Global Mapper v25.0

watershed analysis

skk
skk Global Mapper User
Is there an option to generate analysis similar to watershed; all around a defined point  but based on an inclined surface, say 1 degree; need to analyse if inside a valley, can you clear the valley.

Answers

  • JSL
    JSL Global Mapper User Trusted User
    Are you trying to determine the low point of the valley?
  • coelodonta
    coelodonta Global Mapper User
    In not sure what you're trying to do here but i often just create a square area feature and edit the vertices to get my slope  angle then cut or calculate one surface against another using the combine compare terrain tool
  • skk
    skk Global Mapper User
    Thanks for your reply. This is to see how a climbing aircraft will clear high surrounding terrain. Watershed analysis finds intersection of a given plane with the terrain. This one would need intersection of terrain with an inverted cone where semi-apex angle of the cone corresponds to the climb gradient (=90-climb angle). 
  • JSL
    JSL Global Mapper User Trusted User
    I don't know how to do it, but if you could figure out how to make a 3-D model of the cone, maybe you could use the Combine/Compare Terrain Layers or the Create Flattened Site plan functions to see if there are any intersections between the cone and the terrain.