# 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 | Notes
--- | --- | --- | --- | --- | ---
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.