Line of intersection between 2 DTMs

You can use this function to find the line of contact where two DTMs intersect. The line follows the exact path of intersection between the two DTMs, where the DTM triangles intersect.

To run this function: Choose Surfaces > DTM file functions > Line of intersection between 2 DTMs, or...

In the Function Chooser, type INTERSECT DTMS, and press ENTER.

Note: The DTMs used in this function must be created on the same plane.

You can use the string file produced by this function for many purposes. For example:

to delineate exactly between cut and fill material for volumes
to find where a DTM of a fault plane intersects a surface
to find where a DTM of a pit design intersects the natural surface

Fields on the Intersect DTMs for line of contact form

Field	Description
Define first DTM
Location	The name and location of the first DTM.
[Refresh]	Loads the Object ID and Trisolation ID drop-down lists with the objects and trisolations of the DTM. In Surpac 6.6.1 and earlier versions, when you selected a DTM in the Location field, Surpac would load the DTM, validate it, and then load the Object ID and Trisolation ID drop-down lists. You could not interact with the form until the process was complete, which could be a long time for some large DTMs. Now, Surpac does not load the drop-down lists until you click the Refresh button, and validation does not occur until you click Apply in the form. Any validation errors are reported in the Message window.
Object ID	The object number of the first DTM. You can type the Object ID or select it from the drop-down list, if the list is loaded.
Trisolation ID	The trisolation number of the first DTM.
Define second DTM
Location	The name and location of the second DTM.
[Refresh]	Loads the Object ID and Trisolation ID drop-down lists with the objects and trisolations of the DTM.
Object ID	The object number of the second DTM. You can type the Object ID or select it from the drop-down list, if the list is loaded.
Trisolation ID	The trisolation number of the second DTM.
Define result file
Output layer	The name and location of the string file that will store the results of the intersection.
String Number	The string number that stores the contact line segments.

Output

The lines of contact between the DTMs are stored in the string file.

Troubleshooting

Message	Description
`No intersection found between the DTMs`	The DTMs selected do not intersect. You must choose DTMs with some area of intersection for this function.
`The selected DTMs were not created on the same plane.`	The DTMs used must be created on the same plane. Choose different DTMs and recreate the DTMs on the same plane, or transform the data in one of the DTMs to match the plane of the other.