Graphileon Documentation Graphileon.com

For Dashboard Designers APIs Geo-Spatial Index

Friday, November 11, 2022 12:52 PM

Geo-spatial index

Description

Using this API one can index a collection of polygons (usually geographic areas) then subsequently, very quickly, query for one (or multiple) point(s) what polygons contain that point.

This API uses FeatureCollection, Polygon and MultiPolygon GeoJSON structures

Limitations

  • Currently the index supports only one collection of polygons at a time.
  • The index is kept in memory so more polygons means more (server) memory used.
  • Index data is not saved on disk meaning that it will be lost when the Graphileon server is restarted.

Endpoints

Add features

Description: adds geographic polygons to the index

URL: /api/spatial-index/add-features

Method: POST

Parameters:

Key Description Type Possible values
type Type of GeoJSON data structure string FeatureCollection
features List of GeoJSON features. Only Polygon and MultiPolygon structures are indexed. array
<feature>.id or <feature>.properties.id Unique key to identify a specific feature in the index. This key will pe returned by query-points endpoint string / number

Response: true (success) when index was updated successfully

Clear

Description: empties the index (removes all indexed polygons)

URL: /api/spatial-index/clear

Method: GET

Parameters: none

Response: true (success) when index was updated successfully

Query points

Description: given an array of geographic points returns, for each point, the list of ids of the geographic polygons that contain the given point

URL: /api/spatial-index/query-points

Method: POST

Parameters:

Key Description Type Possible values
points Array of geographical positions (points) array
<point>.latitude Position of the point on the y axis float
<point>.longitude Position of the point on the x axis float

Response: for each point an array of Feature ids (already added to the index) that contain (intersect) with the point. (array of array of polygon ids)