django-geofield 0.0.2

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
-----------

0. Install django-geofield

pip install django-geofield

1. Define GeoPositionField in your Model like this::

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

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

3. 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'

4. 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.

5. 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 .


6. 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](http://en.wikipedia.org/wiki/Geohash)




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](https://github.com/hkwi/python-geohash/blob/master/geohash.py)

License
------

MIT