[mapserver-users] Projections and raster files

[David Power]

Hello,

I have a number of geotiffs which are currently using epsg:4326 and I would like to output a region using epsg:3857.

I am new to mapserver but from what I have read the way achieve this is by setting the projection of the map to epsg:3857 and the layer to epsg:4326.

When I set the projections to the same value I get the output I expect without a problem, if I set the projections to different values I do not get an error but the output is blank.

To make life more complicated I am using mapscript via the Java swig interface, the version of mapserver I am using is mapserver 6.1.2.1 which I built from source.

If anybody has any advice I would be most grateful.

David

- 

gdalinfo gives the following information about one of the files:

Driver: GTiff/GeoTIFF
Files: globcover_n10e005.tif
Size is 7200, 7200
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"]]
Origin = (5.000000000000000,9.999999999999615)
Pixel Size = (0.000138888888889,-0.000138888888889)
Metadata:
  DataType=Generic
  AREA_OR_POINT=Area
Image Structure Metadata:
  INTERLEAVE=BAND
Corner Coordinates:
Upper Left  (   5.0000000,  10.0000000) (  5d 0'0.00"E, 10d 0'0.00"N)
Lower Left  (   5.0000000,   9.0000000) (  5d 0'0.00"E,  9d 0'0.00"N)
Upper Right (   6.0000000,  10.0000000) (  6d 0'0.00"E, 10d 0'0.00"N)
Lower Right (   6.0000000,   9.0000000) (  6d 0'0.00"E,  9d 0'0.00"N)
Center      (   5.5000000,   9.5000000) (  5d30'0.00"E,  9d30'0.00"N)
Band 1 Block=7200x128 Type=Byte, ColorInterp=Gray
  NoData Value=0

-

The map file is built programmatically, the following is the result of saving the map object to file:

MAP
  EXTENT 5 9.9 5.1 10
  IMAGETYPE "png"
  NAME "blank"
  SIZE 800 800
  STATUS ON
  UNITS DD

  OUTPUTFORMAT
    NAME "png"
    MIMETYPE "image/png"
    DRIVER "AGG/PNG"
    EXTENSION "png"
    IMAGEMODE RGB
    TRANSPARENT FALSE
  END # OUTPUTFORMAT

  PROJECTION
    "init=epsg:3857"
  END # PROJECTION
  LEGEND
    KEYSIZE 20 10
    KEYSPACING 5 5
    LABEL
      SIZE MEDIUM
      OFFSET 0 0
      SHADOWSIZE 1 1
      TYPE BITMAP
    END # LABEL
    STATUS OFF
  END # LEGEND

  QUERYMAP
    SIZE -1 -1
    STATUS OFF
    STYLE HILITE
  END # QUERYMAP

  SCALEBAR
    INTERVALS 4
    LABEL
      SIZE MEDIUM
      OFFSET 0 0
      SHADOWSIZE 1 1
      TYPE BITMAP
    END # LABEL
    SIZE 200 3
    STATUS OFF
    UNITS MILES
  END # SCALEBAR

  WEB
  END # WEB

  LAYER
    DATA "/home/leftworker/data/landcover/lefttiles/n10/globcover_n10e005.tif"
    NAME "n10e005"
    PROJECTION
      "init=epsg:4326"
    END # PROJECTION
    STATUS ON
    TILEITEM "location"
    TYPE RASTER
    UNITS DD
  END # LAYER

END # MAP





======================================
Dr David J Power
Research Officer
Department of Computer Science
University of Oxford
tel:   01865 283670
email: David.Power at cs.ox.ac.uk
======================================



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