Roughness Map

[hyun_yoon]

I have a .shp map of roughness length. Each polygon in the map have its respective value of roughness length.
Importing this map in MapEditor, I found that the MapEditor could not read the roughness value. The GlobalMapper could not do the map transformation either.
I wonder how could I convert the polygon shapefile to the .map file used in WAsP Program. Thank you.

[T.Klaas]

Have you found an answer to your question? I have a similar problem. I have dxf files that contain information of the land usage. In order to that I want to create a roughness map for wasp by adding information about roughness length to the polygons in the dxf files.
Thanks for your answer

[Ari Bronstein]

Hi guys,

You can do this through GlobalMapper. There is a WAsP MAP export option under export vector data. It will export any lines or areas you have active, meaning that you would want to make sure only your height contours and roughness area shapes are active on the screen when you export.

To make roughnesses work, you have to go into the attributes of each area you're interested in exporting and make sure they have the following properties: ROUGH_L and ROUGH_R. Set the roughness values accordingly (in meters). In general, I think left is the shape interior and right is exterior, but you should check this in Map Editor and adjust as needed.

One caveat though: don't attempt this with roughness areas that cross the boundaries of other roughness areas, because GlobalMapper does not change the roughness values at intersections (i.e., if your lake is 50% inside a forest and 50% inside farmland, you can choose an exterior roughness of either 0.5m or 0.03m, but either way you'll encounter errors).

Hope this helps!

[T.Klaas]

Thank you for your answer. This might help, but GlobalMaper is quiet expansive. :-(

I found another software (SAGA GIS), which has a function to export wasp maps. It works with height contours very well. If I set the roughness attributes as you say it might also work for roughness maps. Do you mean to set the roughnes attributes for every polygon? Or does that only work with lines?

Thank you!