84 lines
1.8 KiB
Markdown
84 lines
1.8 KiB
Markdown
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gps-distance
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============
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[](https://nodei.co/npm/gps-distance/)
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A node module for performing distance calculations between GPS coordinates
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Installation
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------------
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```
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npm install gps-distance
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```
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Examples
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========
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`gps-distance` supports two syntaxes for convenience. You can measure just between two points and supply in your GPS coordinates as direct arguments to distance in the form `(source_lat, source_lon, destination_lat, destination_lon)`, or you can use an array of points each in `[lat,lon]` format. See the examples below.
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Point to Point
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--------------
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```javascript
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var distance = require('gps-distance');
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// Measure between two points:
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var result = distance(45.527517, -122.718766, 45.373373, -121.693604);
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// result is 81.78450202539503
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```
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Array of GPS points
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-------------------
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```javascript
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// Measure a list of GPS points along a path:
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var path = [
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[45.527517, -122.718766],
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[45.373373, -121.693604],
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[45.527517, -122.718766]
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];
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var result2 = distance(path);
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// result2 is 163.56900405079006
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```
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Measuring Distance From a .GPX File
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-----------------------------------
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To compute the distance travelled in a tracked GPX file, use `gps-distance` with the `gpx-stream` module ( http://npmjs.org/package/gpx-stream/ ).
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```javascript
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var GPXstream = require('gpx-stream');
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var distance = require('gps-distance');
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var points = new GPXstream();
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var source = fs.createReadStream('./marathon.gpx');
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var path = [];
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source.pipe(points);
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points.on('readable', function() {
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var point;
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while(point = points.read()) {
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path.push([point.lat, point.lon]);
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}
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});
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points.on('end', function() {
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console.log('Distance travelled: ' + distance(path) + ' km');
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});
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```
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Notes
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-----
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Distances are returned in kilometers and computed using the Haversine formula.
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