Session: Querying: How to Query a Spatial Index

Spatial indexes can be queried using the Spatial method which contains a full spectrum of spatial methods. The following article will cover these methods:

• Spatial
• OrderByDistance
• OrderByDistanceDescending

Spatial

IRavenQueryable<T> Spatial<T>(
  Expression<Func<T, object>> path,
  Func<SpatialCriteriaFactory, SpatialCriteria> clause);

IRavenQueryable<T> Spatial<T>(
  string fieldName,
  Func<SpatialCriteriaFactory, SpatialCriteria> clause);

IRavenQueryable<T> Spatial<T>(
  Func<DynamicSpatialFieldFactory<T>, DynamicSpatialField> field,
  Func<SpatialCriteriaFactory, SpatialCriteria> clause);

IRavenQueryable<T> Spatial<T>(
  DynamicSpatialField field,
  Func<SpatialCriteriaFactory, SpatialCriteria> clause);

Parameters
path	Expression<Func<T, object>>	Path to spatial field in an index
fieldName	string	Path to spatial field in an index
field	Func<DynamicSpatialFieldFactory<T>, DynamicSpatialField> or DynamicSpatialField	Factory or field that points to a dynamic field (used with auto-indexes). Either PointField or WktField
clause	Func<SpatialCriteriaFactory, SpatialCriteria>	Spatial criteria that will be executed on a given spatial field from the path parameter.

DynamicSpatialFieldFactory

PointField Point(
  Expression<Func<T, object>> latitudePath,
  Expression<Func<T, object>> longitudePath);

WktField Wkt(Expression<Func<T, object>> wktPath);

Parameters
latitudePath or longitudePath or wktPath	Expression<Func<T, object>>	Path to the field in a document containing either longitude, latitude or WKT

SpatialCriteriaFactory

SpatialCriteria RelatesToShape(
  string shapeWkt,
  SpatialRelation relation,
  double distErrorPercent = Constants.Documents.Indexing.Spatial.DefaultDistanceErrorPct);

SpatialCriteria RelatesToShape(
  string shapeWkt,
  SpatialRelation relation,
  SpatialUnits units,
  double distErrorPercent = Constants.Documents.Indexing.Spatial.DefaultDistanceErrorPct);

SpatialCriteria Intersects(
  string shapeWkt,
  double distErrorPercent = Constants.Documents.Indexing.Spatial.DefaultDistanceErrorPct);

SpatialCriteria Intersects(
  string shapeWkt,
  SpatialUnits units,
  double distErrorPercent = Constants.Documents.Indexing.Spatial.DefaultDistanceErrorPct);

SpatialCriteria Contains(
  string shapeWkt,
  double distErrorPercent = Constants.Documents.Indexing.Spatial.DefaultDistanceErrorPct);

SpatialCriteria Contains(
  string shapeWkt,
  SpatialUnits units,
  double distErrorPercent = Constants.Documents.Indexing.Spatial.DefaultDistanceErrorPct);

SpatialCriteria Disjoint(
  string shapeWkt,
  double distErrorPercent = Constants.Documents.Indexing.Spatial.DefaultDistanceErrorPct);

SpatialCriteria Disjoint(
  string shapeWkt,
  SpatialUnits units,
  double distErrorPercent = Constants.Documents.Indexing.Spatial.DefaultDistanceErrorPct);

SpatialCriteria Within(
  string shapeWkt,
  double distErrorPercent = Constants.Documents.Indexing.Spatial.DefaultDistanceErrorPct);

SpatialCriteria Within(
  string shapeWkt,
  SpatialUnits units,
  double distErrorPercent = Constants.Documents.Indexing.Spatial.DefaultDistanceErrorPct);

SpatialCriteria WithinRadius(
  double radius,
  double latitude,
  double longitude,
  SpatialUnits? radiusUnits = null,
  double distErrorPercent = Constants.Documents.Indexing.Spatial.DefaultDistanceErrorPct);

Parameters
shapeWkt	string	WKT-based shape to be used in operation
relation	SpatialRelation	Shape relation. Can be Within, Contains, Disjoint, Intersects
distErrorPercent	double	Maximum distance error tolerance in percents. Default: 0.025
radius or latitude or longitude	double	Used to define a radius circle
radiusUnits	SpatialUnits	Determines if circle should be calculated in Kilometers or Miles units

Example I

• Sync
• Async
• RQL

// return all matching entities
// within 10 kilometers radius
// from 32.1234 latitude and 23.4321 longitude coordinates
List<House> results = session
  .Query<House>()
  .Spatial(
      factory => factory.Point(x => x.Latitude, x => x.Longitude),
      criteria => criteria.WithinRadius(10, 32.1234, 23.4321))
  .ToList();

// return all matching entities
// within 10 kilometers radius
// from 32.1234 latitude and 23.4321 longitude coordinates
List<House> results = await asyncSession
  .Query<House>()
  .Spatial(
      factory => factory.Point(x => x.Latitude, x => x.Longitude),
      criteria => criteria.WithinRadius(10, 32.1234, 23.4321))
  .ToListAsync();

from Houses
where spatial.within(spatial.point(Latitude, Longitude), spatial.circle(10, 32.1234. 23.4321))

Example II

• Sync
• Async
• RQL

// return all matching entities
// within 10 kilometers radius
// from 32.1234 latitude and 23.4321 longitude coordinates
// this equals to WithinRadius(10, 32.1234, 23.4321)
List<House> results = session
  .Query<House>()
  .Spatial(
      factory => factory.Point(x => x.Latitude, x => x.Longitude),
      criteria => criteria.RelatesToShape("Circle(32.1234 23.4321 d=10.0000)", SpatialRelation.Within))
  .ToList();

// return all matching entities
// within 10 kilometers radius
// from 32.1234 latitude and 23.4321 longitude coordinates
// this equals to WithinRadius(10, 32.1234, 23.4321)
List<House> results = await asyncSession
  .Query<House>()
  .Spatial(
      factory => factory.Point(x => x.Latitude, x => x.Longitude),
      criteria => criteria.RelatesToShape("Circle(32.1234 23.4321 d=10.0000)", SpatialRelation.Within))
  .ToListAsync();

from Houses
where spatial.within(spatial.point(Latitude, Longitude), spatial.wkt('Circle(32.1234 23.4321 d=10.0000)'))

OrderByDistance

To sort by distance from given point use the OrderByDistance method. The closest results will come first.

// From point
IOrderedQueryable<T> OrderByDistance<T>(
  Func<DynamicSpatialFieldFactory<T>, DynamicSpatialField> field,
  double latitude,
  double longitude);

IOrderedQueryable<T> OrderByDistance<T>(
  DynamicSpatialField field,
  double latitude,
  double longitude);

IOrderedQueryable<T> OrderByDistance<T>(
  Expression<Func<T, object>> path,
  double latitude,
  double longitude);

IOrderedQueryable<T> OrderByDistance<T>(
  string fieldName,
  double latitude,
  double longitude);

// From center of WKT shape
IOrderedQueryable<T> OrderByDistance<T>(
  Func<DynamicSpatialFieldFactory<T>, DynamicSpatialField> field,
  string shapeWkt);

IOrderedQueryable<T> OrderByDistance<T>(
  DynamicSpatialField field,
  string shapeWkt);

IOrderedQueryable<T> OrderByDistance<T>(
  Expression<Func<T, object>> path,
  string shapeWkt);

IOrderedQueryable<T> OrderByDistance<T>(
  string fieldName,
  string shapeWkt);

// Rounding
IOrderedQueryable<T> OrderByDistance<T>(
  Expression<Func<T, object>> path,
  double latitude,
  double longitude,
  double roundFactor);

IOrderedQueryable<T> OrderByDistance<T>(
  string fieldName,
  double latitude,
  double longitude,
  double roundFactor);

IOrderedQueryable<T> OrderByDistance<T>(
  Expression<Func<T, object>> path,
  string shapeWkt,
  double roundFactor);

IOrderedQueryable<T> OrderByDistance<T>(
  string fieldName,
  string shapeWkt,
  double roundFactor);

Parameters
path	Expression<Func<T, object>>	Path to spatial field in index
fieldName	string	Path to spatial field in index
field	Func<DynamicSpatialFieldFactory<T>, DynamicSpatialField> or DynamicSpatialField	Factory or field that points to a dynamic field (used with auto-indexes). Either PointField or WktField
shapeWkt	string	WKT-based shape to be used as a point from which distance will be measured. If the shape is not a single point, then the center of the shape will be used as a reference.
latitude or longitude	double	Used to define a point from which distance will be measured

Example

• Sync
• Async
• RQL

// return all matching entities
// within 10 kilometers radius
// from 32.1234 latitude and 23.4321 longitude coordinates
// sort results by distance from 32.1234 latitude and 23.4321 longitude point
List<House> results = session
  .Query<House>()
  .Spatial(
      factory => factory.Point(x => x.Latitude, x => x.Longitude),
      criteria => criteria.WithinRadius(10, 32.1234, 23.4321))
  .OrderByDistance(
      factory => factory.Point(x => x.Latitude, x => x.Longitude), 32.1234, 23.4321)
  .ToList();

// return all matching entities
// within 10 kilometers radius
// from 32.1234 latitude and 23.4321 longitude coordinates
// sort results by distance from 32.1234 latitude and 23.4321 longitude point
List<House> results = await asyncSession
  .Query<House>()
  .Spatial(
      factory => factory.Point(x => x.Latitude, x => x.Longitude),
      criteria => criteria.WithinRadius(10, 32.1234, 23.4321))
  .OrderByDistance(
      factory => factory.Point(x => x.Latitude, x => x.Longitude), 32.1234, 23.4321)
  .ToListAsync();

from Houses
where spatial.within(spatial.point(Latitude, Longitude), spatial.circle(10, 32.1234. 23.4321))
order by spatial.distance(spatial.point(Latitude, Longitude), spatial.point(32.1234, 23.4321))

OrderByDistanceDescending

To sort by distance from given point use the OrderByDistanceDescending method. The farthest results will come first.

// From point
IOrderedQueryable<T> OrderByDistanceDescending<T>(
  Func<DynamicSpatialFieldFactory<T>, DynamicSpatialField> field,
  double latitude,
  double longitude);

IOrderedQueryable<T> OrderByDistanceDescending<T>(
  DynamicSpatialField field,
  double latitude,
  double longitude);

IOrderedQueryable<T> OrderByDistanceDescending<T>(
  Expression<Func<T, object>> path,
  double latitude,
  double longitude);

IOrderedQueryable<T> OrderByDistanceDescending<T>(
  string fieldName,
  double latitude,
  double longitude);

// From center of WKT shape
IOrderedQueryable<T> OrderByDistanceDescending<T>(
  Func<DynamicSpatialFieldFactory<T>, DynamicSpatialField> field,
  string shapeWkt);

IOrderedQueryable<T> OrderByDistanceDescending<T>(
  DynamicSpatialField field,
  string shapeWkt);

IOrderedQueryable<T> OrderByDistanceDescending<T>(
  Expression<Func<T, object>> path,
  string shapeWkt);

IOrderedQueryable<T> OrderByDistanceDescending<T>(
  string fieldName,
  string shapeWkt);

// Rounding
IOrderedQueryable<T> OrderByDistanceDescending<T>(
  Expression<Func<T, object>> path,
  double latitude,
  double longitude,
  double roundFactor);

IOrderedQueryable<T> OrderByDistanceDescending<T>(
  string fieldName,
  double latitude,
  double longitude,
  double roundFactor);

IOrderedQueryable<T> OrderByDistanceDescending<T>(
  Expression<Func<T, object>> path,
  string shapeWkt,
  double roundFactor);

IOrderedQueryable<T> OrderByDistanceDescending<T>(
  string fieldName,
  string shapeWkt,
  double roundFactor);

Parameters
path	Expression<Func<T, object>>	Path to spatial field in an index
fieldName	string	Path to spatial field in an index
field	Func<DynamicSpatialFieldFactory<T>, DynamicSpatialField> or DynamicSpatialField	Factory or field that points to a dynamic field (used with auto-indexes). Either PointField or WktField
shapeWkt	string	WKT-based shape to be used as a point from which distance will be measured. If the shape is not a single point, then the center of the shape will be used as a reference.
latitude or longitude	double	Used to define a point from which distance will be measured

Example

• Sync
• Async
• RQL

// return all matching entities
// within 10 kilometers radius
// from 32.1234 latitude and 23.4321 longitude coordinates
// sort results by distance from 32.1234 latitude and 23.4321 longitude point
List<House> results = session
  .Query<House>()
  .Spatial(
      factory => factory.Point(x => x.Latitude, x => x.Longitude),
      criteria => criteria.WithinRadius(10, 32.1234, 23.4321))
  .OrderByDistanceDescending(
      factory => factory.Point(x => x.Latitude, x => x.Longitude), 32.1234, 23.4321)
  .ToList();

// return all matching entities
// within 10 kilometers radius
// from 32.1234 latitude and 23.4321 longitude coordinates
// sort results by distance from 32.1234 latitude and 23.4321 longitude point
List<House> results = await asyncSession
  .Query<House>()
  .Spatial(
      factory => factory.Point(x => x.Latitude, x => x.Longitude),
      criteria => criteria.WithinRadius(10, 32.1234, 23.4321))
  .OrderByDistanceDescending(
      factory => factory.Point(x => x.Latitude, x => x.Longitude), 32.1234, 23.4321)
  .ToListAsync();

from Houses
where spatial.within(spatial.point(Latitude, Longitude), spatial.circle(10, 32.1234. 23.4321))
order by spatial.distance(spatial.point(Latitude, Longitude), spatial.point(32.1234, 23.4321)) desc

Remarks

By default, distances are measured in kilometers.