mirror of https://gitee.com/bigwinds/arangodb
56 lines
2.0 KiB
Plaintext
56 lines
2.0 KiB
Plaintext
!CHAPTER Geo Queries
|
|
|
|
The ArangoDB allows to select documents based on geographic coordinates. In
|
|
order for this to work, a geo-spatial index must be defined. This index will
|
|
use a very elaborate algorithm to lookup neighbors that is a magnitude faster
|
|
than a simple R* index.
|
|
|
|
In general a geo coordinate is a pair of latitude and longitude, which must
|
|
both be specified as numbers. A geo index can be created on coordinates that
|
|
are stored in a single list attribute with two elements like *[-10, +30]*
|
|
(latitude first, followed by longitude) or on coordinates stored in two
|
|
separate attributes.
|
|
|
|
For example, to index the following documents, an index can be created on the
|
|
*position* attribute of the documents:
|
|
|
|
db.test.save({ position: [ -10, 30 ] });
|
|
db.test.save({ position: [ 10, 45.5 ] });
|
|
|
|
db.test.ensureIndex({ type: "geo", fields: [ "position" ] });
|
|
|
|
If coordinates are stored in two distinct attributes, the index must be created
|
|
on the two attributes:
|
|
|
|
db.test.save({ latitude: -10, longitude: 30 });
|
|
db.test.save({ latitude: 10, longitude: 45.5 });
|
|
|
|
db.test.ensureIndex({ type: "geo", fields: [ "latitude", "longitude" ] });
|
|
|
|
In order to find all documents within a given radius around a coordinate use
|
|
the *within* operator. In order to find all documents near a given document
|
|
use the *near* operator.
|
|
|
|
It is possible to define more than one geo-spatial index per collection. In
|
|
this case you must give a hint using the *geo* operator which of indexes
|
|
should be used in a query.
|
|
|
|
!SUBSECTION Near
|
|
<!-- js/common/modules/@arangodb/arango-collection-common.js-->
|
|
@startDocuBlock collectionNear
|
|
|
|
!SUBSECTION Within
|
|
<!-- js/common/modules/@arangodb/arango-collection-common.js-->
|
|
@startDocuBlock collectionWithin
|
|
|
|
!SUBSECTION Geo
|
|
<!-- js/common/modules/@arangodb/arango-collection-common.js-->
|
|
@startDocuBlock collectionGeo
|
|
|
|
!SUBSECTION Related topics
|
|
|
|
Other ArangoDB geographic features are described in:
|
|
- [AQL Geo functions](../../../AQL/Functions/Geo.html)
|
|
- [Geo indexes](../../Indexing/Geo.md)
|
|
|