HOW TO: Advanced Geolocation Features in udStream

HOW TO: Advanced Geolocation Features in udStream

udStream and Geolocation

udStream by default supports a list of EPSG/SRID and support for more EPSG codes are added with each release. However, should you have an EPSG code that is not supported, you can try adding in its Well-Known-Text (WKT).


Well-Known-Text or WKT is text markup language that represents spatial reference systems of spatial objects and transformations between these systems. udStream uses WKTs to place your datasets in the right place of the map.

Before Starting

Before trying to use a WKT, check for the Spheroid Type (labelled SPHEROID) and Geodetic Datum (labelled GEOGCS) against the supported list in the table below:
WGS 84
WGS 84
Airy 1830 
Airy Modified 1849 
Bessel 1841
Clarke 1866
Clarke 1880 (IGN)
GRS 1980
International 1924
WGS 72
OSGB 1936
PD / 83
Clarke 1858
Clarke 1880 (international foot)
WGS 72
Krassowsky 1940
Everest 1830 Modified




Hong Kong 1980








Singapore Grid

Mars 2000

Moon 2000

Overriding Geolocation with WKT

This assumes that you have converted your file to UDS

  1. Open udStream and load your dataset/s
  2. Under Edit > Preferences/Settings, Tick on Show Projection Information 

  3. Select Close. Go back to the Scene, an option to Edit Spatial Reference will appear

4. Copy the WKT in and click Apply:

Click on Close. In the Scene Explorer, right-click on your dataset and select Reset Transform
5. To verify if the model has loaded in right location, Add a Map Tile:

Converting to UDS with Custom WKT

Once you verified that the file geolocates at the correct place, You can convert the file with the custom WKT embedded. To do this, you can follow the standard way of converting here then follow the steps below:

  1. In the Convert window, tick on Override Geolocation.

  2. An option to Edit Spatial Reference will appear

  3. Copy the WKT in AND change the very bottom text to AUTHORITY["EPSG","1"]]:

4. Click Apply then Click Convert
5. To verify, load in the converted file into Scene. It should be in the right position
IMPORTANT: udStream supports WKT in both HTML and Esri formats. For more information, you can check out and select the right format

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