Fungsi Basisdata GeografisLink to this heading#

AreaLink to this heading#

class Area(expression, **extra)Link to this definition#

Tersedia: MySQL, Oracle, PostGIS, SpatiaLite

Accepts a single geographic field or expression and returns the area of the field as an Area measure.

MySQL and SpatiaLite without LWGEOM don't support area calculations on geographic SRSes.

AsGeoJSONLink to this heading#

class AsGeoJSON(expression, bbox=False, crs=False, precision=8, **extra)Link to this definition#

Ketersediaan: MySQL (≥ 5.7.5), PostGIS, SpatiaLite

Accepts a single geographic field or expression and returns a GeoJSON representation of the geometry. Note that the result is not a complete GeoJSON structure but only the geometry key content of a GeoJSON structure. See also Penserial GeoJSON.

Contoh:

>>> City.objects.annotate(json=AsGeoJSON('point')).get(name='Chicago').json
{"type":"Point","coordinates":[-87.65018,41.85039]}

AsGMLLink to this heading#

class AsGML(expression, version=2, precision=8, **extra)Link to this definition#

Tersedia: Oracle, PostGIS, SpatiaLite

Menerima bidang geografis tunggal atau pernyataan dan mengembalikan perwakilan Geographic Markup Language (GML) dari geometri.

Contoh:

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

AsKMLLink to this heading#

class AsKML(expression, precision=8, **extra)Link to this definition#

Tersedia: PostGIS, SpatiaLite

Menerima bidang geografis tunggal atau pernyataan dan mengembalikan perwakilan Keyhole Markup Language (KML) dari geometri.

Contoh:

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

AsSVGLink to this heading#

class AsSVG(expression, relative=False, precision=8, **extra)Link to this definition#

Tersedia: PostGIS, SpatiaLite

Menerima bidang geografis tunggal atau pernyataan dan mengembalikan sebuah perwakilan Scalable Vector Graphics (SVG) dari geometri.

AzimuthLink to this heading#

class Azimuth(point_a, point_b, **extra)Link to this definition#

Ketersediaan: PostGIS, SpatiaLite (LWGEOM)

Returns the azimuth in radians of the segment defined by the given point geometries, or None if the two points are coincident. The azimuth is angle referenced from north and is positive clockwise: north = 0; east = π/2; south = π; west = 3π/2.

BoundingCircleLink to this heading#

class BoundingCircle(expression, num_seg=48, **extra)Link to this definition#

Ketersediaan: PostGIS, Oracle

Accepts a single geographic field or expression and returns the smallest circle polygon that can fully contain the geometry.

Parameter num_seg hanya digunakan pada PostGIS.

CentroidLink to this heading#

class Centroid(expression, **extra)Link to this definition#

Tersedia: MySQL, PostGIS, Oracle, SpatiaLite

Menerima bidang geografis tunggal atau mengembalikan nilai centroid dari geometri.

DifferenceLink to this heading#

class Difference(expr1, expr2, **extra)Link to this definition#

Tersedia: MySQL (≥ 5.6.1), PostGIS, Oracle, SpatiaLite

Menerima dua bidang geografis atau pernyataan dan mengembalikan perbedaan geometri, yaitu bagian dari geometri A yang tidak berinteraksi dengan geometri B.

DistanceLink to this heading#

class Distance(expr1, expr2, spheroid=None, **extra)Link to this definition#

Tersedia: MySQL (≥ 5.6.1), PostGIS, Oracle, SpatiaLite

Accepts two geographic fields or expressions and returns the distance between them, as a Distance object. On MySQL, a raw float value is returned when the coordinates are geodetic.

On backends that support distance calculation on geodetic coordinates, the proper backend function is automatically chosen depending on the SRID value of the geometries (e.g. ST_DistanceSphere on PostGIS).

Ketika jarak dihitung dengan kordinat (bersiku-siku) geodetic, seperti halnya dengan awalan SRID WGS84 (4326), anda dapat menyetel argumen kata kunci spheroid untuk memutuskan jika perhitungan harus berdasarkan pada bulatan sederhana (kurang akurat, kurang sumber daya-intensif) atau pada sebuah berbentuk bola (lebih akurat, lebih sumber daya-intensif)

In the following example, the distance from the city of Hobart to every other PointField in the AustraliaCity queryset is calculated:

>>> from django.contrib.gis.db.models.functions import Distance
>>> pnt = AustraliaCity.objects.get(name='Hobart').point
>>> for city in AustraliaCity.objects.annotate(distance=Distance('point', pnt)):
...     print(city.name, city.distance)
Wollongong 990071.220408 m
Shellharbour 972804.613941 m
Thirroul 1002334.36351 m
...

EnvelopeLink to this heading#

class Envelope(expression, **extra)Link to this definition#

Tersedia: MySQL, PostGIS, SpatiaLite

Accepts a single geographic field or expression and returns the geometry representing the bounding box of the geometry.

ForceRHRLink to this heading#

class ForceRHR(expression, **extra)Link to this definition#

Tersedia: PostGIS

Accepts a single geographic field or expression and returns a modified version of the polygon/multipolygon in which all of the vertices follow the right-hand rule.

GeoHashLink to this heading#

class GeoHash(expression, precision=None, **extra)Link to this definition#

Ketersediaan: MySQL (≥ 5.7.5), PostGIS, SpatiaLite (LWGEOM)

Menerima bidang geografi tunggal atau pernyataan dan mengembalikan perwakilan GeoHash dari geometri.

Argumen kata kunci precision mengendalikan sejumlah karakter dalam hasilnya.

IntersectionLink to this heading#

class Intersection(expr1, expr2, **extra)Link to this definition#

Tersedia: MySQL (≥ 5.6.1), PostGIS, Oracle, SpatiaLite

Menerima dua bidang geografi dan pernyataan dan mengembalikan persimpangan geometri diantara mereka.

IsValidLink to this heading#

class IsValid(expr)Link to this definition#

Ketersediaan: MySQL (≥ 5.7.5), PostGIS, Oracle, SpatiaLite (LWGEOM)

Menerima sebuah bidang geografi atau pernyataan dan percobaan jika nilai berbentuk bagus. Mengembalikan True jika nilainya adalah geometri sah dan False sebaliknya.

LengthLink to this heading#

class Length(expression, spheroid=True, **extra)Link to this definition#

Tersedia: MySQL, Oracle, PostGIS, SpatiaLite

Accepts a single geographic linestring or multilinestring field or expression and returns its length as a Distance measure.

On PostGIS and SpatiaLite, when the coordinates are geodetic (angular), you can specify if the calculation should be based on a simple sphere (less accurate, less resource-intensive) or on a spheroid (more accurate, more resource-intensive) with the spheroid keyword argument.

MySQL tidak mendukung dukungan perhitungan panjang pada geografis SRS.

LineLocatePointLink to this heading#

class LineLocatePoint(linestring, point, **extra)Link to this definition#

Ketersediaan: PostGIS, SpatiaLite

Returns a float between 0 and 1 representing the location of the closest point on linestring to the given point, as a fraction of the 2D line length.

MakeValidLink to this heading#

class MakeValid(expr)Link to this definition#

Tersedia: PostGIS, SpatiaLite (LWGEOM)

Accepts a geographic field or expression and attempts to convert the value into a valid geometry without losing any of the input vertices. Geometries that are already valid are returned without changes. Simple polygons might become a multipolygon and the result might be of lower dimension than the input.

MemSizeLink to this heading#

class MemSize(expression, **extra)Link to this definition#

Tersedia: PostGIS

Accepts a single geographic field or expression and returns the memory size (number of bytes) that the geometry field takes.

NumGeometriesLink to this heading#

class NumGeometries(expression, **extra)Link to this definition#

Tersedia: MySQL, PostGIS, Oracle, SpatiaLite

Accepts a single geographic field or expression and returns the number of geometries if the geometry field is a collection (e.g., a GEOMETRYCOLLECTION or MULTI* field). Returns 1 for single geometries.

Pada MySQL, mengembalikan None untuk geometri tunggal.

NumPointsLink to this heading#

class NumPoints(expression, **extra)Link to this definition#

Tersedia: MySQL, PostGIS, Oracle, SpatiaLite

Accepts a single geographic field or expression and returns the number of points in a geometry.

Pada MySQL, mengembalikan None untuk geometri bukan-LINESTRING apapun.

PerimeterLink to this heading#

class Perimeter(expression, **extra)Link to this definition#

Tersedia: PostGIS, Oracle, SpatiaLite

Accepts a single geographic field or expression and returns the perimeter of the geometry field as a Distance object.

PointOnSurfaceLink to this heading#

class PointOnSurface(expression, **extra)Link to this definition#

Tersedia: PostGIS, Oracle, SpatiaLite

Accepts a single geographic field or expression and returns a Point geometry guaranteed to lie on the surface of the field; otherwise returns None.

ReverseLink to this heading#

class Reverse(expression, **extra)Link to this definition#

Tersedia: PostGIS, Oracle, SpatiaLite

Accepts a single geographic field or expression and returns a geometry with reversed coordinates.

ScaleLink to this heading#

class Scale(expression, x, y, z=0.0, **extra)Link to this definition#

Tersedia: PostGIS, SpatiaLite

Accepts a single geographic field or expression and returns a geometry with scaled coordinates by multiplying them with the x, y, and optionally z parameters.

SnapToGridLink to this heading#

class SnapToGrid(expression, *args, **extra)Link to this definition#

Tersedia: PostGIS, SpatiaLite

Accepts a single geographic field or expression and returns a geometry with all points snapped to the given grid. How the geometry is snapped to the grid depends on how many numeric (either float, integer, or long) arguments are given.

SymDifferenceLink to this heading#

class SymDifference(expr1, expr2, **extra)Link to this definition#

Tersedia: MySQL (≥ 5.6.1), PostGIS, Oracle, SpatiaLite

Accepts two geographic fields or expressions and returns the geometric symmetric difference (union without the intersection) between the given parameters.

TransformLink to this heading#

class Transform(expression, srid, **extra)Link to this definition#

Tersedia: PostGIS, Oracle, SpatiaLite

Accepts a geographic field or expression and a SRID integer code, and returns the transformed geometry to the spatial reference system specified by the srid parameter.

TranslateLink to this heading#

class Translate(expression, x, y, z=0.0, **extra)Link to this definition#

Tersedia: PostGIS, SpatiaLite

Accepts a single geographic field or expression and returns a geometry with its coordinates offset by the x, y, and optionally z numeric parameters.

UnionLink to this heading#

class Union(expr1, expr2, **extra)Link to this definition#

Tersedia: MySQL (≥ 5.6.1), PostGIS, Oracle, SpatiaLite

Menerima dua bidang geografi atau pernyataan dan mengembalikan gabungan dari kedua geometri.