Creating rougness vector with global mapper?

[mrswordf1sh]

i have a dxf map file which i will use to do wind analysis. In order to analyse and plot the mean wind speed in the area defined by me, i need to add roughness vector to the map. I have global mapper program but i couldn't do it with it. Anyone can help me how to do it with global mapper or is there any easy way to do it not manually?

[mrswordf1sh]

Other quesition is, Is there any way to obtain digital map from any area of the world with global mapper or other programs to use in WaSP. Since i am a mechanicel engineer, i have no idea about these map things. Thanks.