If you have longitude and latitude for your nodes or groups defined as custom properties, you can use the coordinates to automatically place the nodes on the WorldWide Map.
If the box is selected, only the data you changed manually in the exported file will be imported. After an automatic export, there are no changes, and thus no data will be imported.
The values for Longitude (World Map) should match the Longitude values, and values for Latitude (World Map) should match the Latitude values.
You can now see the nodes in the Woldwide Map, as specified by the Longitude and Latitude (World Map) properties.