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https://github.com/flavors/django-graphql-geojson

GeoJSON support for Graphene Django
https://github.com/flavors/django-graphql-geojson

django filters geodjango geojson gis graphene graphql maps

Last synced: 19 days ago
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GeoJSON support for Graphene Django

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Django GraphQL GeoJSON
======================

|Pypi| |Wheel| |Build Status| |Codecov| |Code Climate|

`GeoJSON`_ support for `Django GraphQL`_

.. _GeoJSON: http://geojson.org
.. _Django GraphQL: https://github.com/graphql-python/graphene-django

Dependencies
------------

* Python ≥ 3.4
* Django ≥ 1.11

Installation
------------

Install last stable version from Pypi.

.. code:: sh

pip install django-graphql-geojson

GeoJSONType
-----------

``GeoJSONType`` is a subclass of ``DjangoObjectType`` which provides GraphQL fields in **GeoJSON** format.

Just define a ``Meta.geojson_field`` to be represented as a ``Geometry`` type.

**models.py**

.. code:: python

from django.contrib.gis.db import models

class Place(models.Model):
name = models.CharField(max_length=255)
location = models.PointField()

**schema.py**

.. code:: python

import graphene
import graphql_geojson

class PlaceType(graphql_geojson.GeoJSONType):

class Meta:
model = models.Place
geojson_field = 'location'

class Query(graphene.ObjectType):
places = graphene.List(PlaceType)

schema = graphene.Schema(query=Query)

**Query**

.. code:: graphql

query {
places {
id
type
geometry {
type
coordinates
}
bbox
properties {
name
}
}
}

Geometry Type
-------------

``Geometry`` is a special GraphQL type that represents a `GEOS geometry object`_.

.. _GEOS geometry object: https://docs.djangoproject.com/en/2.0/ref/contrib/gis/geos/#geometry-objects

**schema.py**

.. code:: python

import graphene
import graphql_geojson

class CreatePlace(graphene.Mutation):
place = graphene.Field(types.PlaceType)

class Arguments:
name = graphene.String(required=True)
location = graphql_geojson.Geometry(required=True)

@classmethod
def mutate(cls, root, info, **args):
place = models.Place.objects.create(**args)
return cls(place=place)

**Mutation**

.. code:: graphql

mutation CreatePlace($name: String!, $location: Geometry!) {
createPlace(name: $name, location: $location) {
place {
id
}
}
}

``Geometry`` type may be initialized in a few ways:

- Well-known text (WKT):

.. code:: python

"POINT(5 23)"

- Hexadecimal (HEX):

.. code:: python

"010100000000000000000014400000000000003740"

- GeoJSON:

.. code:: python

{
"type": "Point",
"coordinates": [5, 23]
}

GeometryFilterSet
-----------------

Django GraphQL GeoJSON provides a custom FilterSet for `spatial lookups`_.

.. _spatial lookups: https://docs.djangoproject.com/en/2.0/ref/contrib/gis/geoquerysets/#spatial-lookups

The ``Meta.fields`` option is combined with model to automatically generate filters.

**filters.py**

.. code:: python

from graphql_geojson.filters import GeometryFilterSet

class PlaceFilter(GeometryFilterSet):

class Meta:
model = models.Place
fields = {
'name': ['exact'],
'location': ['exact', 'intersects', 'distance_lte'],
}

**schema.py**

.. code:: python

import graphene
import graphql_geojson
from graphene import relay
from graphene_django.filter import DjangoFilterConnectionField

class PlaceNode(graphql_geojson.GeoJSONType):

class Meta:
model = Place
interfaces = [relay.Node]
geojson_field = 'location'

class Query(graphene.ObjectType):
places = DjangoFilterConnectionField(
PlaceNode,
filterset_class=PlaceFilter)

**Query**

.. code:: graphql

query Places($geometry: Geometry!){
places(location_Intersects: $geometry) {
edges {
node {
id
}
}
}
}

`Distance lookups`_ take a ``Distance`` parameter comprising:

- The desired `unit attribute`_ name
- Distance value
- A geometry to base calculations from

.. _Distance lookups: https://docs.djangoproject.com/en/2.0/ref/contrib/gis/db-api/#distance-lookups
.. _unit attribute: https://docs.djangoproject.com/en/2.0/ref/contrib/gis/measure/#supported-units

.. code:: graphql

query Places(
$unit: DistanceUnitEnum!,
$value: Float!,
$geometry: Geometry!)
{
places(location_DistanceLte: {
unit: $unit,
value: $value,
geometry: $geometry
}) {
edges {
node {
id
}
}
}
}

----

.. raw:: html



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:target: https://pypi.python.org/pypi/django-graphql-geojson

.. |Wheel| image:: https://img.shields.io/pypi/wheel/django-graphql-geojson.svg
:target: https://pypi.python.org/pypi/django-graphql-geojson

.. |Build Status| image:: https://travis-ci.org/flavors/django-graphql-geojson.svg?branch=master
:target: https://travis-ci.org/flavors/django-graphql-geojson

.. |Codecov| image:: https://img.shields.io/codecov/c/github/flavors/django-graphql-geojson.svg
:target: https://codecov.io/gh/flavors/django-graphql-geojson

.. |Code Climate| image:: https://api.codeclimate.com/v1/badges/67dbb917ad4cf8c422a6/maintainability
:target: https://codeclimate.com/github/flavors/django-graphql-geojson