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117 | import logging
from django.conf import settings
from django.contrib.gis import gdal
from django.contrib.gis.geometry import json_regex
from django.contrib.gis.geos import GEOSException, GEOSGeometry
from django.forms.widgets import Widget
from django.utils import translation
logger = logging.getLogger('django.contrib.gis')
class BaseGeometryWidget(Widget):
"""
The base class for rich geometry widgets.
Render a map using the WKT of the geometry.
"""
geom_type = 'GEOMETRY'
map_srid = 4326
map_width = 600
map_height = 400
display_raw = False
supports_3d = False
template_name = '' # set on subclasses
def __init__(self, attrs=None):
self.attrs = {}
for key in ('geom_type', 'map_srid', 'map_width', 'map_height', 'display_raw'):
self.attrs[key] = getattr(self, key)
if attrs:
self.attrs.update(attrs)
def serialize(self, value):
return value.wkt if value else ''
def deserialize(self, value):
try:
return GEOSGeometry(value)
except (GEOSException, ValueError, TypeError) as err:
logger.error("Error creating geometry from value '%s' (%s)", value, err)
return None
def get_context(self, name, value, attrs):
context = super().get_context(name, value, attrs)
# If a string reaches here (via a validation error on another
# field) then just reconstruct the Geometry.
if value and isinstance(value, str):
value = self.deserialize(value)
if value:
# Check that srid of value and map match
if value.srid and value.srid != self.map_srid:
try:
ogr = value.ogr
ogr.transform(self.map_srid)
value = ogr
except gdal.GDALException as err:
logger.error(
"Error transforming geometry from srid '%s' to srid '%s' (%s)",
value.srid, self.map_srid, err
)
context.update(self.build_attrs(self.attrs, {
'name': name,
'module': 'geodjango_%s' % name.replace('-', '_'), # JS-safe
'serialized': self.serialize(value),
'geom_type': gdal.OGRGeomType(self.attrs['geom_type']),
'STATIC_URL': settings.STATIC_URL,
'LANGUAGE_BIDI': translation.get_language_bidi(),
**(attrs or {}),
}))
return context
class OpenLayersWidget(BaseGeometryWidget):
template_name = 'gis/openlayers.html'
map_srid = 3857
class Media:
css = {
'all': (
'https://cdnjs.cloudflare.com/ajax/libs/ol3/4.6.5/ol.css',
'gis/css/ol3.css',
)
}
js = (
'https://cdnjs.cloudflare.com/ajax/libs/ol3/4.6.5/ol.js',
'gis/js/OLMapWidget.js',
)
def serialize(self, value):
return value.json if value else ''
def deserialize(self, value):
geom = super().deserialize(value)
# GeoJSON assumes WGS84 (4326). Use the map's SRID instead.
if geom and json_regex.match(value) and self.map_srid != 4326:
geom.srid = self.map_srid
return geom
class OSMWidget(OpenLayersWidget):
"""
An OpenLayers/OpenStreetMap-based widget.
"""
template_name = 'gis/openlayers-osm.html'
default_lon = 5
default_lat = 47
default_zoom = 12
def __init__(self, attrs=None):
super().__init__()
for key in ('default_lon', 'default_lat', 'default_zoom'):
self.attrs[key] = getattr(self, key)
if attrs:
self.attrs.update(attrs)
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