From f7dec053589d8e2f83c28b8192552a7566b0eff0 Mon Sep 17 00:00:00 2001
From: Alex Reisner <alex@alexreisner.com>
Date: Thu, 24 Mar 2011 23:07:48 -0400
Subject: [PATCH] Rename method and move to Calculations module.
---
lib/geocoder/calculations.rb | 21 +++++++++++++++++++++
lib/geocoder/orms/active_record.rb | 18 ++----------------
2 files changed, 23 insertions(+), 16 deletions(-)
diff --git a/lib/geocoder/calculations.rb b/lib/geocoder/calculations.rb
index 0a9b553e..84f4e339 100644
--- a/lib/geocoder/calculations.rb
+++ b/lib/geocoder/calculations.rb
@@ -147,6 +147,27 @@ module Geocoder
to_degrees [lat, lon]
end
+ ##
+ # Returns coordinates of the lower-left and upper-right corners of a box
+ # with the given point at its center. The radius is the shortest distance
+ # from the center point to any side of the box (the length of each side
+ # is twice the radius).
+ #
+ # This is useful for finding corner points of a map viewport, or for
+ # roughly limiting the possible solutions in a geo-spatial search
+ # (ActiveRecord queries use it thusly).
+ #
+ def bounding_box(latitude, longitude, radius, options = {})
+ units = options[:units] || :mi
+ radius = radius.to_f
+ [
+ latitude - (radius / latitude_degree_distance(units)),
+ longitude - (radius / longitude_degree_distance(latitude, units)),
+ latitude + (radius / latitude_degree_distance(units)),
+ longitude + (radius / longitude_degree_distance(latitude, units))
+ ]
+ end
+
##
# Convert degrees to radians.
# If an array (or multiple arguments) is passed,
diff --git a/lib/geocoder/orms/active_record.rb b/lib/geocoder/orms/active_record.rb
index ad00e2d5..9dec1d4b 100644
--- a/lib/geocoder/orms/active_record.rb
+++ b/lib/geocoder/orms/active_record.rb
@@ -172,9 +172,10 @@ module Geocoder::Orm
def default_near_scope_options(latitude, longitude, radius, options)
lat_attr = geocoder_options[:latitude]
lon_attr = geocoder_options[:longitude]
+ b = Geocoder::Calculations.bounding_box(latitude, longitude, radius, options)
conditions = \
["#{lat_attr} BETWEEN ? AND ? AND #{lon_attr} BETWEEN ? AND ?"] +
- coordinate_bounds(latitude, longitude, radius)
+ [b[0], b[2], b[1], b[3]]
if obj = options[:exclude]
conditions[0] << " AND #{table_name}.id != ?"
conditions << obj.id
@@ -187,21 +188,6 @@ module Geocoder::Orm
:conditions => conditions
}
end
-
- ##
- # Get the rough high/low lat/long bounds for a geographic point and
- # radius. Returns an array: <tt>[lat_lo, lat_hi, lon_lo, lon_hi]</tt>.
- # Used to constrain search to a (radius x radius) square.
- #
- def coordinate_bounds(latitude, longitude, radius, units = :mi)
- radius = radius.to_f
- [
- latitude - (radius / Geocoder::Calculations.latitude_degree_distance(units)),
- latitude + (radius / Geocoder::Calculations.latitude_degree_distance(units)),
- longitude - (radius / Geocoder::Calculations.longitude_degree_distance(latitude, units)),
- longitude + (radius / Geocoder::Calculations.longitude_degree_distance(latitude, units))
- ]
- end
end
##
--
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