Monday, July 18, 2016

Them there pesky contours...

You have a site plan, onto which you have put spot levels obtained from a field trip to the farm.

The need now, is to convert these to contours.  To do this accurately, you have to calculate the distance between two spot levels and then calculate from them, and the level information.

Which is a lot of calculation and fiddling around.

So, another lost weekend later I have a lisp routine that does this.  No doubt someone has already done something similar, but at least I can say I did it my way!

In the pic below you can see the spot levels in grey, and the contour text in red-in NZ we do them every half a metre.

Of course, you have to draw in the contour lines in afterwards, but the points are accurate, not guesses.

The next routine that flows from is where you pick two spot points, and then a third point, and the elevation of that third point is marked with an X and it's elevation put on the defpoints layer.

You can see the demo at