How can I best create a terrain grid and generate contours near water bodies.

kp50kp50 Global Mapper UserPosts: 9
When I generate contours from my terrain grid near water I have contours running down into the water itself. The edge of water that is used in making the terrain grid should stop the contours at the edge. Any suggestions?

Best Answer

  • sphillipssphillips Posts: 69
    Answer ✓
    My apologies for the delay in replying to you as I have been away.

    If you know the elevation of the water line you can tell Global Mapper to exclude it when generating the contours. In the Contour Generation Options dialogue under 'Elevation Range, enter the water level in the first box and leave the other one as it is. No contours will be generated below the elevation value you enter in the first box.


  • sphillipssphillips Posts: 69
    Can you share a screenshot so we can better understand your problem? Are the areas of water polygons, lines or the Water Display found in Tools > Configure > Vertical Options?
  • kp50kp50 Global Mapper User Posts: 9
    Thank you sphillips for your response. Here is the screenshot. It shows contours that should be above the water line generating in the water.
  • kp50kp50 Global Mapper User Posts: 9
    Thanks sphillips, that takes care of most of the problem. However in some cases I have contours generated inside the water body that are full 2+ feet higher in elevation the water edge. The water edge was used in generating the Terrain Grid so the contours shouldn't be in the water at all. I can use the same surface data in other software and the contours stop above the water edge. 
  • sphillipssphillips Posts: 69
    You have other options you can try. One is to create an area feature (with island) and then use it to create a pad to modify your surface. Then your contours will not encroach the water areas.

    Alternatively you can use your area feature to create a surface for your water. Then place it above your terrain and group both the terrain and water surface. Apply the contours to that group. I experimented in the area you are working using 30m Aster and the principal works. I used the latter option below.

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