def extent(self, identifiers=None):
"""Calculate extent using ogr GetExtent function
"""
layer = mapnik.Layer(self.layer_name, detect_prj(self.prj))
layer.datasource = mapnik.Shapefile(
file=self.layer_filename)
ds = osgeo.ogr.Open(self.layer_filename)
lyr = ds.GetLayer()
lyr.ResetReading()
w, e, s, n = lyr.GetExtent()
w, s = transform(
Proj(detect_prj(self.prj)), google_projection, w, s)
e, n = transform(
Proj(detect_prj(self.prj)), google_projection, e, n)
return {
'north': n,
'west': w,
'south': s,
'east': e}
def layer(self, layer_ids=None, request=None):
"""Return layer and styles for a shapefile.
http://127.0.0.1:8000/map/workspace/1/wms/?LAYERS=basic&SERVICE=
WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%
2Fvnd.ogc.se_inimage&FORMAT=image%2Fjpeg&SRS=EPSG%3A900913&BBOX=
523838.00391791,6818214.5267836,575010.91942212,6869720.7532931&
WIDTH=140&HEIGHT=140
"""
layers = []
styles = {}
layer = mapnik.Layer(self.layer_name, detect_prj(self.prj))
# TODO: ^^^ translation!
logging.debug("Giving shapefile %s to a mapnik layer...",
self.layer_filename)
layer.datasource = mapnik.Shapefile(
file=self.layer_filename)
if self.legend_id is not None:
legend = self._legend_object
style = legend.mapnik_style(
value_field=str(self.value_field))
else:
# Show layer with default legend.
style = self._default_mapnik_style()
style_name = str('Area style %s::%s::%s' % (
self.layer_filename,
self.legend_id,
self.value_field))
styles[style_name] = style
layer.styles.append(style_name)
layers = [layer]
logging.debug("Giving shapefile %s as layer to mapnik...",
self.layer_filename)
return layers, styles
def search(self, x, y, radius=None):
"""
Search area, line or point.
Make sure that value_field, search_property_id,
search_property_name are valid columns in your shapefile.
x,y are google coordinates
Note: due to mapnik #503 (http://trac.mapnik.org/ticket/503)
the search does not work for lines and points. So the
implementation was done with shapely.
"""
logger.debug("Searching coordinates (%0.2f, %0.2f) radius %r..." %
(x, y, radius))
if not self.search_property_name:
# We don't have anything to return, so don't search.
return []
if radius is not None:
# Manually make radius smaller
# RG, way later: it used to say 0.2 on the line below, but
# there were complaints saying that this was too
# small. From some manual testing, 1 (the default) is too
# large. I'll put 0.8. Obviously a very well argued value.
logger.debug("Adjusting radius...")
radius = radius * 0.8
transformed_x, transformed_y = transform(
google_projection, Proj(detect_prj(self.prj)), x, y)
query_point = Point(transformed_x, transformed_y)
ds = osgeo.ogr.Open(self.layer_filename)
try:
lyr = ds.GetLayer()
except AttributeError:
# #3033
# This one occurs when the file does not exist.
logger.error("The search function crashed. Probably due "
"to a missing shapefile.")
return []
if radius is not None:
# The radius needs to be transformed as well, but how?
# A transformed square will no longer be a square!
# This needs further attention...
transformed_x_radius, transformed_y_radius = transform(
google_projection, Proj(detect_prj(self.prj)),
x + radius, y + radius)
radius = max(abs(transformed_x - transformed_x_radius),
abs(transformed_y - transformed_y_radius))
lyr.SetSpatialFilterRect(
transformed_x - radius,
transformed_y - radius,
transformed_x + radius,
transformed_y + radius)
lyr.ResetReading()
feat = lyr.GetNextFeature()
results = []
while feat is not None:
geom = feat.GetGeometryRef()
if geom:
item = loads(geom.ExportToWkt())
distance = query_point.distance(item)
feat_items = feat.items()
if not radius or (radius is not None and distance < radius):
# Add stripped keys, because column names can contain
# spaces after the 'real' name.
for key in feat_items.keys():
feat_items[key.strip()] = feat_items[key]
# Found an item.
if self.search_property_name not in feat_items:
# This means that the search_property_name is not a
# valid field in the shapefile dbf.
logger.error(
('Search: The field "%s" cannot be found in '
'shapefile "%s". Available fields: %r'
'Check your settings in '
'lizard_shape.models.Shape.') %
(self.search_property_name, self.layer_name,
feat_items.keys()))
break # You don't have to search other rows.
name = str(feat_items[self.search_property_name])
if self.display_fields:
if self.display_fields[0]['field'] not in feat_items:
# This means that the value_field is not a
# valid field in the shapefile dbf.
logger.error(
('Search: The field "%s" cannot be found in '
'shapefile "%s". Check display_fields. '
'Options are: %s') %
(self.display_fields[0]['field'],
self.layer_name,
feat_items.keys()))
break # You don't have to search other rows.
name += ' - %s=%s' % (
self.display_fields[0]['name'],
str(float_to_string(feat_items[
self.display_fields[0]['field']])))
result = {'distance': distance,
'name': name,
'workspace_item': self.workspace_item}
try:
result.update(
{'google_coords':
transform(Proj(detect_prj(self.prj)),
google_projection,
*item.coords[0])})
except NotImplementedError:
logger.warning(
"Got a NotImplementedError while transforming "
"coordinates from %s to google with pyproj "
"for shapefile %s. Not returning google "
"coordinates.",
self.prj, self.shape)
if (self.search_property_id and
self.search_property_id in feat_items):
result.update(
{'identifier':
{'id': feat_items[self.search_property_id]}})
else:
logger.error("Problem with search_property_id: %s. "
"List of available properties: %r" %
(self.search_property_id,
feat_items.keys()))
results.append(result)
feat = lyr.GetNextFeature()
results = sorted(results, key=lambda a: a['distance'])
if len(results) > MAX_SEARCH_RESULTS:
logger.info('A lot of results found (%d), just taking top %s.',
len(results), MAX_SEARCH_RESULTS)
return results[:MAX_SEARCH_RESULTS]
