I am trying to use Cesium.Polyline to draw a route on a 3D terrain, filling in the elevation values from my dataset (NED 1/3 arc second). I’m noticing occasional gross misalignment, even when looking “straight down”. I have high confidence in the route waypoint coordinates as they line up perfectly with OpenLayers and Google maps (2D).
What could I be doing wrong? Could this be caused by inaccuracies in tile re-projection or differences between my elevation data and yours? I would think that if the only error was elevation differences, it would be evident in the shape of the polyline – it would end up directly above or directly below the road, but still vertically aligned. So I’m led to believe that there’s projection issues. How would I go about debugging this?