geojson-groupby

Group GeoJSON features or FeatureCollection based on associated properties and merge geometries to multigeometries.

installation

npm install geojson-groupby

usage

var geoGroupBy = require('geojson-groupby')
var group = geoGroupBy(array, properties [, collect])

• array Array of JSON objects

• properties Array JSON properties' path like address.city or lookup object

  lookup

  {
    intervals: array of numbers
    ,property: string
    [,labels: array of string]
  }

  intervals Array of intervals. Like [ 10, 20, 30, 40, 50] group the data in four ranges, whereas lower bound is inclusive and upper bound is exclusive.

  peroperty Property path like price

  labels Array of interval labels like [ 'low', 'medium', 'high']

• collect Array of properties that need to be collected in array

examples

data set

var features = [
  {
    "id": 1, "geometry": {"type": "Point", "coordinates": [10, 10]},
    "properties": {"color": "blue","price": 150,"address": {"city": "New York"}}
  }, {
    "id": 2, "geometry": {"type": "Point", "coordinates": [20, 20]},
    "properties": {"color": "green","price": 200,"address": {"city": "London"}}
  }, {
    "id": 3, "geometry": {"type": "Point", "coordinates": [30, 30]},
    "properties": {"color": "red","price": 210,"address": {"city": "London"}}
  }, {
    "id": 4, "geometry": {"type": "Point", "coordinates": [40, 40]},
    "properties": {"color": "red","price": 280,"address": {"city": "New York"}}
  }, {
    "id": 5, "geometry": {"type": "Point", "coordinates": [50, 50]},
    "properties": {"color": "green","price": 300,"address": {"city": "New York"}}
  }, {
    "id": 6, "geometry": {"type": "Point", "coordinates": [60, 60]},
    "properties": {"color": "red","price": 360,"address": {"city": "Mumbai"}}
  }
]
```

##### group features and merge geometries to multigeometries
```javascript
geoGroupBy(features, ['properties.color'])
// output as
{blue: {geometry: {type: 'MultiPoint', coordinates: [[10, 10]]}},
  green: {geometry: {type: 'MultiPoint', coordinates: [[20, 20], [50, 50]]}},
  red:
   {geometry:
      {type: 'MultiPoint',
        coordinates: [[30, 30], [40, 40], [60, 60]]}}}
```
##### group features, merge geometries to multigeometries and collect ids
```javascript
geoGroupBy(features, ['properties.color'],['id'])
// output as
{blue:
   {id: [1],
     geometry: {type: 'MultiPoint', coordinates: [[10, 10]]}},
  green:
   {id: [2, 5],
     geometry: {type: 'MultiPoint', coordinates: [[20, 20], [50, 50]]}},
  red:
   {id: [3, 4, 6],
     geometry:
      {type: 'MultiPoint',
        coordinates: [[30, 30], [40, 40], [60, 60]]}}}

```

This package `geojson-groupby` is based on [json-groupby](https://github.com/gagan-bansal/json-groupby), so please also check different [examples](https://github.com/gagan-bansal/json-groupby#examples) on usage of json-groupby
  
## developing
Once you run
 
```npm isntall```

then for running test 

```npm run test```

to create build

```npm run build```

## license
This project is licensed under the terms of the MIT license.