ModifyVertex

Alters the position of a specified vertex of the polyline.

HRESULT ModifyVertex(

[in] int Index,

[in] double X,

[in] double Height,

[in] double Y,

[in, defaultvalue(0)] long Flags)

Parameters:

Index – Indicates which vertex you intend to modify, within the polyline (this must be a value between 0 and NumOfVertices-1).
X – The West-East coordinate of the vertex. You can use the ITerrain interface to retrieve information about the MPT units. If you are working in Lat-Long format, the Lat-Long values are in decimal Lat-Long.
Height – The height of the vertex in meters.
Y – The North-South coordinate of the vertex. You can use the ITerrain interface to retrieve information about the MPT units. If you are working in Lat-Long format, the Lat-Long values are in decimal Lat-Long.
Flags – Determine precisely how the new vertex is positioned. It can, for example, be positioned relative to the previous vertex. Below are the valid flags (from which you can form different combinations) for this method.

NEW_ELEVATION_RELATIVE_TO_CURRENT_ELEVATION = 64
The height of this vertex is the value of the Height parameter plus the height of the previous vertex.
Note: This flag must never be used for the first vertex of the polyline.
NEW_POS_RELATIVE_TO_CURRENT_POS = 128
The coordinates of this vertex are determined by adding the values of the coordinates of the previous vertex to the values of the X and Y parameters.
DONT_REDRAW = 512
When modifying several vertices in a row, it is more efficient (performance-wise) to redraw the polyline only after the last vertex has been modified. In this case, all of the ModifyVertex() calls except for the last, should have this flag set.

Return Values:

The return value obtained from the returned HRESULT can be one of the following:

Return value	Meaning
S_OK	Success.
E_FAIL	Catastrophic failure.
TE_E_TEOBJECT_NOLONGEREXIST	The object you are trying to access no longer exists. This may have occurred because, while keeping an interface to the object, the user deleted it from TerraExplorer (via the TE user interface). Without the object, the interface cannot be used. Therefore, you should release the interface.
TE_E_INTERNAL	TerraExplorer was unable to create the object. To get more information about this error use the IErrorInfo Interface.