Global Mapper v25.0

Editing Elevation data

mapping
mapping Global Mapper User
edited September 2010 in Elevation Data
Hi,

I am new to GIS, I am wondering can GM perform the following actions, if possible, please kindly guide me along.

# I am using DTED file format, currently when I export the DTED file, it generated 12 files, is there a way to configure such that it can export to 1 DTED file?

# I need to modify the DTED information, i.e. I need to change the mountains to oceans. I am wondering how can I highlight the irregular shape and change the area to oceans.

Kindly please help.

Thanks a lot.

Comments

  • global_mapper
    global_mapper Administrator
    edited August 2010
    The DTED format specification only allows for DTED files to be generated along particular boundaries, so whatever bounding box and DTED level that you specify for export determines the files that are created. It is not possible to create DTED files along arbitrary boundaries.

    To change the elevation values of an area, you can create an area feature with the Digitizer Tool over the area of interest and provide an ELEVATION attribute with the new desired elevation, then select that area, right-click, then select the Advanced Feature Creation option to Create/Flatten Terrain from the area. This will create a new terrain surface from the area using it's elevation that will then combine with other terrain layers on export.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • mapping
    mapping Global Mapper User
    edited September 2010
    Thanks for the information...

    I have follow ur steps to change the elevation attribute, however, i am unable to convert the area to sea. i.e. I currently have 12x DTED file, I would like to convert an irregular portion of the DTED to sea (-300ft), however, after I follow the steps, I only manage to get a zero elevation terrain. How do I make this flat terrain to -300ft sea level. Currently i am using Globalmapper 10.

    Thanks.
  • global_mapper
    global_mapper Administrator
    edited September 2010
    What you can do is load your DTED data, create an area feature with your irregular shape with the Digitizer Tool and provide it with an ELEVATION attribute with a value of '-300 ft' (or you can add that attribute to an existing area if you have one already loaded). Then, select that area with the Digitizer Tool, then right-click and select the Advanced Feature Creation option to Create/Flatten terrain from the area. Once you have the new irregular terrain at a height of -300 ft on top of your DTED, then do your export. The topmost values should be used at each location, so you should get new files with -300 ft as the elevation within your irregular areas.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com