ED50 to WGS84

OK, I'm not really a GIS person, so I may be asking something daft; but anyway.

I only use GM for converting map types. We have an RF planning tool which parses a limited set of file formats, mainly USGS DEM, and I use GM to convert whatever the customer gives us to that file format.

However, I have been given a 1m resolution map of Malta using UTM Zone 33 projection and ED50 datum. GM loads this fine, but when I export the data set as USGS DEM I still have the coordinates in metres which confuses the RF planning tool as it is looking for lat/lon and also, in the DEM file header there is no reference to the Datum, so it wouldn't know how to convert the data into Lat/Lon. (It doens't parse a projection file, it just expects WGS84).

So, can I use GM to do the conversion and export the data as Lat/Lon (WGS84 projection)? The map files are several GB in size, so I'm looking for a built in conversion. My fall back is I write my own file parser to open the UTM33/ED50 DEM and convert 5Gb of coords to WGS84; but that's a load of work I don't really want...




  • You can reproject the data using File > Batch Convert/Reproject...

    Alternatively you can set the workspace as Geographic (Latitude/Longitude) via Tools > Configure > Projection and when importing the data specify the projection for the incoming file e.g. Projection: UTM; Zone: 33 North; Datum: ED50 (MALTA). Check that the projection of your workspace is still Geographic (Latitude/Longitude) before you export the data as GM uses the workspace projection when exporting.
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