiff/GeoTIFF Files: NE2_land_only_laea.tif Size is 16166, 8168 Coordinate System is: PROJCS[unnamed, GEOGCS[WGS 84, DATUM[WGS_1984, SPHEROID[WGS 84,6378137,298.2572235630016, AUTHORITY[EPSG,7030]], AUTHORITY[EPSG,6326]], PRIMEM[Greenwich,0], UNIT[degree,0.0174532925199433], AUTHORITY[EPSG,4326]], PROJECTION[Lambert_Azimuthal_Equal_Area], PARAMETER[latitude_of_center,0], PARAMETER[longitude_of_center,15], PARAMETER[false_easting,0], PARAMETER[false_northing,0], UNIT[metre,1, AUTHORITY[EPSG,9001]]] Origin = (-1665206.34306095800,90.180212867784576) Pixel Size = (0.022078666990796,-0.022078666990796) Metadata: AREA_OR_POINT=Area Image Structure Metadata: INTERLEAVE=PIXEL Corner Coordinates: Upper Left (-1665206.343, 90.180) ( 0d 0'5.82W, 0d 0'2.91N) Lower Left (-1665206.343, -90.158) ( 0d 0'5.82W, 0d 0'2.91S) Upper Right (-1664849.419, 90.180) ( 0d 0'5.82E, 0d 0'2.91N) Lower Right (-1664849.419, -90.158) ( 0d 0'5.82E, 0d 0'2.91S) Center (-1665027.881, 0.011) ( 0d 0'0.00W, 0d 0'0.00N) Band 1 Block=16166x1 Type=Byte, ColorInterp=Red Band 2 Block=16166x1 Type=Byte, ColorInterp=Green Band 3 Block=16166x1 Type=Byte, ColorInterp=Blue What am I missing? ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] help with gdalwarp
Alex Bernstein wrote: Hi all, Sorry for a newbie question. I've been reading this list and searching elsewhere for a few days now to try to figure this out, but I'm still missing something. I need to reproject a map from Plate Caree projection to Lambert Azimuthal Equal Area projection centered on 0N,15E with gdalwarp. I'm using a Natural Earth II map from http://www.shadedrelief.com/natural2/. The map http://www.nacis.org/data/NE2/NE2_land_only.jpg is 16200x8100 pixels, plate caree, WGS84. It also has a world file http://www.shadedrelief.com/natural2/images/world_16000.zip with following information. 0.02 0.00 0.00 -0.02 -180.00 90.00 Alex, The world file name must follow the conventions. If your file is called NE2_land_only.jpg than the world file name must be either NE2_land_only.jgw or NE2_land_only.wld And, humm, there is much sea water on that ..._land_only image Joaquim Luis ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] help with gdalwarp
On Sun, Jan 4, 2009 at 11:00 PM, Joaquim Luis jl...@ualg.pt wrote: Alex, The world file name must follow the conventions. If your file is called NE2_land_only.jpg than the world file name must be either NE2_land_only.jgw or NE2_land_only.wld Joaquim, renaming the world file to NE2_land_only.jgw was one of first things I've done, sorry I forgot to mention that. So it's not reason for the problems I'm having with reprojection. The coordinates in world file are specified in degrees, is this how it supposed to be, or do I need to pass any switches to gdalwarp to indicate that? ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] help with gdalwarp
Alex Bernstein wrote: On Sun, Jan 4, 2009 at 11:00 PM, Joaquim Luis jl...@ualg.pt wrote: Joaquim, renaming the world file to NE2_land_only.jgw was one of first things I've done, sorry I forgot to mention that. So it's not reason for the problems I'm having with reprojection. The coordinates in world file are specified in degrees, is this how it supposed to be, or do I need to pass any switches to gdalwarp to indicate that? Alex, Sorry, I don't know. Normally Lambert Azimuthal Equal Area should take two standard parallels, but it makes no difference here. I tried gdalwarp -s_srs +proj=eqc +lat_ts=0 +lon_0=0 +datum=WGS84 -t_srs +proj=laea +lat_1=20n +lat_2=60n -co TFW=YES NE2_land_only.jpg NE2_land_only_laea.tif which reports ... Upper Left (-180.011, 89.4085425) ( 0d 0'5.82W, 0d 0'2.91N) Lower Left (-180.011, -89.3968263) ( 0d 0'5.82W, 0d 0'2.91S) Upper Right ( 179.9964220, 89.4085425) ( 0d 0'5.82E, 0d 0'2.91N) Lower Right ( 179.9964220, -89.3968263) ( 0d 0'5.82E, 0d 0'2.91S) Center ( -0.0073446, 0.0058581) ( 0d 0'0.00W, 0d 0'0.00N) but the file is not reprojected either. I don't know if it is related but I found many instances where gdalwarp fails on global files. I reported that twice, last one on ticket http://trac.osgeo.org/gdal/ticket/2305 but unfortunately it didn't deserve any attention. ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] help with gdalwarp
Joaquim, Thanks for trying to help. I'm actually just interested in the map of Africa from this global map. May be I'll try to figure out gdal commands to crop and transform just the relevant region. --Alex On Mon, Jan 5, 2009 at 1:05 AM, Joaquim Luis jl...@ualg.pt wrote: Alex Bernstein wrote: On Sun, Jan 4, 2009 at 11:00 PM, Joaquim Luis jl...@ualg.pt wrote: Joaquim, renaming the world file to NE2_land_only.jgw was one of first things I've done, sorry I forgot to mention that. So it's not reason for the problems I'm having with reprojection. The coordinates in world file are specified in degrees, is this how it supposed to be, or do I need to pass any switches to gdalwarp to indicate that? Alex, Sorry, I don't know. Normally Lambert Azimuthal Equal Area should take two standard parallels, but it makes no difference here. I tried gdalwarp -s_srs +proj=eqc +lat_ts=0 +lon_0=0 +datum=WGS84 -t_srs +proj=laea +lat_1=20n +lat_2=60n -co TFW=YES NE2_land_only.jpg NE2_land_only_laea.tif which reports ... Upper Left (-180.011, 89.4085425) ( 0d 0'5.82W, 0d 0'2.91N) Lower Left (-180.011, -89.3968263) ( 0d 0'5.82W, 0d 0'2.91S) Upper Right ( 179.9964220, 89.4085425) ( 0d 0'5.82E, 0d 0'2.91N) Lower Right ( 179.9964220, -89.3968263) ( 0d 0'5.82E, 0d 0'2.91S) Center ( -0.0073446, 0.0058581) ( 0d 0'0.00W, 0d 0'0.00N) but the file is not reprojected either. I don't know if it is related but I found many instances where gdalwarp fails on global files. I reported that twice, last one on ticket http://trac.osgeo.org/gdal/ticket/2305 but unfortunately it didn't deserve any attention. ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] help with gdalwarp
Alex Bernstein wrote: Joaquim, Thanks for trying to help. I'm actually just interested in the map of Africa from this global map. May be I'll try to figure out gdal commands to crop and transform just the relevant region. That will work fine. I just tried with Mirone and checked against GMT coastlines and the result is quite satisfactory. ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] help with gdalwarp
Seems to have worked! I used: gdal_translate -a_srs +proj=longlat +datum=wgs84 -projwin -30 45 60 -45 -co TFW=YES -co INTERLEAVE=PIXEL -of Gtiff source_images\NE2_land_only.jpg test.tif gdalwarp -t_srs +proj=laea +lat_0=0 +lon_0=15 +x_0=0 +y_0=0 -r lanczos -co INTERLEAVE=PIXEL -co TFW=YES -of GTiff test.tif test2.tif The result looks like LAEA. I needed to change projection to make it match another map that I had. Will check how good the map is now. --Alex ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
