Contour Extrapolation

[RobinLee1]

Hi guys,

A bit stuck on some work of mine and was wondering if anyone had a solution. Basically I want to perform a step by step extrapolation of elevation contours from a hill down to the subsurface, particularly preserving the valleys and general shape. I've attached a picture which can hopefully help illustrate what I mean. The purple line is at 25m elevation, blue line is 50m and green line is 75m. Basically I want to use these contours to predict where the 0m, -25m, -50m etc. contours would be. The only form of "programming" I can use is Matlab so I may be somewhat limited in processing outside of ArcGIS. Any help would be much appreciated!

[ShaunWalbridge]

Do you have the input raster data which the contours are derived from? If you do have them, you can create new contours at the desired intervals directly, and not have to do any 'tricks' to guess where they might be. If you don't have them, you could probably make a function which measured the distances between the 25/50/75m lines and made a guess at where the next intervals would lie, but it'd be just a simple picture and not based on the geomorphology of the landscape.

cheers,
Shaun

[SteveLynch]

Have a look at TopoToRaster in the Spatial Analyst toolbox