Cesium Terrain Provider
sampleterrain - Update coordinates of a GeoJSON file from node.js with sampled elevation data from aWhen you work with Cesium, often times you need to incorporate elevation data in your geo features so that they are properly positioned relative to the ground when using terrain visualization. You can do it in the browser by invoking the Cesium.sampleTerrain function, but if your features have tons of coordinates, it will be very slow. Many times it will be much better to preprocess the data off-line to include elevation information.
This small library allows you to do that from a node.js application.
Performance note: For large files, it is better to explicitly specify level of detail as the default 'sampleTerrainMostDetailed' can be very slow.
NOTE: Currently Cesium has an issue running in Node.js applications. The dependencies have been temporarily updated to point to Cesium branch in jimmyangel/cesium repo. See Cesium issue 8559
Install
npm install sampleterrain
Use as library
var sampleterrain = require('sampleterrain');
sampleterrain.sample(data, fOptions).then((result) => {
console.log(JSON.stringify(result));
}).catch(e => {
console.warn('Sample terrain error', e);
});
Where:
data - GeoJSON object
fOptions - {level: level, terrainProviderUrl: url}
level - The terrain level-of-detail from which to sample terrain heights (defaults to maximum detail)
url - The url of the terrain provider (default to the Cesium Ion world terrain provider)
result - Updated GeoJSON object
Use from the command line
Usage:
sampleterrain.js [OPTIONS] [ARGS]
Options:
-f, --file FILE GeoJson File
-l, --level NUMBER Terrain level of detail
-u, --url URL Terrain provider url
-h, --help Display help and usage details
Example
node sampleterrain.js -f ./sampledata/test1.json > sampled.json