Hi Torsten Torsten Eckart wrote: > Hallo, > could anyone give me a hint how to construct in grass on the > best way? I want to draw dams in an drainage stream system , they > have to have especial withs and heights. How to construct the streams > the best way?Than I want to calculate the amount of material what is to > move there to build the dams from natural material of that area. > Possible to export as .dxf and work in qcad? > Could someone gives me some links in the net?
You can calculate the dam wall volume, water volume and water surface area using raster map algebra. GRASS has various interpolation methods to create a surface from vector points. You would create three DEMs to represent the original ground surface, the dam wall surface and the water surface. Subtract the ground map from the wall map, set all negative values to zero, then sum all values in the resulting map and multiply by the cell area to get the volume of the wall. You could then create a polygon from this difference map, representing the wall's footprint and export it as dxf for further work in CAD. Craig _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
