# Django 1.8.18.dev20170123152445 documentation

# GeoQuerySet API Reference

class `GeoQuerySet`(model=None)

## Spatial Lookups

Just like when using the QuerySet API, interaction with `GeoQuerySet` by chaining filters. Instead of the regular Django Field lookups, the spatial lookups in this section are available for `GeometryField`.

For an introduction, see the spatial lookups introduction. For an overview of what lookups are compatible with a particular spatial backend, refer to the spatial lookup compatibility table.

### bbcontains

Availability: PostGIS, MySQL, SpatiaLite

Tests if the geometry field’s bounding box completely contains the lookup geometry’s bounding box.

Example:

    Zipcode.objects.filter(poly__bbcontains=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `poly ~ geom`
MySQL | `MBRContains(poly, geom)`
SpatiaLite | `MbrContains(poly, geom)`

### bboverlaps

Availability: PostGIS, MySQL, SpatiaLite

Tests if the geometry field’s bounding box overlaps the lookup geometry’s bounding box.

Example:

    Zipcode.objects.filter(poly__bboverlaps=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `poly && geom`
MySQL | `MBROverlaps(poly, geom)`
SpatiaLite | `MbrOverlaps(poly, geom)`

### contained

Availability: PostGIS, MySQL, SpatiaLite

Tests if the geometry field’s bounding box is completely contained by the lookup geometry’s bounding box.

Example:

    Zipcode.objects.filter(poly__contained=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `poly @ geom`
MySQL | `MBRWithin(poly, geom)`
SpatiaLite | `MbrWithin(poly, geom)`

### contains

Availability: PostGIS, Oracle, MySQL, SpatiaLite

Tests if the geometry field spatially contains the lookup geometry.

Example:

    Zipcode.objects.filter(poly__contains=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_Contains(poly, geom)`
Oracle | `SDO_CONTAINS(poly, geom)`
MySQL | `MBRContains(poly, geom)`
SpatiaLite | `Contains(poly, geom)`

### contains_properly

Availability: PostGIS

Returns true if the lookup geometry intersects the interior of the geometry field, but not the boundary (or exterior). [4]

Example:

    Zipcode.objects.filter(poly__contains_properly=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_ContainsProperly(poly, geom)`

### coveredby

Availability: PostGIS, Oracle

Tests if no point in the geometry field is outside the lookup geometry. [3]

Example:

    Zipcode.objects.filter(poly__coveredby=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_CoveredBy(poly, geom)`
Oracle | `SDO_COVEREDBY(poly, geom)`

### covers

Availability: PostGIS, Oracle

Tests if no point in the lookup geometry is outside the geometry field. [3]

Example:

    Zipcode.objects.filter(poly__covers=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_Covers(poly, geom)`
Oracle | `SDO_COVERS(poly, geom)`

### crosses

Availability: PostGIS, SpatiaLite

Tests if the geometry field spatially crosses the lookup geometry.

Example:

    Zipcode.objects.filter(poly__crosses=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_Crosses(poly, geom)`
SpatiaLite | `Crosses(poly, geom)`

### disjoint

Availability: PostGIS, Oracle, MySQL, SpatiaLite

Tests if the geometry field is spatially disjoint from the lookup geometry.

Example:

    Zipcode.objects.filter(poly__disjoint=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_Disjoint(poly, geom)`
Oracle | `SDO_GEOM.RELATE(poly, 'DISJOINT', geom, 0.05)`
MySQL | `MBRDisjoint(poly, geom)`
SpatiaLite | `Disjoint(poly, geom)`

### equals

Availability: PostGIS, Oracle, MySQL, SpatiaLite

### exact, same_as

Availability: PostGIS, Oracle, MySQL, SpatiaLite

### intersects

Availability: PostGIS, Oracle, MySQL, SpatiaLite

Tests if the geometry field spatially intersects the lookup geometry.

Example:

    Zipcode.objects.filter(poly__intersects=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_Intersects(poly, geom)`
Oracle | `SDO_OVERLAPBDYINTERSECT(poly, geom)`
MySQL | `MBRIntersects(poly, geom)`
SpatiaLite | `Intersects(poly, geom)`

### overlaps

Availability: PostGIS, Oracle, MySQL, SpatiaLite

### relate

Availability: PostGIS, Oracle, SpatiaLite

Tests if the geometry field is spatially related to the lookup geometry by the values given in the given pattern. This lookup requires a tuple parameter, `(geom, pattern)`; the form of `pattern` will depend on the spatial backend:

#### PostGIS & SpatiaLite

On these spatial backends the intersection pattern is a string comprising nine characters, which define intersections between the interior, boundary, and exterior of the geometry field and the lookup geometry. The intersection pattern matrix may only use the following characters: `1`, `2`, `T`, `F`, or `*`. This lookup type allows users to “fine tune” a specific geometric relationship consistent with the DE-9IM model. [1]

Example:

    # A tuple lookup parameter is used to specify the geometry and
    # the intersection pattern (the pattern here is for 'contains').
    Zipcode.objects.filter(poly__relate=(geom, 'T*T***FF*'))

PostGIS SQL equivalent:

    SELECT ... WHERE ST_Relate(poly, geom, 'T*T***FF*')

SpatiaLite SQL equivalent:

    SELECT ... WHERE Relate(poly, geom, 'T*T***FF*')

#### Oracle

Here the relation pattern is comprised at least one of the nine relation strings: `TOUCH`, `OVERLAPBDYDISJOINT`, `OVERLAPBDYINTERSECT`, `EQUAL`, `INSIDE`, `COVEREDBY`, `CONTAINS`, `COVERS`, `ON`, and `ANYINTERACT`. Multiple strings may be combined with the logical Boolean operator OR, for example, `'inside+touch'`. [2] The relation strings are case-insensitive.

Example:

    Zipcode.objects.filter(poly__relate=(geom, 'anyinteract'))

Oracle SQL equivalent:

    SELECT ... WHERE SDO_RELATE(poly, geom, 'anyinteract')

### touches

Availability: PostGIS, Oracle, MySQL, SpatiaLite

Tests if the geometry field spatially touches the lookup geometry.

Example:

    Zipcode.objects.filter(poly__touches=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_Touches(poly, geom)`
MySQL | `MBRTouches(poly, geom)`
Oracle | `SDO_TOUCH(poly, geom)`
SpatiaLite | `Touches(poly, geom)`

### within

Availability: PostGIS, Oracle, MySQL, SpatiaLite

Tests if the geometry field is spatially within the lookup geometry.

Example:

    Zipcode.objects.filter(poly__within=geom)

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_Within(poly, geom)`
MySQL | `MBRWithin(poly, geom)`
Oracle | `SDO_INSIDE(poly, geom)`
SpatiaLite | `Within(poly, geom)`

### left

Availability: PostGIS

Tests if the geometry field’s bounding box is strictly to the left of the lookup geometry’s bounding box.

Example:

    Zipcode.objects.filter(poly__left=geom)

PostGIS equivalent:

    SELECT ... WHERE poly << geom

### right

Availability: PostGIS

Tests if the geometry field’s bounding box is strictly to the right of the lookup geometry’s bounding box.

Example:

    Zipcode.objects.filter(poly__right=geom)

PostGIS equivalent:

    SELECT ... WHERE poly >> geom

### overlaps_left

Availability: PostGIS

Tests if the geometry field’s bounding box overlaps or is to the left of the lookup geometry’s bounding box.

Example:

    Zipcode.objects.filter(poly__overlaps_left=geom)

PostGIS equivalent:

    SELECT ... WHERE poly &< geom

### overlaps_right

Availability: PostGIS

Tests if the geometry field’s bounding box overlaps or is to the right of the lookup geometry’s bounding box.

Example:

    Zipcode.objects.filter(poly__overlaps_right=geom)

PostGIS equivalent:

    SELECT ... WHERE poly &> geom

### overlaps_above

Availability: PostGIS

Tests if the geometry field’s bounding box overlaps or is above the lookup geometry’s bounding box.

Example:

    Zipcode.objects.filter(poly__overlaps_above=geom)

PostGIS equivalent:

    SELECT ... WHERE poly |&> geom

### overlaps_below

Availability: PostGIS

Tests if the geometry field’s bounding box overlaps or is below the lookup geometry’s bounding box.

Example:

    Zipcode.objects.filter(poly__overlaps_below=geom)

PostGIS equivalent:

    SELECT ... WHERE poly &<| geom

### strictly_above

Availability: PostGIS

Tests if the geometry field’s bounding box is strictly above the lookup geometry’s bounding box.

Example:

    Zipcode.objects.filter(poly__strictly_above=geom)

PostGIS equivalent:

    SELECT ... WHERE poly |>> geom

### strictly_below

Availability: PostGIS

Tests if the geometry field’s bounding box is strictly below the lookup geometry’s bounding box.

Example:

    Zipcode.objects.filter(poly__strictly_below=geom)

PostGIS equivalent:

    SELECT ... WHERE poly <<| geom

## Distance Lookups

Availability: PostGIS, Oracle, SpatiaLite

For an overview on performing distance queries, please refer to the distance queries introduction.

Distance lookups take the following form:

    <field>__<distance lookup>=(<geometry>, <distance value>[, 'spheroid'])

The value passed into a distance lookup is a tuple; the first two values are mandatory, and are the geometry to calculate distances to, and a distance value (either a number in units of the field or a `Distance` object). On every distance lookup but `dwithin`, an optional third element, `'spheroid'`, may be included to tell GeoDjango to use the more accurate spheroid distance calculation functions on fields with a geodetic coordinate system (e.g., `ST_Distance_Spheroid` would be used instead of `ST_Distance_Sphere`).

### distance_gt

Returns models where the distance to the geometry field from the lookup geometry is greater than the given distance value.

Example:

    Zipcode.objects.filter(poly__distance_gt=(geom, D(m=5)))

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_Distance(poly, geom) > 5`
Oracle | `SDO_GEOM.SDO_DISTANCE(poly, geom, 0.05) > 5`
SpatiaLite | `Distance(poly, geom) > 5`

### distance_gte

Returns models where the distance to the geometry field from the lookup geometry is greater than or equal to the given distance value.

Example:

    Zipcode.objects.filter(poly__distance_gte=(geom, D(m=5)))

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_Distance(poly, geom) >= 5`
Oracle | `SDO_GEOM.SDO_DISTANCE(poly, geom, 0.05) >= 5`
SpatiaLite | `Distance(poly, geom) >= 5`

### distance_lt

Returns models where the distance to the geometry field from the lookup geometry is less than the given distance value.

Example:

    Zipcode.objects.filter(poly__distance_lt=(geom, D(m=5)))

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_Distance(poly, geom) < 5`
Oracle | `SDO_GEOM.SDO_DISTANCE(poly, geom, 0.05) < 5`
SpatiaLite | `Distance(poly, geom) < 5`

### distance_lte

Returns models where the distance to the geometry field from the lookup geometry is less than or equal to the given distance value.

Example:

    Zipcode.objects.filter(poly__distance_lte=(geom, D(m=5)))

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_Distance(poly, geom) <= 5`
Oracle | `SDO_GEOM.SDO_DISTANCE(poly, geom, 0.05) <= 5`
SpatiaLite | `Distance(poly, geom) <= 5`

### dwithin

Returns models where the distance to the geometry field from the lookup geometry are within the given distance from one another. Note that you can only provide `Distance` objects if the targeted geometries are in a projected system. For geographic geometries, you should use units of the geometry field (e.g. degrees for `WGS84`) .

Example:

    Zipcode.objects.filter(poly__dwithin=(geom, D(m=5)))

Backend | SQL Equivalent
--- | ---
PostGIS | `ST_DWithin(poly, geom, 5)`
Oracle | `SDO_WITHIN_DISTANCE(poly, geom, 5)`

Note

This lookup is not available on SpatiaLite.

## `GeoQuerySet` Methods

`GeoQuerySet` methods specify that a spatial operation be performed on each spatial operation on each geographic field in the queryset and store its output in a new attribute on the model (which is generally the name of the `GeoQuerySet` method).

There are also aggregate `GeoQuerySet` methods which return a single value instead of a queryset. This section will describe the API and availability of every `GeoQuerySet` method available in GeoDjango.

Note

What methods are available depend on your spatial backend. See the compatibility table for more details.

With a few exceptions, the following keyword arguments may be used with all `GeoQuerySet` methods:

Keyword Argument | Description
--- | ---
`field_name` | By default, `GeoQuerySet` methods use the first geographic field encountered in the model. This keyword should be used to specify another geographic field (e.g., `field_name='point2'`) when there are multiple geographic fields in a model. On PostGIS, the `field_name` keyword may also be used on geometry fields in models that are related via a `ForeignKey` relation (e.g., `field_name='related__point'`).
`model_att` | By default, `GeoQuerySet` methods typically attach their output in an attribute with the same name as the `GeoQuerySet` method. Setting this keyword with the desired attribute name will override this default behavior. For example, `qs = Zipcode.objects.centroid(model_att='c')` will attach the centroid of the `Zipcode` geometry field in a `c` attribute on every model rather than in a `centroid` attribute. This keyword is required if a method name clashes with an existing `GeoQuerySet` method – if you wanted to use the `area()` method on model with a `PolygonField` named `area`, for example.

### Measurement

Availability: PostGIS, Oracle, SpatiaLite

#### `area`

`GeoQuerySet.``area`(**kwargs)

Returns the area of the geographic field in an `area` attribute on each element of this GeoQuerySet.

#### `distance`

`GeoQuerySet.``distance`(geom, **kwargs)

This method takes a geometry as a parameter, and attaches a `distance` attribute to every model in the returned queryset that contains the distance (as a `Distance` object) to the given geometry.

In the following example (taken from the GeoDjango distance tests), the distance from the Tasmanian city of Hobart to every other `PointField` in the `AustraliaCity` queryset is calculated:

    >>> pnt = AustraliaCity.objects.get(name='Hobart').point
    >>> for city in AustraliaCity.objects.distance(pnt): print(city.name, city.distance)
    Wollongong 990071.220408 m
    Shellharbour 972804.613941 m
    Thirroul 1002334.36351 m
    Mittagong 975691.632637 m
    Batemans Bay 834342.185561 m
    Canberra 598140.268959 m
    Melbourne 575337.765042 m
    Sydney 1056978.87363 m
    Hobart 0.0 m
    Adelaide 1162031.83522 m
    Hillsdale 1049200.46122 m

Note

Because the `distance` attribute is a `Distance` object, you can easily express the value in the units of your choice. For example, `city.distance.mi` is the distance value in miles and `city.distance.km` is the distance value in kilometers. See Measurement Objects for usage details and the list of Supported units.

#### `length`

`GeoQuerySet.``length`(**kwargs)

Returns the length of the geometry field in a `length` attribute (a `Distance` object) on each model in the queryset.

#### `perimeter`

`GeoQuerySet.``perimeter`(**kwargs)

Returns the perimeter of the geometry field in a `perimeter` attribute (a `Distance` object) on each model in the queryset.

### Geometry Relationships

The following methods take no arguments, and attach geometry objects each element of the `GeoQuerySet` that is the result of relationship function evaluated on the geometry field.

#### `centroid`

`GeoQuerySet.``centroid`(**kwargs)

Availability: PostGIS, Oracle, SpatiaLite

Returns the `centroid` value for the geographic field in a `centroid` attribute on each element of the `GeoQuerySet`.

#### `envelope`

`GeoQuerySet.``envelope`(**kwargs)

Availability: PostGIS, SpatiaLite

Returns a geometry representing the bounding box of the geometry field in an `envelope` attribute on each element of the `GeoQuerySet`.

#### `point_on_surface`

`GeoQuerySet.``point_on_surface`(**kwargs)

Availability: PostGIS, Oracle, SpatiaLite

Returns a Point geometry guaranteed to lie on the surface of the geometry field in a `point_on_surface` attribute on each element of the queryset; otherwise sets with None.

### Geometry Editors

#### `force_rhr`

`GeoQuerySet.``force_rhr`(**kwargs)

Availability: PostGIS

Returns a modified version of the polygon/multipolygon in which all of the vertices follow the Right-Hand-Rule, and attaches as a `force_rhr` attribute on each element of the queryset.

#### `reverse_geom`

`GeoQuerySet.``reverse_geom`(**kwargs)

Availability: PostGIS, Oracle

Reverse the coordinate order of the geometry field, and attaches as a `reverse` attribute on each element of the queryset.

#### `scale`

`GeoQuerySet.``scale`(x, y, z=0.0, **kwargs)

Availability: PostGIS, SpatiaLite

#### `snap_to_grid`

`GeoQuerySet.``snap_to_grid`(*args, **kwargs)

Snap all points of the input geometry to the grid. How the geometry is snapped to the grid depends on how many numeric (either float, integer, or long) arguments are given.

Number of Arguments | Description
--- | ---
1 | A single size to snap bot the X and Y grids to.
2 | X and Y sizes to snap the grid to.
4 | X, Y sizes and the corresponding X, Y origins.

#### `transform`

`GeoQuerySet.``transform`(srid=4326, **kwargs)

Availability: PostGIS, Oracle, SpatiaLite

The `transform` method transforms the geometry field of a model to the spatial reference system specified by the `srid` parameter. If no `srid` is given, then 4326 (WGS84) is used by default.

Note

Unlike other `GeoQuerySet` methods, `transform` stores its output “in-place”. In other words, no new attribute for the transformed geometry is placed on the models.

Note

What spatial reference system an integer SRID corresponds to may depend on the spatial database used. In other words, the SRID numbers used for Oracle are not necessarily the same as those used by PostGIS.

Example:

    >>> qs = Zipcode.objects.all().transform() # Transforms to WGS84
    >>> qs = Zipcode.objects.all().transform(32140) # Transforming to "NAD83 / Texas South Central"
    >>> print(qs[0].poly.srid)
    32140
    >>> print(qs[0].poly)
    POLYGON ((234055.1698884720099159 4937796.9232223574072123 ...

#### `translate`

`GeoQuerySet.``translate`(x, y, z=0.0, **kwargs)

Availability: PostGIS, SpatiaLite

Translates the geometry field to a new location using the given numeric parameters as offsets.

### Geometry Operations

Availability: PostGIS, Oracle, SpatiaLite

The following methods all take a geometry as a parameter and attach a geometry to each element of the `GeoQuerySet` that is the result of the operation.

#### `difference`

`GeoQuerySet.``difference`(geom)

Returns the spatial difference of the geographic field with the given geometry in a `difference` attribute on each element of the `GeoQuerySet`.

#### `intersection`

`GeoQuerySet.``intersection`(geom)

Returns the spatial intersection of the geographic field with the given geometry in an `intersection` attribute on each element of the `GeoQuerySet`.

#### `sym_difference`

`GeoQuerySet.``sym_difference`(geom)

Returns the symmetric difference of the geographic field with the given geometry in a `sym_difference` attribute on each element of the `GeoQuerySet`.

#### `union`

`GeoQuerySet.``union`(geom)

Returns the union of the geographic field with the given geometry in an `union` attribute on each element of the `GeoQuerySet`.

### Geometry Output

The following `GeoQuerySet` methods will return an attribute that has the value of the geometry field in each model converted to the requested output format.

#### `geohash`

`GeoQuerySet.``geohash`(precision=20, **kwargs)

Attaches a `geohash` attribute to every model the queryset containing the GeoHash representation of the geometry.

#### `geojson`

`GeoQuerySet.``geojson`(**kwargs)

Availability: PostGIS, SpatiaLite

Attaches a `geojson` attribute to every model in the queryset that contains the GeoJSON representation of the geometry.

Keyword Argument | Description
--- | ---
`precision` | It may be used to specify the number of significant digits for the coordinates in the GeoJSON representation – the default value is 8.
`crs` | Set this to `True` if you want the coordinate reference system to be included in the returned GeoJSON.
`bbox` | Set this to `True` if you want the bounding box to be included in the returned GeoJSON.

#### `gml`

`GeoQuerySet.``gml`(**kwargs)

Availability: PostGIS, Oracle, SpatiaLite

Attaches a `gml` attribute to every model in the queryset that contains the Geographic Markup Language (GML) representation of the geometry.

Example:

    >>> qs = Zipcode.objects.all().gml()
    >>> print(qs[0].gml)
    <gml:Polygon srsName="EPSG:4326"><gml:OuterBoundaryIs>-147.78711,70.245363 ...  -147.78711,70.245363</gml:OuterBoundaryIs></gml:Polygon>

Keyword Argument | Description
--- | ---
`precision` | This keyword is for PostGIS only. It may be used to specify the number of significant digits for the coordinates in the GML representation – the default value is 8.
`version` | This keyword is for PostGIS only. It may be used to specify the GML version used, and may only be values of 2 or 3. The default value is 2.

#### `kml`

`GeoQuerySet.``kml`(**kwargs)

Availability: PostGIS, SpatiaLite

Attaches a `kml` attribute to every model in the queryset that contains the Keyhole Markup Language (KML) representation of the geometry fields. It should be noted that the contents of the KML are transformed to WGS84 if necessary.

Example:

    >>> qs = Zipcode.objects.all().kml()
    >>> print(qs[0].kml)
    <Polygon><outerBoundaryIs><LinearRing><coordinates>-103.04135,36.217596,0 ... -103.04135,36.217596,0</coordinates></LinearRing></outerBoundaryIs></Polygon>

Keyword Argument | Description
--- | ---
`precision` | This keyword may be used to specify the number of significant digits for the coordinates in the KML representation – the default value is 8.

#### `svg`

`GeoQuerySet.``svg`(**kwargs)

Availability: PostGIS, SpatiaLite

Attaches a `svg` attribute to every model in the queryset that contains the Scalable Vector Graphics (SVG) path data of the geometry fields.

Keyword Argument | Description
--- | ---
`relative` | If set to `True`, the path data will be implemented in terms of relative moves. Defaults to `False`, meaning that absolute moves are used instead.
`precision` | This keyword may be used to specify the number of significant digits for the coordinates in the SVG representation – the default value is 8.

### Miscellaneous

#### `mem_size`

`GeoQuerySet.``mem_size`(**kwargs)

Availability: PostGIS

Returns the memory size (number of bytes) that the geometry field takes in a `mem_size` attribute on each element of the `GeoQuerySet`.

#### `num_geom`

`GeoQuerySet.``num_geom`(**kwargs)

Availability: PostGIS, Oracle, SpatiaLite

Returns the number of geometries in a `num_geom` attribute on each element of the `GeoQuerySet` if the geometry field is a collection (e.g., a `GEOMETRYCOLLECTION` or `MULTI*` field); otherwise sets with `None`.

#### `num_points`

`GeoQuerySet.``num_points`(**kwargs)

Availability: PostGIS, Oracle, SpatiaLite

Returns the number of points in the first linestring in the geometry field in a `num_points` attribute on each element of the `GeoQuerySet`; otherwise sets with `None`.

## Spatial Aggregates

### Aggregate Methods

Deprecated since version 1.8: Aggregate methods are now deprecated. Prefer using their function-based equivalents.

#### `collect`

`GeoQuerySet.``collect`(**kwargs)

Deprecated since version 1.8: Use the `Collect` aggregate instead.

Shortcut for `aggregate(Collect(<field>))`.

#### `extent`

`GeoQuerySet.``extent`(**kwargs)

Deprecated since version 1.8: Use the `Extent` aggregate instead.

Shortcut for `aggregate(Extent(<field>))`.

#### `extent3d`

`GeoQuerySet.``extent3d`(**kwargs)

Deprecated since version 1.8: Use the `Extent` aggregate instead.

Shortcut for `aggregate(Extent3D(<field>))`.

#### `make_line`

`GeoQuerySet.``make_line`(**kwargs)

Deprecated since version 1.8: Use the `MakeLine` aggregate instead.

Shortcut for `aggregate(MakeLine(<field>))`.

#### `unionagg`

`GeoQuerySet.``unionagg`(**kwargs)

Deprecated since version 1.8: Use the `Union` aggregate instead.

Shortcut for `aggregate(Union(<field>))`.

### Aggregate Functions

Django provides some GIS-specific aggregate functions. For details on how to use these aggregate functions, see the topic guide on aggregation.

Keyword Argument | Description
--- | ---
`tolerance` | This keyword is for Oracle only. It is for the tolerance value used by the `SDOAGGRTYPE` procedure; the Oracle documentation has more details.

Example:

    >>> from django.contrib.gis.db.models import Extent, Union
    >>> WorldBorder.objects.aggregate(Extent('mpoly'), Union('mpoly'))

#### `Collect`

class `Collect`(geo_field)

Availability: PostGIS, Spatialite (≥3.0)

Returns a `GEOMETRYCOLLECTION` or a `MULTI` geometry object from the geometry column. This is analogous to a simplified version of the `Union` aggregate, except it can be several orders of magnitude faster than performing a union because it simply rolls up geometries into a collection or multi object, not caring about dissolving boundaries.

#### `Extent`

class `Extent`(geo_field)

Availability: PostGIS, Oracle, Spatialite (≥3.0)

Returns the extent of all `geo_field` in the `QuerySet` as a four-tuple, comprising the lower left coordinate and the upper right coordinate.

Example:

    >>> qs = City.objects.filter(name__in=('Houston', 'Dallas')).aggregate(Extent('poly'))
    >>> print(qs['poly__extent'])
    (-96.8016128540039, 29.7633724212646, -95.3631439208984, 32.782058715820)

#### `Extent3D`

class `Extent3D`(geo_field)

Availability: PostGIS

Returns the 3D extent of all `geo_field` in the `QuerySet` as a six-tuple, comprising the lower left coordinate and upper right coordinate (each with x, y, and z coordinates).

Example:

    >>> qs = City.objects.filter(name__in=('Houston', 'Dallas')).aggregate(Extent3D('poly'))
    >>> print(qs['poly__extent3d'])
    (-96.8016128540039, 29.7633724212646, 0, -95.3631439208984, 32.782058715820, 0)

#### `MakeLine`

class `MakeLine`(geo_field)

Availability: PostGIS

Returns a `LineString` constructed from the point field geometries in the `QuerySet`. Currently, ordering the queryset has no effect.

Example:

    >>> print(City.objects.filter(name__in=('Houston', 'Dallas')
    ...      ).aggregate(MakeLine('poly'))['poly__makeline']
    LINESTRING (-95.3631510000000020 29.7633739999999989, -96.8016109999999941 32.7820570000000018)

#### `Union`

class `Union`(geo_field)

Availability: PostGIS, Oracle, SpatiaLite

This method returns a `GEOSGeometry` object comprising the union of every geometry in the queryset. Please note that use of `Union` is processor intensive and may take a significant amount of time on large querysets.

Note

If the computation time for using this method is too expensive, consider using `Collect` instead.

Example:

    >>> u = Zipcode.objects.aggregate(Union(poly))  # This may take a long time.
    >>> u = Zipcode.objects.filter(poly__within=bbox).aggregate(Union(poly))  # A more sensible approach.

Footnotes

[1] | See OpenGIS Simple Feature Specification For SQL, at Ch. 2.1.13.2, p. 2-13 (The Dimensionally Extended Nine-Intersection Model).

[2] | See SDO_RELATE documentation, from Ch. 11 of the Oracle Spatial User’s Guide and Manual.

[3] | (1, 2) For an explanation of this routine, read Quirks of the “Contains” Spatial Predicate by Martin Davis (a PostGIS developer).

[4] | Refer to the PostGIS `ST_ContainsProperly` documentation for more details.