better vector functionality

lib/geo_magic/point.rb

@@ -57,15 +57,28 @@ def self.create_from *args
       new latitude, longitude
     end    
 
-    def move dlat, dlong
+    def move! dlat, dlong
       @latitude   += dlat
       @longitude  += dlong
+      self
+    end
+
+    def move dlat, dlong
+      cloned = self.dup
+      cloned.latitude   += dlat
+      cloned.longitude  += dlong
+      cloned
     end
 
     def move_vector vector
+      raise ArgumentError, "Argument must be a GeoMagic::Vector, was #{vector}" if !vector.kind_of? GeoMagic::Vector
       move vector.lat_distance, vector.long_distance
     end
 
+    def move_vector! vector
+      raise ArgumentError, "Argument must be a GeoMagic::Vector, was #{vector}" if !vector.kind_of? GeoMagic::Vector
+      move! vector.lat_distance, vector.long_distance
+    end
 
     def to_point_hash mode= :long
       case mode

lib/geo_magic/vector.rb

@@ -8,8 +8,8 @@ def initialize p0, p1
       @p1 = p1
     end
 
-    def create_at center, vector
-      new center, center.move(vector)
+    def self.create_at center, vector
+      new center, center.move_vector(vector)
     end
 
     def length type = nil
@@ -28,6 +28,14 @@ def length type = nil
       d
     end
 
+    def lat_distance
+      length(:latitude).in_radians
+    end
+
+    def long_distance
+      length(:longitude).in_radians
+    end
+
     def vector_distance
       GeoMagic::Distance::Vector.new length(:latitude), length(:longitude), :lat_factor => lat_factor
     end        

spec/geo_magic/vector_spec.rb

@@ -16,13 +16,42 @@
       end
     end
 
+    describe 'class methods' do
+      describe '#create_at' do
+        it "should create a vector from a point and another vector" do
+          v2 = GeoMagic::Vector.create_at @a, @vector
+          v2.should be_a(GeoMagic::Vector)
+        end
+      end
+    end
+
     describe '#distance' do
       it "is has a distance" do
         @vector.distance.should be_a(GeoMagic::Distance)
         @vector.distance.in_meters.should > 500
       end
     end
 
+    describe '#lat_factor' do
+      it "is has a lat_factor of 2" do
+        @vector.lat_factor.should >= 2
+      end
+    end    
+
+    describe '#length' do
+      describe ':latitude' do
+        it "is has a latitude length of ..." do
+          @vector.length(:latitude).in_km.should >= 0.5
+        end
+      end
+
+      describe ':longitude' do
+        it "is has a longitude length of ..." do
+          @vector.length(:longitude).in_km.should >= 0.5
+        end
+      end
+    end    
+
     describe '#vector_distance' do
       it "is has a vector_distance" do
         @vector.vector_distance.should be_a(GeoMagic::Distance::Vector)