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Thread: Poland super-overlay discussion

  1. #1
    Senior Member Tom Baldwin's Avatar
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    Default Poland super-overlay discussion

    This is a discussion thread for the following file:

    Poland super-overlay

    Poland super-overlay, with data from source: Zumi.pl

    Much better coverage that have Google Earth.



    File hotlink: http://www.virtualexile.com/GEocentric/zumi/


  2. #2
    Senior Member Tom Baldwin's Avatar
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    This is a splendid piece of work. A real eye-opener for GE!

    The coverage is not 100%, as I discovered when, after finding the first two inclined planes on the Elblag canal, I hit a lowres block. See my placemark but make sure the Poland super layer is on. Also, the performance is not spectacular; probably a function of the Polish server's capability to deliver the mapping.

    Nevertheless, this is a major step forward for Poland in GE. Well done!
    Attached Files Attached Files

  3. #3
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    Yes, performance of other my multilevel overlays is also low at closer zoom.
    See:

    Poland - map
    http://www.virtualexile.com/GEocentric/zumi-mapa/

    Poland - hybrid (Google satellite images + Zumi.pl map)
    http://www.virtualexile.com/GEocentric/zumi-hybryda/

    Microsoft Virtual Earth (no polish servers
    http://www.virtualexile.com/GEocentric/virtualearth/

    Polish servers are very fast.
    I think, that 3d engine of Google Earth and our graphics cards are no ready jet for displaying so high amount of multilevel texture data at country level or world-wide overlays... or i do something wrong in my kml files

  4. #4

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    Quote Originally Posted by GEocentric View Post
    Yes, performance of other my multilevel overlays is also low at closer zoom.
    See:

    I think, that 3d engine of Google Earth and our graphics cards are no ready jet for displaying so high amount of multilevel texture data at country level or world-wide overlays... or i do something wrong in my kml files
    SuperOverlays are very picky. If they are not set up correctly, performance will not be so good. I can see several possible problems with your Poland SuperOverlay

    1) You have too many levels of tiles (12 levels??). Each level is always loaded on top of each other, so that is a lot of extra tiles. Better to use bigger tiles (1024x1024 max) and fewer levels (5 or 6 levels is best). You might also have to split up so that all the KML code does not have to load at startup. See www.gelib.com/maps/Sectionals/Sectionals.kml for example. This is 60 separate SuperOverlays, so each one only loads when you zoom to that area.

    minLodPixels may be set too low. Higher this number, the lower the bandwidth requirements. You have it set to 128. If you set to 256 will require 1/4 the bandwidth and probably little or no difference in visual quality.

    KML format - You are using the old SuperOverlay format where there is 1 KML file for every tile. Performance much better if you use the new SuperOverlay format where there is just 1 KML file for ALL of the tiles. Much less file transfer overhead.

    Good luck.

    Matt
    Matt Fox

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