Slider for similar transparent colors

Ice Age MarkIce Age Mark Global Mapper UserPosts: 324Trusted User
edited March 2011 in Suggestion Box
Hello there,

Any chance of having a slider or numeric input for the "Make very similar colors transparent as well" function, to adjust how similar the color is for it to be made transparent; sort of like the "Create area features from equal values" option does with colors?

My state Geologic Survey and the USGS has large numbers of geologic maps in PDF (uuuggh!) and raster image format, and it will be years (if ever) before they will be issued in a GIS format. I spend much time geo-locating these (no small challenge), and overlaying them on (mostly NAIP) imagery and DEM data so I can use GM's live GPS tracking on a laptop and find geologic features in the field. An increased ability to render background colors transparent on these kinds of maps would be a great help.

Thanks for considering this,



  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited March 2011

    There is an advanced way to set this up now. If you save a workspace file with the 'Make Similar Colors Transparent' option checked each IMPORT command will have a TRANSPARENT_COLOR_DIST parameter specifying how close each color band of a color has to be to the transparent color to be treated as transparent. The default is 16, but you can increase or decrease that to change how close a color has to be to be considered transparent, then reload the workspace to get the new setting.

    Let me know if I can be of further assistance.


    Global Mapper Support
  • Ice Age MarkIce Age Mark Global Mapper User Posts: 324Trusted User
    edited March 2011
    Thanks Mike, that's just what I needed to help with these kinds of maps.

    GM support is the best known to humanity.


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