loopback-datatype-geopoint

Overview

The Geopoint object is a LoopBack data type that represents a physical location.

loopback-datasource-juggler and strong-remoting modules use this object to facilitate use of GeoPoint data type in a LoopBack model properties & remote methods.

$3

For example, to create a GeoPoint object in LoopBack:

``javascript
var loopback = require(‘loopback’);
var here = new loopback.GeoPoint({lat: 10.32424, lng: 5.84978});
`

The constructor requires two values:
- lat: Latitude point in degrees. Range: -90 to 90.
- lng: Longitude point in degrees. Range: -180 to 180

Call the constructor with any of the following arguments:
- Two numbers, for example new GeoPoint(10.32, 5.84)
- Number string of form "_lat_, _lng_", for example new GeoPoint('10.32, 5.84')
- Array with two number elements: [lat, lng], for example new GeoPoint([10.32, 5.84])
- Object with two number properties: lat and lng, for example new GeoPoint({ lat: 10.32, lng: 5.84})

$3

- in a LoopBack Model:

Declare a GeoPoint property in the model JSON file, for example:

`json
...
"properties": {
"location": {
"type": "GeoPoint"
},
...
}
...
`

or programtically:

`javascript
var CoffeeShop = loopback.createModel('coffee-shop', {
location: 'GeoPoint'
});
`

- in remote methods:

'accepts' & 'returns' argument types, for remote method, can be set to GeoPoint type, for example, in a remote method getNearbyLocation for model MyModel:

common/models/my-model.js
`javascript
MyModel.remoteMethod('getNearbyLocation', {
accepts: {arg: 'loc', type: 'GeoPoint'},
returns: {arg: 'location', type: 'GeoPoint'}
});
`

$3


- distanceBetween(pointA, pointB, options):

Determine the spherical distance between two GeoPoints

Arguments:

| Name | Type | Description |
|----------|-------------|-----------|
| pointA | GeoPoint | Point A|
| pointB | GeoPoint | Point B|
| options | Object | Options object with one key, 'type'. See below.|

Options:

| Name | Type | Description |
|:---------:|:------:|-----------|
| type | String | Unit of measurement, one of:
miles (default)
radians
kilometers
meters
miles
feet
degrees |

$3

- geoPoint.distanceTo(point, options):

Determine the spherical distance to the given point.

For example:
`javascript
var loopback = require(‘loopback’);

var here = new loopback.GeoPoint({lat: 10, lng: 10});
var there = new loopback.GeoPoint({lat: 5, lng: 5});

console.log(here.distanceTo(there, {type: 'miles'})); // result: 438
`

Arguments:

| Name | Type | Description |
|----------|-------------|-----------|
| point | GeoPoint | GeoPoint object to which to measure distance. |
| options | Object | Options object with one key, 'type'. Same as options in distanceBetween()|

- geoPoint.toString():
Simple serialization of geoPoint`.