From b0c34cf85ebdf408f661d958ff133c1a65623632 Mon Sep 17 00:00:00 2001
From: Alex Reisner <alex@alexreisner.com>
Date: Wed, 4 Nov 2009 00:06:38 -0500
Subject: [PATCH] When calculating geographic center, convert from degrees to
radians before computation, then back again before returning.
---
lib/geocoder.rb | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/lib/geocoder.rb b/lib/geocoder.rb
index 917a2ad2..1ac7fd9e 100644
--- a/lib/geocoder.rb
+++ b/lib/geocoder.rb
@@ -220,6 +220,9 @@ module Geocoder
#
def self.geographic_center(points)
+ # convert lat, lon pairs to radians
+ points.map!{ |p| [to_radians(p[0]), to_radians(p[1])] }
+
# convert to Cartesian coordinates
x = []; y = []; z = []
points.each do |p|
@@ -235,10 +238,11 @@ module Geocoder
# convert back to latitude/longitude
lon = Math.atan2(ya, xa)
- hyp = Math.sqrt(xa * xa + ya * ya)
+ hyp = Math.sqrt(xa**2 + ya**2)
lat = Math.atan2(za, hyp)
- [lat,lon]
+ # return answer in degrees
+ [to_degrees(lat), to_degrees(lon)]
end
##
@@ -248,6 +252,13 @@ module Geocoder
degrees * (Math::PI / 180)
end
+ ##
+ # Convert radians to degrees.
+ #
+ def self.to_degrees(radians)
+ (radians * 180.0) / Math::PI
+ end
+
##
# Query Google for geographic information about the given phrase.
#
--
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