LiDAR elevation check

If saved LiDAR DEMs exist on the tablet, the Survey, Grade, and Field Survey maps show a small height button above the Layers FAB — green when idle, amber while checking is active. Tap it and the Select LiDAR Source dialog opens; choose which saved DEM to use, then tap points on the map to read the LiDAR elevation there.

Use this as a field sanity check: compare a known high spot, low spot, or benchmark area against the saved LiDAR before generating contours or grading. Values display in the active unit system. If you move to another field, tap the button again and pick a different DEM source. To return map taps to normal behaviour, tap the (amber) button again and choose Stop Checking.

The button is hidden when no saved DEM exists, so it is never a live internet elevation query. If you tap a point with no data, the elevation bubble simply doesn't appear (a brief "..." may vanish) — the point is outside the selected DEM or sits on a no-data cell. A No LiDAR elevation at this point. message appears only at source-selection time, when the chosen DEM file can't be loaded or decoded.