Swiss Oblique Cylindrical

Name	Swiss Oblique Cylindrical
Alias	Swiss Oblique Mercator
EPSG Code	9814
GeoTIFF Code	CT_SwissObliqueCylindrical (5)
OGC WKT Name	Swiss_Oblique_Cylindrical
Supported By	EPSG, GeoTIFF, OGC WKT

Projection Parameters

Name	EPSG #	GeoTIFF ID	OGC WKT	Units
Latitude of projection center	1	CenterLat	latitude_of_origin	Angular
Longitude of projection center	2	CenterLong	central_meridian	Angular
False Easting	6	FalseEasting	false_easting	Linear
False Northing	7	FalseNorthing	false_northing	Linear

Notes

The GeoTIFF geo_ctrans.inc file shows that CT_SwissObliqueCylindrical is an alias for CT_ObliqueMercator_Rosenmund, but the EPSG database says that it is accomodated by the Oblique Mercator method (9815). I am not sure what to make of all this. CT_ObliqueMercator_Rosenmund does not seem to be a supported method in EPSG.

In MapInfo this is projection 25, and is called Swiss Oblique Mercator.

If this is mapped onto Hotine Oblique Mercator, it isn't obvious to me what the settings for Azimuth, Angle from rectified grid, and scale at center should be ... likely 90, 90 and 1.0.

Detailed information is available from:

ftp://ftp.swisstopo.ch/pub/data/geo/refsyse.pdf

OGC WKT Variations

GDAL/OGR Well Known Text representation for a Swiss Oblique Mercator coordinate system:

PROJCS["CH1903+ / LV95",
    GEOGCS["CH1903+",
        DATUM["CH1903",
            SPHEROID["Bessel 1841",6377397.155,299.1528128],
            TOWGS84[674.374,15.056,405.346,0,0,0,0]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.01745329251994328]],
    PROJECTION["Hotine_Oblique_Mercator"],
    PARAMETER["latitude_of_center",46.95240555555556],
    PARAMETER["longitude_of_center",7.439583333333333],
    PARAMETER["azimuth",90],
    PARAMETER["rectified_grid_angle",90],
    PARAMETER["scale_factor",1],
    PARAMETER["false_easting",2600000],
    PARAMETER["false_northing",1200000],
    UNIT["metre",1]]

The corresponding ESRI WKT definition follows. Nnote no rectified_grid_angle is provided and the alternate name for the projection.

PROJCS["CH1903+_LV95",
    GEOGCS["GCS_CH1903+",
        DATUM["D_CH1903+",
            SPHEROID["Bessel_1841",6377397.155,299.1528128]],
        PRIMEM["Greenwich",0],
        UNIT["Degree",0.017453292519943295]],
    PROJECTION["Hotine_Oblique_Mercator_Azimuth_Center"],
    PARAMETER["False_Easting",2600000],
    PARAMETER["False_Northing",1200000],
    PARAMETER["Scale_Factor",1],
    PARAMETER["Azimuth",90],
    PARAMETER["Longitude_Of_Center",7.439583333333333],
    PARAMETER["Latitude_Of_Center",46.95240555555556],
    UNIT["Meter",1]]

EPSG Notes

Detailed notes on Swiss Oblique Mercator and related projection methods can be found in section 1.4.7 of the EPSG Guidance Note # 7. However, in practice, now all swiss oblique mercator coordinate systems in EPSG are handled as Hotine Oblique Mercator with an azimuth of 90 and a rectified grid angle of 90.