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WorldWind project shut down, this site probably will be too.

Hello all,

With the recent announcement that the NASA World Wind project has been shut down (https://worldwind.arc.nasa.gov/news/...ension-notice/) there is really very little reason to continue running this forum, and as NASA staff were providing most of the moderation and responses it will likely fill up with spam shortly.

Unless something changes in the near future, I will be shutting down worldwindcentral.com as well as this forum, as it is no longer useful. Most of the data on WWC is referencing the legacy C# version of World Wind anyway.

Thanks,
Matt.
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What is the current Placemarker clipping best practice ?

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  • What is the current Placemarker clipping best practice ?

    What is the current best practice for clipping Placemarkers ?

    Placemarkers generally behave as expected, but there is some undesirable clipping.

    Here, in a tilted and rotated view, the magenta marker is clipped by terrain elevation in the foreground as desired:
    Click image for larger version  Name:	terrain-clip-marker.png Views:	1 Size:	358.6 KB ID:	158561



    But when not tilted, the markers can be clipped by the terrain elevation in an undesirable manner:
    Click image for larger version  Name:	terrain-clip-marker-bad.png Views:	1 Size:	160.9 KB ID:	158562



    Worse still, when viewing the globe from a great enough distance to see the horizon, markers are being clipped by the earth's surface:
    Click image for larger version  Name:	terrain-clip-marker-bad-2.png Views:	1 Size:	268.5 KB ID:	158563



    I have seen a few posts that discuss some workarounds and tracked issues regarding near/far clipping rotation and tilt, but I'm not sure what is the current best method to deal with this case scenario.

    Please can you offer some suggestions ?

    Thanks

  • #2
    Hi Timoto,
    Did you try to set an altitude to the Placemark ? Setting 5000m would avoid most mountains...
    If this is bad trick when zooming in, maybe also add a sort of vertical "tail" down to the ground... ?
    Perhaps not possible(s) with the web version...

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    • #3
      Hi frenchy

      Thanks again for your input.

      The suggestion would result in Placemarkers floating in mid air and a tail would look unattractive. I'm not sure it would solve the issue with the Placemarkers disappearing into the surface of the globe when viewed from a distance either.

      I presume there must be a mathematical method to resolving some aspects of this issue. Whilst there is no elevation data that I can see in google maps, their WebGL globe is 3D and their markers are not disappearing into the earth's surface,

      Click image for larger version

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      Click image for larger version

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      as they are doing with NWWW:
      Click image for larger version

Name:	terrain-clip-marker-bad-2.png
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ID:	158569

      Comment


      • #4
        There is no satisfactory solution provided here. But the desired effect can be achieved using Cesium js instead of NWWW.

        Screenshot of markers rendered in Cesium

        Click image for larger version

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        Attached Files
        Last edited by timoto; 09-17-2018, 04:00 AM.

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