1

I need to reproject several GEOTIFF tiles(each having different height/width) in six different UTM zones from UTM to Plate Carree.

Output of gdalinfo of two sample tiles is enclosed. As is clearly seen they are the same type of projection but different UTM zone hence they are not the same projection. What I have been thinking of doing is reproject tiles from the other UTM zones to the tile of the first UTM zone and then mosaic all the tiles and then reproject to Plate Carree. I already have GIS software to do the reprojection and so my question relates to the validity of the approach. Will this give the best result or are there other approaches that will give better results?

My ultimate goal is to cut tiles from the mosaic in such a way that height equals width.

Coordinate System is: PROJCS["WGS 84 / UTM zone 42N", 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"]], PROJECTION["Transverse_Mercator"], PARAMETER["latitude_of_origin",0], PARAMETER["central_meridian",69], PARAMETER["scale_factor",0.9996], PARAMETER["false_easting",500000], PARAMETER["false_northing",0], UNIT["meters",1], AUTHORITY["EPSG","32642"]]

and 2nd tile -

Coordinate System is: PROJCS["WGS 84 / UTM zone 43N", 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"]], PROJECTION["Transverse_Mercator"], PARAMETER["latitude_of_origin",0], PARAMETER["central_meridian",75], PARAMETER["scale_factor",0.9996], PARAMETER["false_easting",500000], PARAMETER["false_northing",0], UNIT["meters",1], AUTHORITY["EPSG","32643"]]

  • 2
    Personally I would prefer a reprojection into a geodetic date with less distortion. So 1. all into latlong (epsg 4326), 2. mosaic, 3. reprojection to plate carree and 4. finally your tiling. – jejune Jun 14 '15 at 21:40
  • I'm not really sure. Maybe it is another term I don't know. If it is the same skip step 3. If not put whatever datum you need in point 3. – jejune Jun 15 '15 at 6:05
  • @handgun maybe you find an epsg code for your plate caree? Than we could find out. – jejune Jun 15 '15 at 8:03
  • Damn autocomplete. @gansub – jejune Jun 15 '15 at 8:04
  • 1
    plate carre <> (!=) 4326. When lat/lon values are displayed as a 2D map, the angular values are treated as if they're linear. Plate Carree converts degrees to radians and scales them by the semimajor axis of the ellipsoid or radius of the sphere being used. – mkennedy Jun 15 '15 at 17:52
2

Sorry. Some days without inet. So:

  1. reprojection into latlong (epsg 4326) or something adequate for the region's extent (otherwise it looks like Kandinsky),
  2. mosaic,
  3. reprojection to put favorite projection here and finally
  4. do your tiling.

Enjoy.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.