Dem::Elevation(double _x, double _y) does not handle NoData values

Environment

• OS Version: Ubuntu 22
• Source or binary build? Binary

Description

• Expected behavior: The following call exposes information on whether the data is "NoData" values, which happens over the ocean in some terrain:
  • Dem::Elevationpublic: double Elevation(double _x, double _y);
• Actual behavior:
  • It returns a double value, which may be the NoData value. This can silently return the NoData value, and if run against physics, could be a situation where the physics mesh is in the wrong location. For a path planner, this could mean you think terrain is safe and it's ok to fly inside a body of water and not collide with it.

Steps to reproduce

I"ll find a representative dataset shortly and create a minimum reproducible example.

1. Load terrain with NoDat

Output

TBD