CODEWITHSUNDEEP
djangogeodjango
Geoffrey Nyaga
Geoffrey Nyaga

Reputation: 93

GeoDjango save data from json or points

If I already have existing MultiString cordinates in a file(as a list) or memory or in a json format, How do I override the save function to save these points instead of the user creating the object on a map? Or perhaps more precisely, how do i load these points to a model and the database?

Coordinates in memory/file

[[36.66678428649903, -1.5474249907643578], [36.670904159545906, -1.542620219636788], [36.66635513305665,-1.5353272427374922],[36.662406921386726, -1.5403894293513378]]

models.py

class LogsUpload(models.Model):
    name = models.CharField(max_length=240)
    geom  = gis_models.MultiLineStringField(blank=True, null=True)

How do I use the cordinates and save them in the geom field?

Upvotes: 4

Views: 3336

Answers (2)

Satendra
Satendra

Reputation: 6865

Use PointField of gis.db for storing [lat, long] data.

from django.contrib.gis.db import models as gis_model

geom = gis_model.PointField(null=True, spatial_index=True, geography=True)

PointField accept GEOSGeometry object, so you can create your data like.

import json
from django.contrib.gis.geos import GEOSGeometry

data_coordinates = [[36.66678428649903, -1.5474249907643578], [36.670904159545906, -1.542620219636788], [36.66635513305665,-1.5353272427374922],[36.662406921386726, -1.5403894293513378]]

for coordinate in data_coordinates:
    point = {
        "type": "Point",
        "coordinates": coordinate 
    }
    
    LogsUpload.objects.create(name="your location name", geom=GEOSGeometry(json.dumps(point)))

Read more: Storing, querying & serializing location data with Django using PostGIS

UPDATE

If you want to save all of them in one object of LogsUpload model, you can simply use ArrayField or JSONField of django.db.models

Upvotes: 2

Udi
Udi

Reputation: 30532

Use LineString and MultiLineString classes from the GEOS API to create lines and multi-lines in memory, and assign them to your model's fields:

>>> from django.contrib.gis.geos import LineString, MultiLineString
>>> DATA = [[36.66678428649903, -1.5474249907643578], [36.670904159545906, -1.542620219636788], [36.66635513305665,-1.5353272427374922],[36.662406921386726, -1.5403894293513378]]
>>> line = LineString(DATA)
>>> line
<LineString object at 0x7f96538f49a0>
>>> line.length
0.02134446840090856
>>> line.geojson
'{ "type": "LineString", "coordinates": [ [ 36.666784286499031, -1.547424990764358 ], [ 36.670904159545906, -1.542620219636788 ], [ 36.666355133056648, -1.535327242737492 ], [ 36.662406921386726, -1.540389429351338 ] ] }'
>>> multi_line = MultiLineString(line)
>>> multi_line
<MultiLineString object at 0x7f96536ccbc0>
>>> multi_line[0]
<LineString object at 0x7f964187b3c8>
>>> multi_line.length
0.02134446840090856
>>> multi_line.geojson
'{ "type": "MultiLineString", "coordinates": [ [ [ 36.666784286499031, -1.547424990764358 ], [ 36.670904159545906, -1.542620219636788 ], [ 36.666355133056648, -1.535327242737492 ], [ 36.662406921386726, -1.540389429351338 ] ] ] }'

>>> from myapp.models import LogsUpload
>>> o = LogsUpload(name="foo", geom=multi_line)
>>> o.full_clean()
>>> o.save()

Tested with Django 2.0 and PostGIS.

Upvotes: 3

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