This command allows you to create elevation mappings from contour lines in VSP. These elevation mappings can be used as the tops of piles or the bottoms of lakes / ponds in 3D sampling.
To complete this process you must have two or more contour lines in VSP at different elevations (Z-Offsets). One of the contour lines must outline the sample area that will be mapped:
In this case, notice that its Z Offset is 0. It doesn't have to be 0, it just has to have a Z Offset that is different from the other contours. A second contour (which is a closed polyline) must be contained completely inside the sample area and have a different Z Offset:
In this case the contained contour has a Z Offset of 10. More contours may be included as long as they follow these rules:
Must be closed
Must not cross another polyline
Must be completely inside the sample area
After the contours are properly set up, this command will now ask for the type of contour interpolation:
Linear interpolation makes straight-line interpolation between the contour elevations. For this example, linear interpolation would look like:
Cubic spline interpolation fits smooth curves between the contour elevations. For this example, cubic spline interpolation would look like:
The "Keep inner contours flat" option is available for the cubic spline interpolation and flattens the area inside of the inner-most contours.
If inner contours are lower than the contour of the sample area, it will create a depression that would be typical of a lake or pond. Note that any sample areas will be removed if they are inside the sample area being mapped.
Once the elevation mappings are created they are stored with the project file. They can also be exported to a file and imported into another project. They can also be deleted from the project. But the most important use for the elevation mappings is for Z Placement on the sample placement page.