KML/KMZ files need to be in lat/long to open correctly in Google Earth. If your map is in lat/long coordinates, you can export directly to KML/KMZ. If your map is in coordinates other than lat/long (e.g. UTM), then what happens depends on if you have a coordinate system defined for the map or not:
- If the map is not in lat/long and you DO have a coordinate system defined for the map, then Surfer will automatically convert the coordinates to lat/long value upon export.
- If the map is not in lat/long and you DO NOT have a coordinate system defined for the map, then you will get the warning upon export that "The exported drawing contains one or more objects whose coordinates exceed the allowable range of +/-360 horizontal (longitude) units and +/-90 vertical (latitude) units..."
If you encounter this warning during export to a KML/KMZ file, you will need to define the coordinate system of the map so Surfer knows how to convert the coordinates to lat/long. To do this:
- Select Map from the Contents window.
- In the Properties window, click the Coordinate System tab.
- If you get the warning above, the coordinate system Name is most likely Unreferenced local system. If this is the case, click the Change button.
- Select the coordinate system for the map (e.g. Predefined | Projected Systems | UTM | North America | North America NAD83 UTM zone 10N) and click OK.
- In the Surfer Warning that some layers are unreferenced, click OK. This is fine.
- If desired, you can click the Assign Now button at the bottom of the Coordinate System page in the Properties window to assign the map coordinate system to all unreferenced layers in the map, but this isn’t necessary. It might be nice to do, however, if you’d ever want to convert the coordinate system of the map in the future.
- Now that the map has a coordinate system defined for it, click File | Export and export to the KML or KMZ file. Surfer will automatically convert the coordinates from the coordinate system you selected to Lat/Long upon export.
Updated September 1, 2020