django - GeoDjango 从 json 或点保存数据

Question

如果我已经在文件(作为列表)或内存中或以 json 格式存在现有的 MultiString 坐标， 如何重写保存函数来保存这些点，而不是用户在 map 上创建对象？或者更准确地说，我如何将这些点加载到模型和数据库中？

内存/文件中的坐标

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

模型.py

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

如何使用坐标并将其保存在 geom 字段中？

Answer 1

使用 GEOS API 中的 LineString 和 MultiLineString 类在内存中创建线和多线，并将它们分配给模型的字段:

>>> 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()

使用 Django 2.0 和 PostGIS 进行测试。