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I'm trying to get the extent of a MIF file using ogrinfo. The MIF file is supposed to be in epsg:23030 projection. This is:

PROJCS["ED50 / UTM zone 30N",
    GEOGCS["ED50",
        DATUM["European_Datum_1950",
            SPHEROID["International 1924",6378388,297,
                AUTHORITY["EPSG","7022"]],
            AUTHORITY["EPSG","6230"]],
        PRIMEM["Greenwich",0,
            AUTHORITY["EPSG","8901"]],
        UNIT["degree",0.01745329251994328,
            AUTHORITY["EPSG","9122"]],
        AUTHORITY["EPSG","4230"]],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["central_meridian",-3],
    PARAMETER["scale_factor",0.9996],
    PARAMETER["false_easting",500000],
    PARAMETER["false_northing",0],
    AUTHORITY["EPSG","23030"],
    AXIS["Easting",EAST],
    AXIS["Northing",NORTH]]

But with ogrinfo, I get this as SRS WKT

PROJCS["unnamed",
    GEOGCS["unnamed",
        DATUM["European_Datum_1950",
            SPHEROID["International 1924",6378388,297],
            TOWGS84[-87,-98,-121,-0,-0,-0,0]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["central_meridian",-3],
    PARAMETER["scale_factor",0.9996],
    PARAMETER["false_easting",500000],
    PARAMETER["false_northing",0],
    UNIT["Meter",1]]

And this as extent

Extent: (-28050.000000, 3896708.000000) - (1139100.000000, 4874250.000000)

Outside the limits of epsg:23030 projection, and with negative coordinates.

I don't know if it's related, but the data file covers all Spain, and epsg:23030 doesn't cover all the country. There's a small part covered by epsg:23029. So, I guess the problem is related with the way the file was exported or georeferenced in the origin (MapInfo).

So, what could be the problem with my data?

2

If the data should cover whole of Spain, I see no problem with the negative coordinate.

You will get more distorsions at the edges, but the map should work, until you don't have points on the backside of the globe. This should be the map extent, together with the UTM zones:

enter image description here

The extent covers UTM zones 29 to 31, so UTM zone 30 is a good choice for a country-wide map.

  • Thanks! Just a question: how did you get that red polygon? I guess you used the TOWGS84 parameters and the extent coordinates. – Jorge Arévalo Mar 10 '14 at 19:25
  • The yellow points are your extent coordinates in EPSG:23030. I just joined them with a polygon. – AndreJ Mar 10 '14 at 20:14

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