node-hgt
Read and query HGT files, for example from SRTM, for elevation data with high performance.
Optionally, this module can also use cached and automatically download HGT files as required.
node-hgt tries to be reasonably performant. A rough benchmark shows it can do 1.8M elevation calculations
per second on my years old laptop.
Install
npm install --save node-hgt
Usage
Load and query a HGT file:
var hgt = new Hgt(__dirname + '/data/N57E011.hgt', [57, 11]);
hgt.getElevation([57, 11])
Use a cache directory of HGT files for querying. Missing data will be downloaded
using the elevation data index from imagico.de,
by default.
var tileset = new TileSet('./data/');
tileset.getElevation([57.7, 11.9], function(err, elevation) {
if (err) {
console.log('getElevation failed: ' + err.message);
} else {
console.log(elevation);
}
});
There's also a synchronous tile set, if you know before hand which area you will query:
var tileset = new SyncTileSet('./data/', [57, 11], [58, 12], function(err) {
if (err) {
console.log(err);
return;
}
var elevation = tileset.getElevation([57.7, 11.9]);
console.log(elevation);
}
});
});