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@@ -3,11 +3,12 @@ class Post < ActiveRecord::Base |
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EARTH_RADIUS_METRES = 6378000 |
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def self.near(lat, lon, radius_metres) |
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def self.near(lat, lon, radius_metres, layer_id) |
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# Santize inputs. Is this necessary? |
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lat = lat.to_f |
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lon = lon.to_f |
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radius_metres = radius_metres.to_i |
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layer_id = layer_id.to_i |
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# Calculate distance using the Haversine formula |
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self.find_by_sql(<<-ENDQUERY |
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@@ -34,13 +35,31 @@ class Post < ActiveRecord::Base |
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ON p.feed_id = f.id |
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WHERE |
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( #{EARTH_RADIUS_METRES} |
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* acos( cos( radians('#{lat}') ) |
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* cos( radians( p.lat ) ) |
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* cos( radians( p.lon ) |
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- radians('#{lon}') ) |
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+ sin( radians('#{lat}') ) |
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* sin( radians( p.lat ) ) ) ) |
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p.id IN |
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( -- Subquery returns a list of post_ids for posts on this layer |
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SELECT p.id |
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FROM feeds_layers fl |
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INNER JOIN feeds f |
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ON fl.feed_id = f.id |
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INNER JOIN posts p |
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ON p.feed_id = f.id |
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WHERE fl.layer_id = #{layer_id} |
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) |
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AND |
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( |
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#{EARTH_RADIUS_METRES} |
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* acos( cos( radians('#{lat}') ) |
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* cos( radians( p.lat ) ) |
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* cos( radians( p.lon ) |
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- radians('#{lon}') ) |
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+ sin( radians('#{lat}') ) |
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* sin( radians( p.lat ) ) ) |
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) |
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<= #{radius_metres} |
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ORDER BY distance |
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