Opened 11 years ago

Closed 10 years ago

#2744 closed defect (fixed)

EPSG:3388 Projection Parameter incorectly set to Mercator_1SP

Reported by: crschmidt Owned by: warmerdam
Priority: normal Milestone:
Component: OGR_SRS Version: svn-trunk
Severity: normal Keywords: Mercator2SP
Cc:

Description (last modified by warmerdam)

From http://lists.osgeo.org/pipermail/metacrs/2008-December/000185.html:

  • EPSG:3388, Pulkovo 1942 / Caspian Sea Mercator

According to EPSG, the projection method is "Mercator (2SP)", coord op method 9805, with a standard parallel at 42?N. But on SpatialReference?.org, the projection method in OGC WKT is given as "Mercator_1SP", and the standard parallel is absent from the parameters.

Change History (1)

comment:1 Changed 10 years ago by warmerdam

Description: modified (diff)
Keywords: Mercator2SP added
Resolution: fixed
Status: newclosed

Corrected handling of Mercator2SP (9805) in ogr_fromepsg.cpp in trunk (r18979). With this change 3388 expands as:

PROJCS["Pulkovo 1942 / Caspian Sea Mercator",
    GEOGCS["Pulkovo 1942",
        DATUM["Pulkovo_1942",
            SPHEROID["Krassowsky 1940",6378245,298.3,
                AUTHORITY["EPSG","7024"]],
            TOWGS84[23.92,-141.27,-80.9,-0,0.35,0.82,-0.12],
            AUTHORITY["EPSG","6284"]],
        PRIMEM["Greenwich",0,
            AUTHORITY["EPSG","8901"]],
        UNIT["degree",0.01745329251994328,
            AUTHORITY["EPSG","9122"]],
        AUTHORITY["EPSG","4284"]],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]],
    PROJECTION["Mercator_2SP"],
    PARAMETER["standard_parallel_1",42],
    PARAMETER["central_meridian",51],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",0],
    AUTHORITY["EPSG","3388"],
    AXIS["none",NORTH],
    AXIS["none",EAST]]

and translates to PROJ.4 as:

+proj=merc +lon_0=51 +lat_ts=42 +x_0=0 +y_0=0 
           +ellps=krass  +towgs84=23.92,-141.27,-80.9,-0,0.35,0.82,-0.12 
           +units=m +no_defs 

It would be desirable to have a known test point for 3388. Note this change also corrects the interpretation of EPSG:3994 WGS/Mercator41.

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