I need to subtract 2.4m from the z value(elevation) of 1,700,007 points, and then

I need to subtract 2.4m from the z value(elevation) of 1,700,007 points, and then shift all these points about a point to another point at a bearing of 276° 27' , 1.273m , surely this can be done, just can't find it!

Thanks in advance

Answers

  • GillanoGillano Posts: 4
    Export the points to a .CSV file and manipulate them in Excel (i.e. once you have the x, y and z in different columns you can easily add 2.4m to the elevation; also the x and y can be modified in the same way).
    when you've done re-import the .CSV file in Global Mapper and it's done!
  • MykleMykle Global Mapper User Posts: 381Trusted User
    The spreadsheet method works.  If you have more work to do with the attributes of these points, this may be the preferred option. 

    Otherwise the steps you describe can be completed in Global Mapper to shift by bearing and distance, then by elevation.

    Shift by bearing and distance (sounds like each point needs to shift the same distance and in the same direction):
    - select your points
    - right-click, select "Move/Reshape Feature(s)", and select "SHIFT - Shift (Offset) Selected Feature(s)"
    - select "Specify Offset as Distance and Bearing" and enter your values: 276 27 and 1.273
    (enter the bearing as 276 space 27, otherwise convert to decimal degrees)
    (ensure that you value is a bearing that is relative to true north, increasing clockwise, meaning your shift is west and slightly north.  Otherwise convert from whatever you are using)

    Shift by elevation:
    - select your points
    - right-click, select "Attribute / Style Functions", and select "Calculate/Copy Attributes for Feature Selection"
    - select "Use Simple Calculation"
    - set "Source Attribute" to "ELEVATION" (or whatever attribute contains your elevation value)
    - set "Operation" to "Add"
    - select "Use Fixed Value" and enter your value (-2.4)
    - click on the "Calculate" button at the bottom of the dialog.


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