topic Is there any way to get the Z-Coordinate when snapping? in ArcObjects SDK Questions

Is there any way to get the Z-Coordinate when snapping?

SuiHuang — Tue, 17 Sep 2013 15:28:36 GMT

Hi Everybody:

I am writing some code to do snapping. When I snap a new point (with X and Y only) to an existing point feature (with XYZ coordinates). I will get the XY of the feature that it is snapped to, but not Z. Following is my current code. Is there anyway to identify the Z coordinate of the feature? For example, find the feature that is snapped to first, and then get Z?

Thank you!

// X, Y are the mouse coordinates, get the point on the map with Lat-Long but without Z coordinate IPoint mapPoint; mapPoint = QueryMapPoint((m_application.Document as IMxDocument).ActivatedView.ScreenDisplay, X, Y);  // snap ISnappingResult snapResult = m_Snapper.FullSnap(mapPoint); if (snapResult != null) {     IPoint SnappedMousePoint = snapResult.Location;   // only get the XY, but Z=NaN }

Re: Is there any way to get the Z-Coordinate when snapping?

DuncanHornby — Wed, 18 Sep 2013 12:37:05 GMT

I have to admit I have never utilised any snapping objects in ArcObjects so maybe an interface does exist? If not, are you saying the geometry you are snapping to has a Z value? If so, this is one way to do it:

Cast your geometry into IPointCollection, cycle over this until you have the vertex you snapped to then query that vertex for a Z value.

The method I am suggesting assumes you are snapping to vertices.

Re: Is there any way to get the Z-Coordinate when snapping?

JeffMatson — Fri, 10 Dec 2021 21:26:22 GMT

I think if you make the point ZAware it should pick up the Z values automatically

Dim zAware As IZAware
Set zAware = pPoint
zAware.zAware = True

Hi Everybody:

I am writing some code to do snapping. When I snap a new point (with X and Y only) to an existing point feature (with XYZ coordinates). I will get the XY of the feature that it is snapped to, but not Z. Following is my current code. Is there anyway to identify the Z coordinate of the feature? For example, find the feature that is snapped to first, and then get Z?

Thank you!
// X, Y are the mouse coordinates, get the point on the map with Lat-Long but without Z coordinate
IPoint mapPoint;
mapPoint = QueryMapPoint((m_application.Document as IMxDocument).ActivatedView.ScreenDisplay, X, Y);

// snap
ISnappingResult snapResult = m_Snapper.FullSnap(mapPoint);
if (snapResult != null)
{
    IPoint SnappedMousePoint = snapResult.Location;   // only get the XY, but Z=NaN
}

Re: Is there any way to get the Z-Coordinate when snapping?

Anonymous User — Wed, 18 Sep 2013 16:52:40 GMT

Z snapping is only supported through the classic snapping environment. You can enable classic snapping on the UI through the editor options dialog or through the IEditProperties4.ClassicSnapping Property.

The help topic Working with the editor snap environment has a section on how to snap in x,y,z. Basically you enable zsnapping on feature snap agents, set the z snapping environment (ISnapEnvironment3) then snap a ZAware point with ISnapEnvironment.SnapPoint. We are working to make this easier in the future.

This pattern is used in the old 9.3 sample Z management properties. The sample has been rewritten for 10.1 as Z Management Toolbar.