def wdpapoly2mpa():
wpolys = WdpaPolygon.objects.all().defer(*WdpaPolygon.get_geom_fields()).order_by("wdpaid")
count = 0
for wpoly in wpolys:
mpa, created = Mpa.objects.get_or_create(wdpa_id=wpoly.wdpaid)
count += 1
print count
mpa.name = wpoly.name
mpa.wdpa_id = wpoly.wdpaid
mpa.country = wpoly.country
mpa.sub_location = wpoly.sub_loc
mpa.designation = wpoly.desig
mpa.designation_eng = wpoly.desig_eng
mpa.designation_type = wpoly.desig_type
mpa.iucn_category = wpoly.iucn_cat
mpa.int_criteria = wpoly.int_crit
mpa.marine = wpoly.marine
mpa.status = wpoly.status
mpa.status_year = wpoly.status_yr
mpa.area_notes = wpoly.area_notes
mpa.rep_m_area = wpoly.rep_m_area
mpa.calc_m_area = wpoly.gis_m_area
mpa.rep_area = wpoly.rep_area
mpa.calc_area = wpoly.gis_area
mpa.gov_type = wpoly.gov_type
mpa.mgmt_auth = wpoly.mang_auth
mpa.mgmt_plan_ref = wpoly.mang_plan
# mpa.geom_smerc = wpoly.geom_smerc
# mpa.geom = wpoly.geom
# mpa.geog = wpoly.geog
mpa.save()
# SQL update all geometry rows, much faster than through django
print "UPDATE geometry columns"
cursor = connection.cursor()
cursor.execute("UPDATE mpa_mpa SET geog = w.geog FROM wdpa_wdpapolygon as w WHERE mpa_mpa.wdpa_id = w.wdpaid")
transaction.commit_unless_managed()
print "UPDATE complete"
Mpa.set_all_geom_from_geog()
def lookup_point(request):
"""Find nearby polygons with a point and search radius.
Three lookup methods are supported:
sphericalmercator: radius (in km) is applied to search buffer in
900913 (aka Google Spherical Mercator) projection. This method
is appropriate when used in conjuction with web maps.
greatcircle: uses PostGIS ST_DWithin spatial query on a geography
column, using great circle distances.
point: simple test if point is inside polygons (e.g., radius=0)
These methods assume the geometries are in a Geography column. Edge
cases across the dateline are handled correctly.
Different methods are needed if a regular Geometry column is used
in order to handle cases across the dateline."""
mpa_list = ()
default_method = 'webmercator'
try:
lon = float(request.GET['lon'])
lat = float(request.GET['lat'])
try:
radius = float(request.GET['radius'])
except:
radius = 225.0 # km
try:
method = request.GET['method'] or default_method # set default if empty string passed
except (KeyError):
method = default_method
if method not in ('point', 'greatcircle', 'webmercator', 'webmercator_buffer', 'webmercator_box', 'webmercator_simple'):
raise LookupMethodError('Unknown or malformed lookup method passed in GET query string.')
if (radius == 0):
method = 'point'
except:
# Bad input, return empty list
return render(request, 'wdpa/mpalookup.json', {
'mpa_list': mpa_list,
}, content_type='application/json; charset=utf-8')
else:
# We need to normalize the longitude into the range -180 to 180 so we don't
# make the cast to PostGIS Geography type complain
point = geos.Point(normalize_lon(lon), lat, srid=gdal.SpatialReference('WGS84').srid) # srid=4326 , WGS84 geographic
if (method == 'webmercator'):
if (normalize_lon(lon) < 0):
lon360 = normalize_lon(lon) + 360
else:
lon360 = normalize_lon(lon) - 360
point360 = geos.Point(lon360, lat, srid=gdal.SpatialReference('WGS84').srid)
point.transform(900913) # Google Spherical Mercator srid
point360.transform(900913)
#mpa_list = WdpaPolygon.objects.filter(geom_smerc__dwithin=(point, Distance(km=radius))).defer(*WdpaPolygon.get_geom_fields())
mpa_list = WdpaPolygon.objects.filter(Q(geom_smerc__dwithin=(point, Distance(km=radius))) | Q(geom_smerc__dwithin=(point360, Distance(km=radius)))).defer(*WdpaPolygon.get_geom_fields())
search = point
elif (method == 'webmercator_buffer'):
point.transform(900913) # Google Spherical Mercator srid
searchbuffer = point.buffer(radius * 1000) # convert km to m, create buffer
mpa_list = WdpaPolygon.objects.filter(geog__intersects=searchbuffer).defer(*WdpaPolygon.get_geom_fields())
search = searchbuffer
elif (method == 'webmercator_box'):
point.transform(900913) # Google Spherical Mercator srid
searchbuffer = point.buffer(radius * 1000)
mpa_list = WdpaPolygon.objects.filter(geog__intersects=searchbuffer.envelope).defer(*WdpaPolygon.get_geom_fields()) # use simple bounding box instead
search = searchbuffer.envelope
elif (method == 'webmercator_simple'):
point.transform(900913) # Google Spherical Mercator srid
searchbuffer = point.buffer(radius * 1000, quadsegs=2) # simple buffer with 2 segs per quarter circle
mpa_list = WdpaPolygon.objects.filter(geog__intersects=searchbuffer).defer(*WdpaPolygon.get_geom_fields())
search = searchbuffer
elif (method == 'greatcircle'):
mpa_list = WdpaPolygon.objects.filter(geog__dwithin=(point, Distance(km=radius))).defer(*WdpaPolygon.get_geom_fields())
search = point
elif (method == 'point'):
mpa_list = WdpaPolygon.objects.filter(geog__intersects=point).defer(*WdpaPolygon.get_geom_fields())
search = point
candidate_radius = radius * 2.2 # We're using big icons on a point, this let's us catch it better
mpa_candidate_list = MpaCandidate.objects.filter(geog__dwithin=(point, Distance(km=candidate_radius))).defer(*MpaCandidate.get_geom_fields())
search.transform(4326)
return render(request, 'wdpa/mpalookup.json', {
'search': search.coords,
'mpa_list': mpa_list,
'mpa_candidate_list': mpa_candidate_list,
}, content_type='application/json; charset=utf-8')