Global Mapper Pro

Combine high and low resolution grids

naugustin Global Mapper UserTrusted User
edited September 2014 in Elevation Data
I try to combine some AUV grids (1m, 50cm resolution) and a ship bathymetric grid (10m resolution). Using the fading option to fade the edges of the grids and avoid sharp rims where the resolution change looks good in GM. However, I don´t make my maps in GM and want to export the combined grids to work in other programs but the results always don´t resample the fading good enough (see screen grabs).

That´s how it looks in GM (10m, 1m, 50cm with edge fading of 150 pixels):

That´s how it looks after export (*.asc, 50cm, resampling: automatically).
The line in the picture is the rim of the polygon I used for the fading:

How can I improve this? Is there any idea or any setting I could try?

Best, Nico


  • DMcKittrick
    DMcKittrick Global Mapper Trainer Trusted User
    edited September 2014
    Have you tried feathering the adjacent/overlapping elevation layers without defining the feather area with a polygon? How about extending the pixel border size? When exporting, try the No Resampling option.

    Failing this, try exporting to a Global Mapper Grid (.gmg) and re-import that file. Then try exporting the reloaded data in .asc format.

    - David McKittrick
    Senior Applications Specialist
    Blue Marble Geographics
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