cesium-geoserverterrainprovider

v0.8.0

Published

5 months ago

plugin to create a Cesium terrain provider from Geoserver

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egemenozgur

Cesium Geoserver Geoserver

cesium-GeoserverTerrainProvider

GeoserverTerrainProvider: A terrain provider which works with geoserver providing elevation datas in bil, png, gif and jpeg formats. The png format should be prefered.

Cesium version

Tested with Cesium 1.95 and geoserver 2.21.

License: Apache 2.0. Free for commercial and non-commercial use. See LICENSE.md.

Usage

Optional: import mySLD.xml as a new style in geoserver to render your layer (16 bits grayscale) in other color range.
Import the GeoserverTerrainProvider.js file into your html codes after importing Cesium.js.
Create a new instance of GeoserverTerrainProvider with url of your geoserver and name of elevation layer.

After that, the GeoserverTerrainProvider will determine the capabilities of geoserver (request getCapabilities) and will be ready to provide terrain data.

Example

    <script src="/path/to/Cesium.js" type="text/javascript"></script>
    <script src="/path/to/GeoserverTerrainProvider.js" type="text/javascript"></script>
    <body>
    <div id="cesiumContainer"></div>
    <script>
      async function init(){
        const container = document.getElementById('cesiumContainer');
        const terrainProvider = await Cesium.GeoserverTerrainProvider({
              "url": "http://localhost:8080/geoserver",
              "layerName": "elevation:SRTM90"
        });
        const imageryProvider = new Cesium.WebMapServiceImageryProvider({
          "url": "http://localhost:8080/geoserver/ows",
          "parameters": {
                  "format": "image/png",
                  "transparent": true
                },
          "layers": "raster:naturalEarthPyramid",
          "maximumLevel": 15
        });

        const options = {
          imageryProvider: imageryProvider,
          baseLayerPicker: false,
          showRenderLoopErrors: true,
          animation: true,
          fullscreenButton: false,
          geocoder: false,
          homeButton: false,
          infoBox: false,
          sceneModePicker: true,
          selectionIndicator: false,
          timeline: false,
          navigationHelpButton: false,
          navigationInstructionsInitiallyVisible: false,
          targetFrameRate: 30,
          terrainExaggeration: 1.0,
        };

        viewer = new Cesium.Viewer(container, options);
        viewer.terrainProvider = terrainProvider;
      }
      init();
    </script>
  </body>

Where

Display created with bing map imagery provider and geoserverTerrainProvider. This last was configured with SRTM map of 90 meters resolution.

More precisions on styleName parameter

You'll find "styleName" parameter after inserting mySLD.xml as a new style usable for the elevation layer (here it's grayToColor)

The "styleName" parameter is useful when bil plugin can't provide good data. Nevertheless it takes lots of time to geoserver to generate a new image with style. Beforehand, thank to GeoWebCache you can generate the styled images (very long process).

Which format?

GeoserverTerrainProvider can work with BIL/DDS (use of BIL/DDS plugin in geoserver), styled Images (use of mySLD.xml) and converted Images (see here). The images have to be process by internet navigator also the image formats are gif, jpeg and png.

Original geotiff

It's a 16 bit grayscale geotiff used by BIL/DDS plugin to generate an arrayData.

Styled geotiff

It's a 8 bits red green blue geotiff format that geoserver serves as an image where most significant byte from 16 bit grayscale is stored in color red and least significant byte from 16 bit grayscale is stored in color green. Moreover there is an offset of 32768 meters in order to have only positive numbers.

Converted geotiff BREAKING CHANGE

In nutshell

Which service ?

GeoserverTerrainProvider can use:

Web Map Service provided by geoserver or geoWebCache (version 1.1.1 and version 1.3.0) more details here
Tile Map Service provided by geoWebCache (version 1.0) here
Web Map Tile Service provided by geoWebCache (version 1.0) here

Little helps to use SRTM (elevation maps) in geoserver

you can download SRTM data at http://srtm.csi.cgiar.org/ or http://www.viewfinderpanoramas.org/ (90 meters or 3 seconds arc resolution of map is better)
install GDAL tools and python to work with SRTM http://trac.osgeo.org/gdal/wiki/DownloadingGdalBinaries
install geoserver image pyramid plugin
generate a pyramid from SRTM data with gdal_retile command from GDAL tools
create a layer from generated pyramid ( a guide is available here)