Global Mapper v25.0

How to edit ASCII elevation data

Hi,

I have 0.5m grid elevation in ASCII format data. Is there any option to edit the very few pixel elevation in global mapper.
It would be great if i got any suggestion regarding this.

Regards,
Sundarrajan

Answers

  • Thea_bmg
    Thea_bmg Global Mapper User
    There are several ways to edit terrain data in Global Mapper in the 'Alter Elevation Data' tab of the layer options.  For example, you can set the elevation range of valid data, and replace all values outside of this range with a different value.  You can also add or subtract values, so you could slightly raise or lower your values using the 'Elevation Offset' option.
  • Thanks. It will help to adjust the elevation of whole data. But my requirement is edit the elevation data within the portion of the vector like bridge,few voids fill with values.Is there any option to do this?
  • bmg_bob
    bmg_bob Global Mapper Programmer
    You can use the Raster Calculator for this:

    1) Select the area feature(s). (Note that all of the pixels under the feature will be set to the same elevation value in this process.)
    2) Choose the Analysis->Raster Calculator menu item.  The Set up Apply Formula Operation window will open.
    3) Put a dot next to Add Custom Formula, and type the elevation you want.
    3) Click Add Band.  Your formula will go into the list.
    4) Note the Bit Depth and Grid Unit options under Set up Output Grid Settings.  Make sure those are set correctly.
    5) Click the Export Bounds tab.
    6) Choose the Crop to Selected Area Feature(s) option.
    7) Click OK.  A new elevation grid layer will be added to your map with the elevation that you specified.  The data values will only be within the bounds of the features you selected.
    8) To get an updated grid file, export all of the data to the elevation grid format of your choice.