https://github.com/nestrom/geojson-lookup

Lookup Geojson feature collections by indexing them by feature properties and by a GeoIndex for polygons to find polygons by a point
https://github.com/nestrom/geojson-lookup

Last synced: 3 months ago
JSON representation

Lookup Geojson feature collections by indexing them by feature properties and by a GeoIndex for polygons to find polygons by a point

• Host: GitHub
• URL: https://github.com/nestrom/geojson-lookup
• Owner: nestrom
• License: mit
• Created: 2017-02-13T11:52:11.000Z (almost 8 years ago)
• Default Branch: master
• Last Pushed: 2017-02-15T08:13:00.000Z (almost 8 years ago)
• Last Synced: 2024-04-26T17:45:08.537Z (9 months ago)
• Language: JavaScript
• Size: 23.4 KB
• Stars: 9
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-jordan - geojson-lookup - Lookup Geojson feature collections by indexing them by feature properties (INDEX TABLES) and by a Geometry (R-TREE) all in memory. (NodeJS / Gists)

README

        
![Build](https://api.travis-ci.org/nestrom/geojson-lookup.svg?branch=master)

![Build](https://nodei.co/npm/geojson-lookup.png)

# geojson-lookup

ITS ALL ABOUT SPEED and no alteration to your GEOJSONs 

Lookup Geojson feature collections by indexing them by feature properties (INDEX TABLES) and by a Geometry (R-TREE) all in memory.

###Usage 

1) Install through npm

`npm install geojson-lookup`

2) Require the module 

`var geoIndex = require("geojson-lookup");`

3) Initialize by passing Properties to indexBy and by passing a geoJson

 `var geo = geoIndex.buildIndex([ PROPERTIES_TO_INDEX ],GEOJSON_OBJECT);`

 

 example:  

 `var geo = geoIndex.buildIndex(["areaType","parentId"],geojs);`

 

 4) Query your polygon by indexed property 

 

 - Start by creating an instance of the Querying mechanism `var geoQuery = new geoIndex.Queries();`

 - Call the query method on the instantiated object as `.query(INDEXED_PROPERTY, OPERATOR("==" or "!="), VALUE_TO_QUERY)`

 - Now you can chain `.and()` , `or.()` to your query with the same parameter as `.query()` 

 - Once done call the method `.get()` to get your results as an `[ ARRAY_OF_FEATURES ]`  

 

 example:  

 `var resByProp = (geoQuery.query("areaType", "!=" ,'1').and("parentId", "=", "null").or("areaType","=","3").get());`

 

 5) You can query by Lattitude and Longitude 

 

 `geoQuery.getByPoint(LAT, LONG)`

 

 example:  

 `var resByPoint = geoQuery.getByPoint(28.98066, 36.25222);`

 

 returns `[ ARRAY_OF_FEATURES ]`