1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133 | from django import forms
from django.contrib.gis.gdal import GDALException
from django.contrib.gis.geos import GEOSException, GEOSGeometry
from django.core.exceptions import ValidationError
from django.utils.translation import gettext_lazy as _
from .widgets import OpenLayersWidget
class GeometryField(forms.Field):
"""
This is the basic form field for a Geometry. Any textual input that is
accepted by GEOSGeometry is accepted by this form. By default,
this includes WKT, HEXEWKB, WKB (in a buffer), and GeoJSON.
"""
widget = OpenLayersWidget
geom_type = 'GEOMETRY'
default_error_messages = {
'required': _('No geometry value provided.'),
'invalid_geom': _('Invalid geometry value.'),
'invalid_geom_type': _('Invalid geometry type.'),
'transform_error': _('An error occurred when transforming the geometry '
'to the SRID of the geometry form field.'),
}
def __init__(self, *, srid=None, geom_type=None, **kwargs):
self.srid = srid
if geom_type is not None:
self.geom_type = geom_type
super().__init__(**kwargs)
self.widget.attrs['geom_type'] = self.geom_type
def to_python(self, value):
"""Transform the value to a Geometry object."""
if value in self.empty_values:
return None
if not isinstance(value, GEOSGeometry):
if hasattr(self.widget, 'deserialize'):
try:
value = self.widget.deserialize(value)
except GDALException:
value = None
else:
try:
value = GEOSGeometry(value)
except (GEOSException, ValueError, TypeError):
value = None
if value is None:
raise ValidationError(self.error_messages['invalid_geom'], code='invalid_geom')
# Try to set the srid
if not value.srid:
try:
value.srid = self.widget.map_srid
except AttributeError:
if self.srid:
value.srid = self.srid
return value
def clean(self, value):
"""
Validate that the input value can be converted to a Geometry object
and return it. Raise a ValidationError if the value cannot be
instantiated as a Geometry.
"""
geom = super().clean(value)
if geom is None:
return geom
# Ensuring that the geometry is of the correct type (indicated
# using the OGC string label).
if str(geom.geom_type).upper() != self.geom_type and self.geom_type != 'GEOMETRY':
raise ValidationError(self.error_messages['invalid_geom_type'], code='invalid_geom_type')
# Transforming the geometry if the SRID was set.
if self.srid and self.srid != -1 and self.srid != geom.srid:
try:
geom.transform(self.srid)
except GEOSException:
raise ValidationError(
self.error_messages['transform_error'], code='transform_error')
return geom
def has_changed(self, initial, data):
""" Compare geographic value of data with its initial value. """
try:
data = self.to_python(data)
initial = self.to_python(initial)
except ValidationError:
return True
# Only do a geographic comparison if both values are available
if initial and data:
data.transform(initial.srid)
# If the initial value was not added by the browser, the geometry
# provided may be slightly different, the first time it is saved.
# The comparison is done with a very low tolerance.
return not initial.equals_exact(data, tolerance=0.000001)
else:
# Check for change of state of existence
return bool(initial) != bool(data)
class GeometryCollectionField(GeometryField):
geom_type = 'GEOMETRYCOLLECTION'
class PointField(GeometryField):
geom_type = 'POINT'
class MultiPointField(GeometryField):
geom_type = 'MULTIPOINT'
class LineStringField(GeometryField):
geom_type = 'LINESTRING'
class MultiLineStringField(GeometryField):
geom_type = 'MULTILINESTRING'
class PolygonField(GeometryField):
geom_type = 'POLYGON'
class MultiPolygonField(GeometryField):
geom_type = 'MULTIPOLYGON'
|