Query elevation without displaying elevation layer
I have an elevation layer that is created from a vrt file containing DTED elevation data. I add this layer to my Map, but I don't want the map to actually display the bulging out terrain. Therefore, I set the layer's visibility to false. I don't want it displayed, but I do want my elevation queries to still work properly. Is there a way to achieve this using anything convenient in osgEarth?
Essentially, I am only loading 9 tiles of DTED at any given time out of hundreds (each 1 lat long in size). As I pan around, I add and remove tiles that are around my current viewpoint. If I add and remove the elevation layers, I get a blinking effect (probably because of the refresh function being called whenever an elevation layer is added to the map or removed from the map). I want to be able to prevent this, so I simply removed the elevation layer but kept my hillshade and color tifs loaded in.
So, is there a way to stop the blinking effect when adding elevation layers or is there a way to grab elevation data without ever adding elevation layers / hiding elevation layers?
Edit: I am using osgEarth 2.10, and I tried both elevation query and elevation envelopes from the elevation pool attached to the map