Django-GeoField

A lightweight Django Geo Field to save and handle Geo Points. It supports to search the nearby points by their geohash.

Quick start

1. Install django-geofield

   pip install django-geofield

2. Add "django-geofield" to your INSTALLED_APPS setting like this::

   INSTALLED_APPS = (
       ...
       'django-geofield',
   )
   

3. Define GeoPositionField in your Model like this::

   class Point(models.Model):
       ...
       position = GeoPositionField(db_index=True)
   

4. Run python manage.py makemigrations and python manage.py migrate to make it effect

5. The field will save a geo point with a string into database like this :

   Point.objects.create(
                   position=GeoPosition(lat, lon, precision=6))
   
   'wtmm7w,30.49145747305400533377905958332121372222900390625,120.042387425481223317547119222581386566162109375'
   

6. If you want to query the points whose geohash is matched exactly with the given point , you can :

   pos = Point.objects.get(id=1)
   
   points_matched = Point.objects.filter(position__geoprecise=pos.position.geohash)
   

   The '__geoprecise' lookup will find all points have the same geohash.

7. If you want to query the points in expand area to eliminate the geohash's marginal error, you can :

   pos = Point.objects.get(id=1)
   
   points_matched = Point.objects.filter(position__geosearch=pos.position.geohash)
   

   The '__geosearch' lookup will find all points have one of 9 ( 1 center point and 8 expand point) geohash .

8. If you want to query the points within a specific range , you should lookup the geohash table to get the geohash length you want, then just search the cropped length.

   pos = Point.objects.get(id=1)
   
   points_matched = Point.objects.filter(position__geosearch=pos.position.geohash[0:4])
   

   

PS:

If you want to limit the distance strictly, you should writer your own codes to filter the result .

About GeoHash

Wikipedia

Support

python:

• "2.7"
• "3.2"
• "3.3"
• "3.4"
• "3.5"
• "3.5-dev" # 3.5 development branch
• "nightly" # currently points to 3.6-dev

Thanks

python-geohash

License

MIT