Query a Spatial Index
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Documents that contain spatial data can be queried by spatial queries that employ geographical criteria.
You have two options:-
Dynamic spatial query
Either make a dynamic spatial query on a collection (see how to make a spatial query).
An auto-index will be created by the server. -
Spatial index query
Or, index your documents' spatial data in a static-index (see indexing spatial data)
and then make a spatial query on this index ( described in this article ).
-
-
A few examples of querying a spatial index are provided below.
A spatial query performed on a static-index is similar to the dynamic spatial query.
Find all spatial API methods listed here. -
Examples in this page:
Search by radius
-
Query the spatial index:
-
Use the
withinRadius
method to search for all documents containing spatial data that is located
within the specified distance from the given center point.
// Define a spatial query on index 'Events/ByNameAndCoordinates'
const employeesWithinRadius = await session
.query({ indexName: "Events/ByNameAndCoordinates"})
// Call 'spatial' method
.spatial(
/// Pass the spatial index-field containing the spatial data
"coordinates",
// Set the geographical area in which to search for matching documents
// Call 'withinRadius', pass the radius and the center points coordinates
criteria => criteria.withinRadius(20, 47.623473, -122.3060097))
.all();
// The query returns all matching Event entities
// that are located within 20 kilometers radius
// from point (47.623473 latitude, -122.3060097 longitude).
// Define an index with a spatial field
class Events_ByNameAndCoordinates extends AbstractJavaScriptIndexCreationTask {
constructor() {
super();
const { createSpatialField } = this.mapUtils();
this.map('events', e => {
return {
name: e.Name,
// Call 'createSpatialField' to create a spatial index-field
// Field 'coordinates' will be composed of lat & lng supplied from the document
coordinates: createSpatialField(
e.latitude,
e.longitude
)
// Documents can be retrieved
// by making a spatial query on the 'coordinates' index-field
};
});
}
}
class Event {
constructor(id, name, latitude, longitude) {
this.id = id;
this.name = name;
this.latitude = latitude
this.longitude = longitude;
}
}
from index "Events/ByNameAndCoordinates"
where spatial.within(
Coordinates,
spatial.circle(20, 47.623473, -122.3060097)
)
// The query returns all matching Event entities
// that are located within 20 kilometers radius
// from point (47.623473 latitude, -122.3060097 longitude).
Search by shape
-
Query the spatial index:
Use therelatesToShape
method to search for all documents containing spatial data that is located
in the specified relation to the given shape. -
The shape in the query is specified as either a circle or a polygon in a WKT format.
See polygon rules here. -
The relation to the shape can be one of:
Within
,Contains
,Disjoint
,Intersects
. -
See more usage examples in the dynamic search by shape query.
// Define a spatial query on index 'EventsWithWKT/ByNameAndWKT'
const employeesWithinShape = await session
.query({ indexName: "EventsWithWKT/ByNameAndWKT" })
// Call 'spatial' method
.spatial(
// Pass the spatial index-field containing the spatial data
"wkt",
// Set the geographical search criteria, call 'relatesToShape'
criteria => criteria.relatesToShape(
// Specify the WKT string
`POLYGON ((
-118.6527948 32.7114894,
-95.8040242 37.5929338,
-102.8344151 53.3349629,
-127.5286633 48.3485664,
-129.4620208 38.0786067,
-118.7406746 32.7853769,
-118.6527948 32.7114894
))`,
// Specify the relation between the WKT shape and the documents spatial data
"Within"
))
.all();
// The query returns all matching Event entities
// that are located within the specified polygon.
// Define an index with a spatial field
class EventsWithWKT_ByNameAndWKT extends AbstractJavaScriptIndexCreationTask {
constructor() {
super();
const { createSpatialField } = this.mapUtils();
this.map('events', e => {
return {
name: e.Name,
// Call 'createSpatialField' to create a spatial index-field
// Field 'wkt' will be composed of the WKT string supplied from the document
wkt: createSpatialField(e.wkt)
// Documents can be retrieved by
// making a spatial query on the 'wkt' index-field
};
});
}
}
class EventWithWKT {
constructor(id, name, wkt) {
this.id = id;
this.name = name;
this.wkt = wkt;
}
}
from index "EventsWithWKT/ByNameAndWKT"
where spatial.within(
WKT,
spatial.wkt("POLYGON ((
-118.6527948 32.7114894,
-95.8040242 37.5929338,
-102.8344151 53.3349629,
-127.5286633 48.3485664,
-129.4620208 38.0786067,
-118.7406746 32.7853769,
-118.6527948 32.7114894))")
)
// The query returns all matching Event entities
// that are located within the specified polygon.
- Note:
The index in the above example indexes a WKT string in the spatial index-field.
However, you can query by shape also on spatial data that is indexed as lat/lng coordinates.
Sort results
-
Query the spatial index:
UseorderByDistance
ororderByDistanceDescending
to sort the results by distance from a given point. -
By default, distance in RavenDB measured in kilometers.
The distance can be rounded to a specific range.
// Define a spatial query on index 'Events_ByNameAndCoordinates'
const employeesSortedByDistance = await session
.query({ indexName: "Events/ByNameAndCoordinates" })
// Filter results by geographical criteria
.spatial(
"coordinates",
criteria => criteria.withinRadius(20, 47.623473, -122.3060097))
// Sort results, call 'orderByDistance'
.orderByDistance(
// Pass the spatial index-field containing the spatial data
"coordinates",
// Sort the results by their distance from this point:
47.623473, -122.3060097)
.all();
// Return all matching Event entities located within 20 kilometers radius
// from point (47.623473 latitude, -122.3060097 longitude).
// Sort the results by their distance from a specified point,
// the closest results will be listed first.
// Define an index with a spatial field
class Events_ByNameAndCoordinates extends AbstractJavaScriptIndexCreationTask {
constructor() {
super();
const { createSpatialField } = this.mapUtils();
this.map('events', e => {
return {
name: e.Name,
// Call 'createSpatialField' to create a spatial index-field
// Field 'coordinates' will be composed of lat & lng supplied from the document
coordinates: createSpatialField(
e.latitude,
e.longitude
)
// Documents can be retrieved
// by making a spatial query on the 'coordinates' index-field
};
});
}
}
class Event {
constructor(id, name, latitude, longitude) {
this.id = id;
this.name = name;
this.latitude = latitude
this.longitude = longitude;
}
}
from index "Events/ByNameAndCoordinates"
where spatial.within(
Coordinates,
spatial.circle(20, 47.623473, -122.3060097)
)
order by spatial.distance(
Coordinates,
spatial.point(47.623473, -122.3060097)
)
// The query returns all matching Event entities located within 20 kilometers radius
// from point (47.623473 latitude, -122.3060097 longitude).
// Sort the results by their distance from a specified point,
// the closest results will be listed first.
-
More sorting examples are available in the dynamic spatial query article.
-
To get the distance for each resulting entity see get resulting distance.