[Proj] looking for the right params for RSO
Hermann Peifer
peifer at gmx.eu
Sun Aug 29 11:32:08 EST 2010
On 27/08/2010 08:57, Christoph Dohmen wrote:
> Hi list,
>
> I'm searching for the right parameter set for RSO projected coordinates.
>
> Given a dedicated point from google earth with lat-long = 100.563743E 5.389524N
>
> Having a raster dataset with a projection set as the following:
>
> PROJCS["Kertau_RSO_Malaya_Meters",
> GEOGCS["GCS_Kertau",
> DATUM["D_Kertau",
> SPHEROID["Everest_1830_Modified",6377304.063,300.8017]],
> PRIMEM["Greenwich",0.0],
> UNIT["Degree",0.0174532925199433]],
> PROJECTION["Rectified_Skew_Orthomorphic_Natural_Origin"],
> PARAMETER["False_Easting",804671.299775],
> PARAMETER["False_Northing",0.0],
> PARAMETER["Scale_Factor",0.99984],
> PARAMETER["Azimuth",-36.97420943711801],
> PARAMETER["Longitude_Of_Center",102.25],
> PARAMETER["Latitude_Of_Center",4.0],
> PARAMETER["XY_Plane_Rotation",-36.86989764584402],
> UNIT["Meter",1.0]]
>
> Inside the dedicated point has the coordinates 286400m east 596700m north.
>
> Now I want to set up a translation first via proj directly and later on
> for a gdal-warp to transform the rasterdataset.
>
> I tried out the parameter:
>
> cs2cs +init=epsg:4326 +to +proj=omerc +a=6377304.063 +rf=300.8017 +lat_0=4.0 +lonc=102.25 +alpha=323.025790562881987 +gamma=323.13010235415598 +k_0=0.99984 +x_0=804671.299775
>
> but the result is 617824.69 153846.36
>
You are getting somewhat closer to the expected result with:
cs2cs -v +init=epsg:4326 +to +proj=omerc +a=6377304.063 +rf=300.8017
+lat_0=4.0 +lonc=102.25 +alpha=323.025790562881987 +k_0=0.99984
+x_0=804671.299775 +no_uoff +rot_conv
286289.13 596607.56 0.00
You might have to look for appropriate towgs84 parameter values.
Hermann
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