X-Git-Url: https://git.openstreetmap.org/rails.git/blobdiff_plain/69e0457dea4e64aade37f411c26e1434c63ede14..b03a3f8889d6f752881a24cd23e010a9ced89efc:/lib/osm.rb

diff --git a/lib/osm.rb b/lib/osm.rb
index 1941d6daf..dea48cc71 100644
--- a/lib/osm.rb
+++ b/lib/osm.rb
@@ -22,10 +22,11 @@ module OSM
       @clat = lat
       @clon = lon
       @degrees_per_pixel = degrees_per_pixel
+      @degrees_per_pixel = 0.0000000001 if @degrees_per_pixel < 0.0000000001
       @width = width
       @height = height
-      @dlon = width / 2 * degrees_per_pixel
-      @dlat = height / 2 * degrees_per_pixel  * cos(@clat * PI / 180)
+      @dlon = width / 2 * @degrees_per_pixel
+      @dlat = height / 2 * @degrees_per_pixel  * cos(@clat * PI / 180)
 
       @tx = xsheet(@clon - @dlon)
       @ty = ysheet(@clat - @dlat)
@@ -68,13 +69,13 @@ module OSM
     attr_reader :tracksegs
 
     def initialize(filename)
+      @filename = filename
+    end
+
+    def points
       @possible_points = 0
       @actual_points = 0
       @tracksegs = 0
-      @points = []
-
-      file = File.new(filename)
-      parser = REXML::Parsers::SAX2Parser.new( file )
 
       lat = -1
       lon = -1
@@ -84,6 +85,8 @@ module OSM
       gotele = false
       gotdate = false
 
+      parser = REXML::Parsers::SAX2Parser.new(File.new(@filename))
+
       parser.listen( :start_element,  %w{ trkpt }) do |uri,localname,qname,attributes| 
         lat = attributes['lat'].to_f
         lon = attributes['lon'].to_f
@@ -112,18 +115,15 @@ module OSM
           ele = '0' unless gotele
           if lat < 90 && lat > -90 && lon > -180 && lon < 180
             @actual_points += 1
-            @points.push(Hash['latitude' => lat,'longitude' => lon,'timestamp' => date,'altitude' => ele,'segment' => @tracksegs])
+            yield Hash['latitude' => lat, 'longitude' => lon, 'timestamp' => date, 'altitude' => ele, 'segment' => @tracksegs]
           end
         end
         gotlatlon = false
         gotele = false
         gotdate = false
       end
-      parser.parse
-    end
 
-    def points
-      @points.each { |p| yield p }
+      parser.parse
     end
 
     def get_picture(min_lat, min_lon, max_lat, max_lon, num_points)
@@ -197,7 +197,7 @@ module OSM
     end
 
     def get_icon(min_lat, min_lon, max_lat, max_lon)
-      puts "getting icon for bbox #{min_lat},#{min_lon} - #{max_lat},#{max_lon}"
+      #puts "getting icon for bbox #{min_lat},#{min_lon} - #{max_lat},#{max_lon}"
       width = 50
       height = 50
       rat= Math.cos( ((max_lat + min_lat)/2.0) /  180.0 * 3.141592)
@@ -240,6 +240,34 @@ module OSM
 
   end
 
+  class GreatCircle
+    include Math
+
+    # initialise with a base position
+    def initialize(lat, lon)
+      @lat = lat * PI / 180
+      @lon = lon * PI / 180
+    end
+
+    # get the distance from the base position to a given position
+    def distance(lat, lon)
+      lat = lat * PI / 180
+      lon = lon * PI / 180
+      return 6372.795 * 2 * asin(sqrt(sin((lat - @lat) / 2) ** 2 + cos(@lat) * cos(lat) * sin((lon - @lon)/2) ** 2))
+    end
+
+    # get the worst case bounds for a given radius from the base position
+    def bounds(radius)
+      latradius = 2 * asin(sqrt(sin(radius / 6372.795 / 2) ** 2))
+      lonradius = 2 * asin(sqrt(sin(radius / 6372.795 / 2) ** 2 / cos(@lat) ** 2))
+      minlat = (@lat - latradius) * 180 / PI
+      maxlat = (@lat + latradius) * 180 / PI
+      minlon = (@lon - lonradius) * 180 / PI
+      maxlon = (@lon + lonradius) * 180 / PI
+      return { :minlat => minlat, :maxlat => maxlat, :minlon => minlon, :maxlon => maxlon }
+    end
+  end
+
   class GeoRSS
     def initialize(feed_title='OpenStreetMap GPS Traces', feed_description='OpenStreetMap GPS Traces', feed_url='http://www.openstreetmap.org/traces/')
       @doc = XML::Document.new