Move common support code from the base migration to a library file where

[rails.git] / lib / osm.rb

diff --git a/lib/osm.rb b/lib/osm.rb
index 9e2ab04ada1cc752c39f739d5763a40a5d7b271a..dea48cc715f84d5b99b353e48caffd88d752ce92 100644 (file)
--- 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)
@@ -69,23 +70,23 @@ module OSM
 
     def initialize(filename)
       @filename = filename
-      @possible_points = 0
-      @actual_points = 0
-      @tracksegs = 0
     end
 
     def points
-      file = File.new(@filename)
-      parser = REXML::Parsers::SAX2Parser.new( file )
+      @possible_points = 0
+      @actual_points = 0
+      @tracksegs = 0
 
       lat = -1
       lon = -1
       ele = -1
-      date = Time.now();
+      date = DateTime.now();
       gotlatlon = false
       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
@@ -100,7 +101,7 @@ module OSM
 
       parser.listen( :characters, %w{ time } ) do |text|
         if text && text != ''
-          date = Time.parse(text)
+          date = DateTime.parse(text)
           gotdate = true
         end
       end
@@ -114,13 +115,14 @@ module OSM
           ele = '0' unless gotele
           if lat < 90 && lat > -90 && lon > -180 && lon < 180
             @actual_points += 1
-            yield 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
 
@@ -195,7 +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)
@@ -238,8 +240,36 @@ 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(description='OpenStreetMap GPS Traces')
+    def initialize(feed_title='OpenStreetMap GPS Traces', feed_description='OpenStreetMap GPS Traces', feed_url='http://www.openstreetmap.org/traces/')
       @doc = XML::Document.new
       @doc.encoding = 'UTF-8' 
       
@@ -250,14 +280,14 @@ module OSM
       @channel = XML::Node.new 'channel'
       rss << @channel
       title = XML::Node.new 'title'
-      title <<  'OpenStreetMap GPS Traces'
+      title <<  feed_title
       @channel << title
       description_el = XML::Node.new 'description'
       @channel << description_el
 
-      description_el << description
+      description_el << feed_description
       link = XML::Node.new 'link'
-      link << 'http://www.openstreetmap.org/traces/'
+      link << feed_url
       @channel << link
       image = XML::Node.new 'image'
       @channel << image
@@ -274,11 +304,11 @@ module OSM
       height << '100'
       image << height
       link = XML::Node.new 'link'
-      link << 'http://www.openstreetmap.org/traces/'
+      link << feed_url
       image << link
     end
 
-    def add(latitude=0, longitude=0, title_text='dummy title', url='http://www.example.com/', description_text='dummy description', timestamp=Time.now)
+    def add(latitude=0, longitude=0, title_text='dummy title', url='http://www.example.com/', description_text='dummy description', timestamp=DateTime.now)
       item = XML::Node.new 'item'
 
       title = XML::Node.new 'title'
@@ -288,21 +318,29 @@ module OSM
       link << url
       item << link
 
+      guid = XML::Node.new 'guid'
+      guid << url
+      item << guid
+
       description = XML::Node.new 'description'
       description << description_text
       item << description
 
       pubDate = XML::Node.new 'pubDate'
-      pubDate << timestamp.xmlschema
+      pubDate << timestamp.to_s(:rfc822)
       item << pubDate
 
-      lat_el = XML::Node.new 'geo:lat'
-      lat_el << latitude.to_s
-      item << lat_el
+      if latitude
+        lat_el = XML::Node.new 'geo:lat'
+        lat_el << latitude.to_s
+        item << lat_el
+      end
 
-      lon_el = XML::Node.new 'geo:lon'
-      lon_el << longitude.to_s
-      item << lon_el
+      if longitude
+        lon_el = XML::Node.new 'geo:long'
+        lon_el << longitude.to_s
+        item << lon_el
+      end
 
       @channel << item
     end