Rectified Skew Orthomorphic (RSO) Borneo map projection system used by the Department of Lands and Surveys, Sarawak has 2,000,000 m and 5,000,000 m defined as the False Easting and False Northing respectively in the projection parameters; otherwise the Easting and Northing coordinates enter into negative values in the western most region of Sarawak, i.e. somewhere beyond Sematan area of Lundu district. Negative coordinates values are less flavourable for the purpose of coordinates computation and cadastral mapping.
In ArcGIS (9.0 above), this map projection can be created easily by modifying from the existing projection file "Timbalai 1948 RSO Borneo Meters.prj" as in the following example:
Note that ESRI only support this map projection system from ArcGIS 9.0 onwards.
Once the above projection file is defined, it is easy to integrate map data from other Coordinate Reference Systems into the Department's geodatabases. Example of common translations available for this region are:
The RSO Borneo (metres, Code EPSG::29873) on EPSG Registry (http://www.epsg-registry.org/). is based on EPSG Code:9815 Hotine Oblique Mercator (variant B), of which the final rotation is applied to the center of projection at
Easting 590476.87 m
Northing 442857.65 m
As such, the modified version of the RSO Borneo projection parameters using EPSG:9812 Hotine Oblique Mercator (Variant A) (where the final rotation applied is at the natural origin) should look like this:
| Latitude of projection centre | 4 | sexagesimal DMS | |
| Longitude of projection centre | 115 | sexagesimal DMS | |
| Azimuth of initial line | 53° 18' 56.9537" | sexagesimal DMS | |
| Angle from Rectified to Skew Grid | 53° 7' 48.3685" | sexagesimal DMS | |
| Scale factor on initial line | 0.99984 | unity | |
| False easting | 2,000,000 | metre | |
| False northing | 5,000,000 | metre |
In ArcGIS (9.0 above), this map projection can be created easily by modifying from the existing projection file "Timbalai 1948 RSO Borneo Meters.prj" as in the following example:
File: Coordinate Systems\Projected Coordinate Systems\National Grids\Malaysia\Timbalai 1948 RSO Borneo Meters LnS Sarawak.prj
PROJCS["Timbalai_1948_RSO_Borneo_Meters",GEOGCS["GCS_Timbalai_1948",DATUM["D_Timbalai_1948",SPHEROID["Everest_Definition_1967",6377298.556,300.8017]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Rectified_Skew_Orthomorphic_Natural_Origin"],PARAMETER["False_Easting",2000000.0],PARAMETER["False_Northing",5000000.0],PARAMETER["Scale_Factor",0.99984],PARAMETER["Azimuth",53.31582047908623],PARAMETER["Longitude_Of_Center",115.0],PARAMETER["Latitude_Of_Center",4.0],PARAMETER["XY_Plane_Rotation",53.13010235415598],UNIT["Meter",1.0]]
Note that ESRI only support this map projection system from ArcGIS 9.0 onwards.
Once the above projection file is defined, it is easy to integrate map data from other Coordinate Reference Systems into the Department's geodatabases. Example of common translations available for this region are:
- Geographic coordinates, WGS 84 datum (i.e. GPS data) <=> RSO Borneo LnS (Timbalai 1948 datum)
- UTM Zone49N, Zone50N, WGS 84 datum <=> RSO Borneo LnS (Timbalai 1948 datum)
The RSO Borneo (metres, Code EPSG::29873) on EPSG Registry (http://www.epsg-registry.org/). is based on EPSG Code:9815 Hotine Oblique Mercator (variant B), of which the final rotation is applied to the center of projection at
Easting 590476.87 m
Northing 442857.65 m
thank you for this ... was very helpful!!!
ReplyDeletehow can we adopt/create this into FOSS i.e. QGIS in Proj4 format?
ReplyDeletehi,
DeleteTested with QGIS 1.8 lisboa, I believe the Custom CRS parameters should be
+proj=omerc +lat_0=4 +lonc=115 +alpha=53.31582047222222 +gamma=53.13010236111111 +k=0.99984 +x_0=2000000 +y_0=5000000 +no_uoff +ellps=evrstSS +towgs84=-533.4,669.2,-52.5,0,0,4.28,9.4 +units=m +no_defs.
The test result of point conversion from WGS 84 coordinates to this custom CRS using QGIS matched well with the result from ArcGIS 10.
However, it seems that QGIS/Proj.4 is not able to handle the on-the-fly reprojection of this CRS. It does not display data sets in WGS 84 or Borneo RSO Meters (EPSG 29873) correctly when the project CRS is set to this custom CRS.
See also
http://osgeo-org.1560.n6.nabble.com/RSO-gamma-and-Hotine-Oblique-Mercator-Variant-A-td3841370.html
http://georepository.com/crs_29873/Timbalai-1948-RSO-Borneo-m.html
http://georepository.com/projection_19894/Borneo-RSO.html
thanks for reply, how do u create the ArcGIS projection into proj4 string?
DeletePROJCS["Timbalai_1948_BRSO_Borneo_Meters",GEOGCS["GCS_Timbalai_1948",DATUM["D_Timbalai_1948",SPHEROID["Everest_Definition_1967",6377298.556,300.8017]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Rectified_Skew_Orthomorphic_Natural_Origin"],PARAMETER["False_Easting",2000000.0],PARAMETER["False_Northing",5000000.0],PARAMETER["Scale_Factor",0.99984],PARAMETER["Azimuth",53.31582047908623],PARAMETER["Longitude_Of_Center",115.0],PARAMETER["Latitude_Of_Center",4.0],PARAMETER["XY_Plane_Rotation",53.13010235415598],UNIT["Meter",1.0]],VERTCS["WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PARAMETER["Vertical_Shift",0.0],PARAMETER["Direction",1.0],UNIT["Meter",1.0]]