There is no way to disable these labels as part of the RM export, but there are a few ways you could achieve it.
I think the easiest way would be to edit the KML file once it has already been exported. This is a little trickier than it could be because Google Earth files are exported as KMZ files, which are basically zipped KML files. What you will need to do is the following (all of this assumes that you are making your exports directly from an RM map project, and not a user map):
- Export your map to a GE KMZ file, and open it in Google Earth.
- Right-click the map in the GE "Places" list at the left of the GE window, and choose "save place as". Change the format to KML and choose a filename.
- You will end up with a KML file with all of your map components in, which is a text file that can be edited in Notepad or similar text editing software.
Open the KML file and look for the following snippet - it is the style that is defined for the Major contours layer, and has a field called
labelVisibility. Either delete this entire tag (everything in bold, below), or replace the 1 with a 0.
Now save the file and reopen in GE. Your labels should be gone (make sure you are not also displaying the original file at the same time).
Unfortunately it isn't possible to set the label visibilty tag for a layer within GE itself.
<Document>
<name>Major contours</name>
<Style id="contourcolor">
<LineStyle>
<color>ff262626</color>
<gx:labelVisibility>1</gx:labelVisibility>
</LineStyle>
</Style>