Global Mapper v25.0

"Gap" detection

STH
STH Global Mapper UserTrusted User
edited July 2009 in Suggestion Box
Is it possible to implement a small "gap detection" algorithm. This should run before the export starts for instance of a large ECW-consisting of many files. You can have the habit to always turn on "Fill small gaps" - however this takes alot more time and not using it is the best option. What I usually do when I encounter small gaps between files I update the TFW-file accompanying (by 1/2 or 1 pixels) to fill the gap and then export it.

Comments

  • global_mapper
    global_mapper Administrator
    edited July 2009
    I'm afraid that a "small gap" detection tool would take just as long as the export with small gap fixing enabled as it would basically have to evaluate each pixel in the export for small gaps as gaps can be interior to images as well as at edges with transparency, so just checking bounding boxes is not sufficient.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • STH
    STH Global Mapper User Trusted User
    edited July 2009
    Perhaps I used the term "gap" in the wrong way. What I wanted to check was just the "bounding box" of each "file" compared to the "bounding box" of the neighbouring file - to detect if for instance one file is shifted 0.5 pixels to the north/south/east/west for the neighbouring file. This is to eliminate the 1pixel-gap between the borders of files that might have the wrong coordinate. Not sure if I express myself correctly...
  • global_mapper
    global_mapper Administrator
    edited July 2009
    Something like this could maybe be added, but would only work in a simple manner on the limited case of files with the same native projection and who don't have any collars that have been removed or transparent edges of any kind.

    In general the 'Fill Small Gaps' menu command will only slow down an export that actually has gaps or void areas somewhere. If your export fills the entire export bounds there should be no difference. If you just have some small gaps only those pixels will be slightly slower, so you probably wouldn't even notice in that case.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com