6

Given a PROJCS data

PROJCS["unnamed",
    GEOGCS["WGS 84",
        DATUM["WGS_1984",
            SPHEROID["WGS 84",6378137,298.257223560493,
                AUTHORITY["EPSG","7030"]],
            AUTHORITY["EPSG","6326"]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433],
        AUTHORITY["EPSG","4326"]],
    PROJECTION["Lambert_Conformal_Conic_2SP"],
    PARAMETER["standard_parallel_1",-25.91105555555576],
    PARAMETER["standard_parallel_2",-32.72172222222201],
    PARAMETER["latitude_of_origin",-29.51611111111111],
    PARAMETER["central_meridian",-52.09266666666708],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (-725301.460735953995027,572835.914701772970147)
Pixel Size = (169.335263023642995,-169.335263023642995)

How do I find the actual projection name? I can see EPSG:7030, EPSG:6326, EPSG:4326 and EPSG:9001. What is the actual EPSG:xxxx of this projection?

Comparing to the known EPSG:900913 I can conclude the last AUTHORITY is naming the Projection:

PROJCS["WGS84 / Google Mercator", 
  GEOGCS["WGS 84", 
    DATUM["World Geodetic System 1984", 
      SPHEROID["WGS 84", 6378137.0, 298.257223563, AUTHORITY["EPSG","7030"]], 
      AUTHORITY["EPSG","6326"]], 
    PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]], 
    UNIT["degree", 0.017453292519943295], 
    AXIS["Longitude", EAST], 
    AXIS["Latitude", NORTH], 
    AUTHORITY["EPSG","4326"]], 
  PROJECTION["Mercator_1SP"], 
  PARAMETER["semi_minor", 6378137.0], 
  PARAMETER["latitude_of_origin", 0.0], 
  PARAMETER["central_meridian", 0.0], 
  PARAMETER["scale_factor", 1.0], 
  PARAMETER["false_easting", 0.0], 
  PARAMETER["false_northing", 0.0], 
  UNIT["m", 1.0], 
  AXIS["x", EAST], 
  AXIS["y", NORTH], 
  AUTHORITY["EPSG","900913"]]

Is this correct? So my example will be EPSG:9001?

I'm in troble to create a layer in my geoserver using a GeoTIFF with this projection. While I can preview the layer fine, I can't put it to work in a real map or grouping with other layers. It always go to 0,0

3

As you see from the brackets, the EPSG:9001 is only valid for the UNIT variable.

Generally, a data distributor can set up CRS parameters as he wants to. Some of them are in the EPSG database (mostly those that are used for surveying), and they have an EPSG code number. But you have to accept that a CRS can not be represented by an EPSG code.

If you work with PROJ.4/GDAL based software, you might want the proj.4 definition from the WKT. You can get that if you put the WKT in a text file, and run gdalsrsinfo on that.

You will receive:

 PROJ.4 : '+proj=lcc +lat_1=-25.91105555555576 +lat_2=-32.72172222222201 +lat_0=-29.51611111111111 +lon_0=-52.09266666666708 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs '

You can create a custom CRS with that string, and work with that. http://docs.geoserver.org/2.7.1/user/advanced/crshandling/customcrs.html gives the instructions for doing that in Geoserver.

  • Ok. I'm in troble to create a layer in my geoserver using a GeoTIFF with this projection. While I can preview the layer fine, I can't put it to work in a real map or grouping with other layers. It always go to 0,0 ... What can I do? – Magno C Jul 29 '16 at 16:03
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    You might reproject the file to another CRS like UTM using gdalwarp and feed that to the Geoserver. Or define a custom CRS with your own srid ("EPSG code"), see docs.geoserver.org/2.7.1/user/advanced/crshandling/… – AndreJ Jul 29 '16 at 16:08
  • gdalwarp is asking me for the source srid and I don't know what to give: gdalwarp -rc -s_srs **epsg:WHAT?** -t_srs epsg:900913 -dstnodata 0 -of GTiff -co tiled=yes <SRC> <TRGT> – Magno C Jul 29 '16 at 16:20
  • 1
    Worked with -t_srs epsg:4326. – Magno C Jul 29 '16 at 19:22
  • 1
    I guess because EPSG:900913 is outdated, EPSG:3857 should be used instead. – AndreJ Jul 30 '16 at 6:46

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