Update Intersecting DTMs

To access this dialog:

Structure ribbon | Operations | DTMs | Update Intersecting DTM
Run the command wireframe-surface-merge-intersecting.

Surface operation to update one wireframe DTM surface with another.

This command differs from wireframe-surface-merge (Update DTM) in that it assumes a clean intersection of both DTM surfaces exists. If you are confident that both surfaces intersect cleanly/fully, this command will be able to offer a performance improvement over wireframe-surface-merge for the same data inputs.

Note: This command supports flexible wireframe selection.

Field Details:

DTM 1: select the first wireframe object, either using the drop-down list, or choose triangle data from one or more wireframe objects interactively, then commit the selection to the command using Store current selection. The selected data will be merged with the second object.

DTM 2: as above, but this time confirm the data to be used as the second DTM.

Excavate DTM 1 with DTM 2: the elevation of object 1 will be set the minimum of its current elevation, or the elevation of object 2.

Elevate DTM 1 with DTM 2: the elevation of object 1 will be set to the maximum of its current elevation, or the elevation of object 2.

For both Excavate and Elevate options, if a jump between elevations on an open edge of object 2 would cause a break in the resultant surface, this gap is filled with vertical triangles.

The two options listed above are exclusive.

Example:

In the following example, a surface topography and pit DTM are loaded into memory. Object 1, in this case, is the pit and Object 2 is represented by the topography:

Options

What Happens

Result

Excavate Option Selected

Elevate Option Disabled

The elevation of the pit DTM is set the minimum elevation represented by both objects. In effect, the points of the pit wireframe are 'dropped' onto the nearest available surface, resulting in an object that matches the boundaries of the pit, but the minimum possible elevations.

Note in the example how a mixture of both pit and topography values are used to represent the merged object, hence both attributes are shown.

Excavate Option Disabled

Elevate Option Selected

As above, but maximum values for elevation are used when both objects are taken into account.

Again, note how points for the new merged object are derived from both original DTMs, so both attributes are represented.

Output: you can output data either within the Current object, an existing wireframe object (pick it from the list) or a new object (type a new name).

	Related Topics
	Wireframe Merge DTMs Dialog wireframe-surface-merge-intersecting wireframe-surface-merge