ArcGIS Elevation and Z Coordinate

2018-03-12 20:26:46

I have standalone application (ArcObjects C# 10.3) uses axSceneControl, I'm trying to get a mouse click point:

private void M_axSceneControl_MouseDown(object sender, ISceneControlEvents_OnMouseDownEvent e)

{

var m_pSG = m_axSceneControl.SceneGraph;

var m_pSW = m_pSG.ActiveViewer;

object a1;

object b;

IPoint pt;

m_pSG.Locate(m_pSW, e.x, e.y, esriScenePickMode.esriScenePickGraphics, true, out pt, out a1, out b);

}

The point is under the mouse pointer with the filled Z coordinate.

But if you get the height at the specified point pt through the

function ISurface.GetElevation(pt.x, pt.y), (IRasterSurface, ZFactor 0.001). I get a value close to Z but not exactly accurate.

X=78.2967, Y=31.8368, Z=2.2807; Elevation=5159.5076

X=77.3918, Y=32.6779, Z=2.2474; Elevation=5732.2082

X=73.3516, Y=30.4610, Z=-0.0559; Elevation=151.3352

X=71.7634, Y=29.0155, Z=-0.0909; Elevation=114.8338

why is this happening ?