Reshaping DTM Contours with the 2D Reshape Tool

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A common complaint about the DTM is that there is no way to reshape the contours using the 2D Reshape tool. Actually, there IS a way to do this, though you cannot edit the DTM directly. Since the DTM can only be altered by Site Modifiers, you have to create Site Modifiers first. Then you can edit the Site Modifiers with the 2D Reshape tool.

Consider this sample DTM, and suppose that I want to smooth out some of the contours in the center of the area shown, to create a gradual slope.

So I select the Site Modifiers tool, and draw an open poly where I want one of the contours to be.

Then, in the Object Info palette, I set the Config parameter to "Pad," and the Elevation parameter to the elevation of the contour in question.

I then repeat this for each of the contours that I want to re-define.

Then I create another Site Modifier to be a fence around the whole thing. This will control the scope of the change that I want to make, and without a fence, the DTM will not know what to do with the "pads" that I have just created.

When I update the DTM -- shazam -- the proposed contours now follow my "pads."

Having done this, I don't like how my new contours fare back into the existing, so I add a few more "pads," stretch the fence to still enclose all of them, and then update the DTM.

Now I've got (more or less) exactly what I want. And if I want to alter one of these contours, I simply double-click the Site Modifier object, and the 2D Reshape tool is activated, so I can drag around the vertexes to my liking.

Charles 20:00, 4 May 2008 (EDT)

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