238 lines
6.6 KiB
Markdown
238 lines
6.6 KiB
Markdown
# Geolib
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[](http://travis-ci.org/manuelbieh/Geolib)
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A small library to provide some basic geo functions like distance calculation, conversion of decimal coordinates to sexagesimal and vice versa, etc.
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[View demo](http://www.manuel-bieh.de/publikationen/scripts/geolib/demo.html)
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<h2>Methods</h2>
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<h3>geolib.getDistance(object start, object end[, int accuracy])</h3>
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Calculates the distance between two geo coordinates
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Takes 2 or 3. First 2 arguments must be an object with a latitude and a longitude property (e.g. {latitude: 52.518611, longitude: 13.408056}). Coordinates can be in sexagesimal or decimal format. 3rd argument is accuracy (in meters). So a calculated distance of 1248 meters with an accuracy of 100 is returned as 1200.
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Return value is always an integer and represents the distance in meters.
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<h4>Examples</h4>
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<pre>geolib.getDistance(
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{latitude: 51.5103, longitude: 7.49347},
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{latitude: "51° 31' N", longitude: "7° 28' E"}
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);
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geolib.getDistance(
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{latitude: 51.5103, longitude: 7.49347},
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{latitude: "51° 31' N", longitude: "7° 28' E"}
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);
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// Working with W3C Geolocation API
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navigator.geolocation.getCurrentPosition(
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function(position) {
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alert('You are ' + geolib.getDistance(position.coords, {
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latitude: 51.525,
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longitude: 7.4575
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}) + ' meters away from 51.525, 7.4575');
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},
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function() {
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alert('Position could not be determined.')
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},
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{
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enableHighAccuracy: true
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}
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);
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</pre>
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<h3>geolib.getCenter(array coords)</h3>
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Calculates the geographical center of all points in a collection of geo coordinates
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Takes an object or array of coordinates and calculates the center of it.
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Returns an object: `{"latitude": centerLat, "longitude": centerLng, "distance": diagonalDistance}`
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<h4>Examples</h4>
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<pre>var spots = {
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"Brandenburg Gate, Berlin": {latitude: 52.516272, longitude: 13.377722},
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"Dortmund U-Tower": {latitude: 51.515, longitude: 7.453619},
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"London Eye": {latitude: 51.503333, longitude: -0.119722},
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"Kremlin, Moscow": {latitude: 55.751667, longitude: 37.617778},
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"Eiffel Tower, Paris": {latitude: 48.8583, longitude: 2.2945},
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"Riksdag building, Stockholm": {latitude: 59.3275, longitude: 18.0675},
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"Royal Palace, Oslo": {latitude: 59.916911, longitude: 10.727567}
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}
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geolib.getCenter(spots);
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geolib.getCenter([
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{latitude: 52.516272, longitude: 13.377722},
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{latitude: 51.515, longitude: 7.453619},
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{latitude: 51.503333, longitude: -0.119722}
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]);
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</pre>
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<h3>geolib.isPointInside(object latlng, array coords)</h3>
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Checks whether a point is inside of a polygon or not.
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Note: the polygon coords must be in correct order!
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Returns true or false
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<h4>Example</h4>
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<pre>
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geolib.isPointInside(
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{latitude: 51.5125, longitude: 7.485},
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[
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{latitude: 51.50, longitude: 7.40},
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{latitude: 51.555, longitude: 7.40},
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{latitude: 51.555, longitude: 7.625},
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{latitude: 51.5125, longitude: 7.625}
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]
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); // -> true</pre>
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<h3>geolib.isPointInCircle(object latlng, object center, integer radius)</h3>
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Similar to is point inside: checks whether a point is inside of a circle or not.
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Returns true or false
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<h4>Example</h4>
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<pre>// checks if 51.525, 7.4575 is within a radius of 5km from 51.5175, 7.4678
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geolib.isPointInCircle(
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{latitude: 51.525, longitude: 7.4575},
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{latitude: 51.5175, longitude: 7.4678},
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5000
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);</pre>
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<h3>geolib.orderByDistance(object latlng, mixed coords)</h3>
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Sorts an object or array of coords by distance from a reference coordinate
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Returns a sorted array [{latitude: x, longitude: y, distance: z, key: property}]
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<h4>Examples</h4>
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<pre>
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// coords array
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geolib.orderByDistance({latitude: 51.515, longitude: 7.453619}, [
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{latitude: 52.516272, longitude: 13.377722},
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{latitude: 51.518, longitude: 7.45425},
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{latitude: 51.503333, longitude: -0.119722}
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]);
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// coords object
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geolib.orderByDistance({latitude: 51.515, longitude: 7.453619}, {
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a: {latitude: 52.516272, longitude: 13.377722},
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b: {latitude: 51.518, longitude: 7.45425},
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c: {latitude: 51.503333, longitude: -0.119722}
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});
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</pre>
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<h3>geolib.findNearest(object latlng, mixed coords[, int offset])</h3>
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Finds the nearest coordinate to a reference coordinate.
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<h4>Examples</h4>
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<pre>var spots = {
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"Brandenburg Gate, Berlin": {latitude: 52.516272, longitude: 13.377722},
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"Dortmund U-Tower": {latitude: 51.515, longitude: 7.453619},
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"London Eye": {latitude: 51.503333, longitude: -0.119722},
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"Kremlin, Moscow": {latitude: 55.751667, longitude: 37.617778},
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"Eiffel Tower, Paris": {latitude: 48.8583, longitude: 2.2945},
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"Riksdag building, Stockholm": {latitude: 59.3275, longitude: 18.0675},
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"Royal Palace, Oslo": {latitude: 59.916911, longitude: 10.727567}
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}
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// in this case set offset to 1 otherwise the nearest point will always be your reference point
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geolib.findNearest(spots['Dortmund U-Tower'], spots, 1)
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</pre>
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<h3>geolib.getPathLength(mixed coords)</h3>
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Calculates the length of a collection of coordinates
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Returns the length of the path in kilometers
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<h4>Example</h4>
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<pre>
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// Calculate distance from Berlin via Dortmund to London
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geolib.getPathLength([
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{latitude: 52.516272, longitude: 13.377722}, // Berlin
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{latitude: 51.515, longitude: 7.453619}, // Dortmund
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{latitude: 51.503333, longitude: -0.119722} // London
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]); // -> 945235</pre>
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<h3>geolib.getSpeed(coords, coords[, options])</h3>
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Calculates the speed between to points within a given time span.
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Returns the speed in <em>options.unit</em> (default is km/h).
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<h4>Example</h4>
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<pre>
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geolib.getSpeed(
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{lat: 51.567294, lng: 7.38896, time: 1360231200880},
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{lat: 52.54944, lng: 13.468509, time: 1360245600880},
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{unit: 'mph'}
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); // -> 66.9408 (mph)</pre>
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<h3>geolib.convertUnit(string unit, float distance[, int round])</h3>
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Converts a given distance (in meters) to another unit.
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<h4>Parameters</h4>
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`unit` can be one of:
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- m (meter)
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- km (kilometers)
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- cm (centimeters)
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- mm (millimeters)
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- mi (miles)
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- sm (seamiles)
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- ft (foot)
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- in (inch)
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- yd (yards)
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`distance` distance to be converted (source must be in meter)
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`round` fractional digits
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<h4>Example</h4>
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`geolib.convertUnit('km', 14213, 2) // -> 14,21`
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<h3>geolib.sexagesimal2decimal(string coord)</h3>
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Converts a sexagesimal coordinate to decimal format
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<h4>Example</h4>
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`geolib.sexagesimal2decimal("51° 29' 46\" N")`
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<h3>geolib.decimal2sexagesimal(float coord)</h3>
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Converts a decimal coordinate to sexagesimal format
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<h4>Example</h4>
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`geolib.decimal2sexagesimal(51.49611111); // -> 51° 29' 46.00`
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<h3>geolib.useDecimal(mixed coordinate)</h3>
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Checks if a coordinate is already in decimal format and, if not, converts it to
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<h4>Example</h4>
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<pre>geolib.useDecimal("51° 29' 46\" N"); // -> 51.59611111
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geolib.useDecimal(51.59611111) // -> 51.59611111</pre>
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