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Drop the score filter and instead limit result quantity in similar_features()

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Schuyler Erle 2011-08-28 10:11:44 +02:00
parent 863c49575f
commit 3563cc8135
1 changed files with 4 additions and 4 deletions
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8
gazetteer/places/models.py
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@ -14,7 +14,7 @@ class AuthorityRecord(models.Model):
class FeatureSearchManager(models.GeoManager): class FeatureSearchManager(models.GeoManager):
def set_threshold(self, threshold): def set_threshold(self, threshold):
"""Set the limit for trigram similarity matching.""" """Set the limit for trigram similarity matching."""
cursor = connection.cursor cursor = connection.cursor()
cursor.execute("""SELECT set_limit(%f)""" % threshold) cursor.execute("""SELECT set_limit(%f)""" % threshold)
def overlaps(self, (minx, miny, maxx, maxy), text=None, srid=4326): def overlaps(self, (minx, miny, maxx, maxy), text=None, srid=4326):
@ -69,7 +69,7 @@ class Feature(models.Model):
return '' return ''
time_end.short_description = "End Date" time_end.short_description = "End Date"
def similar_features(self, max_distance=15000, scale_factor=2000): def similar_features(self, max_distance=15000, scale_factor=2000, limit=20):
cursor = connection.cursor() cursor = connection.cursor()
name = unicode(self).replace("'", "''") # escape ' name = unicode(self).replace("'", "''") # escape '
cursor.execute(""" cursor.execute("""
@ -82,11 +82,11 @@ class Feature(models.Model):
WHERE geometry && st_buffer('%s', %f) WHERE geometry && st_buffer('%s', %f)
AND preferred_name %%%% '%s' AND preferred_name %%%% '%s'
AND id <> %d AND id <> %d
LIMIT %d
) AS whatever ) AS whatever
WHERE %f * similarity / (distance + 1.0) >= 1.0
ORDER BY similarity / (distance + 1.0) DESC""" ORDER BY similarity / (distance + 1.0) DESC"""
% (scale_factor, name, self.geometry.wkt, self.geometry.wkt, % (scale_factor, name, self.geometry.wkt, self.geometry.wkt,
max_distance*0.00001, name, self.id, scale_factor) max_distance*0.00001, name, self.id, limit)
) )
result_list = [] result_list = []
fields = ('id', 'url', 'preferred_name', 'feature_type_id', 'admin1', 'admin2', 'is_primary') fields = ('id', 'url', 'preferred_name', 'feature_type_id', 'admin1', 'admin2', 'is_primary')