diff --git a/clean b/clean
old mode 100644
new mode 100755
diff --git a/quadkey/.__init__.py.swp b/quadkey/.__init__.py.swp
new file mode 100644
index 0000000..42a9598
Binary files /dev/null and b/quadkey/.__init__.py.swp differ
diff --git a/quadkey/__init__.py b/quadkey/__init__.py
index abe4fb5..bb07777 100644
--- a/quadkey/__init__.py
+++ b/quadkey/__init__.py
@@ -3,11 +3,10 @@
 
 class QuadKey:
 
-	def __init__(self, lat, lon, level):
+	def __init__(self, geo, level):
 		# assert lat, lon and level are valid
-		self.key = QuadKey.get_quadkey(lat, lon, level)
-		self.lat = lat
-		self.lon = lon
+		self.key = QuadKey.get_quadkey(geo, level)
+		self.geo = geo
 		self.level = level
 
 	def __str__(self):
@@ -19,12 +18,16 @@ def __repr__(self):
 	@classmethod
 	def from_str(cls, key):
 		level = len(key)
-		lat, lon = QuadKey.get_coordinates(key)
-		return cls(lat, lon, level)
+		geo = QuadKey.get_coordinates(key)
+		return cls(geo, level)
 
 	@staticmethod
-	def get_quadkey(lat, lon, level):	
-		pass
+	def get_quadkey(geo, level):	
+		pixel = TileSystem.geo_to_pixel(geo, level)
+		tile = TileSystem.pixel_to_tile(pixel)
+		quadkey = TileSystem.tile_to_quadkey(tile, level)
+		print geo, pixel, tile, quadkey
+		return quadkey
 
 	@staticmethod
 	def get_coordinates(key):
diff --git a/quadkey/tile_system.py b/quadkey/tile_system.py
index 4d7719b..2491eb4 100644
--- a/quadkey/tile_system.py
+++ b/quadkey/tile_system.py
@@ -1,5 +1,5 @@
 from util import precondition
-from math import cos, pi
+from math import sin, cos, atan, exp, log, pi
 
 def valid_level(level):
 	LEVEL_RANGE = (1,23)
@@ -9,7 +9,6 @@ class TileSystem:
 	"""
 	Class with static method to build quadkeys from lat, lon, levels
 	see http://msdn.microsoft.com/en-us/library/bb259689.aspx
-
 	"""
 
 	EARTH_RADIUS = 6378137
@@ -41,3 +40,65 @@ def map_scale(lat, level, dpi):
 		"""Gets the scale of the map expressed as ratio 1	: N. Returns N"""
 		return TileSystem.ground_resolution(lat, level) * dpi / 0.0254
 
+	@staticmethod
+	@precondition(lambda geo, lvl: valid_level(lvl))
+	def geo_to_pixel(geo, level):
+		"""Transform from geo coordinates to pixel coordinates"""
+		lat, lon = geo
+		lat = TileSystem.clip(lat, TileSystem.LATITUDE_RANGE)
+		lon = TileSystem.clip(lon, TileSystem.LONGITUDE_RANGE)
+		x = (lon + 180) / 360
+		sin_lat = sin(lat * pi / 180)
+		y = 0.5 - log((1 + sin_lat) / (1 - sin_lat) / (4 * pi))
+		# might need to cast to uint
+		map_size = TileSystem.map_size(level)
+		pixel_x = int(TileSystem.clip(x * map_size + 0.5, (0, map_size - 1)))
+		pixel_y = int(TileSystem.clip(y * map_size + 0.5, (0, map_size - 1)))
+		return pixel_x, pixel_y
+
+	@staticmethod
+	@precondition(lambda pix, lvl: valid_level(lvl))
+	def pixel_to_geo(pixel, level):
+		"""Transform from pixel to geo coordinates"""
+		pixel_x = pixel[0]
+		pixel_y = pixel[1]
+		map_size = float(TileSystem.map_size(level))
+		x = (TileSystem.clip(pixel_x, (0, map_size - 1)) / map_size) - 0.5
+		y = 0.5 - ( TileSystem.clip(pixel_y, (0, map_size - 1)) / map_size)
+		lat = 90 - 360 * atan(exp(-y * 2 * pi)) / pi
+		lon = 360 * x
+		return lat, lon
+
+	@staticmethod
+	def pixel_to_tile(pixel):
+		"""Transform pixel to tile coordinates"""
+		return pixel[0] / 256, pixel[1] / 256
+
+	@staticmethod
+	def tile_to_pixel(tile):
+		"""Transform tile to pixel coordinates"""
+		return tile[0] * 256, tile[1] * 256
+
+	@staticmethod
+	@precondition(lambda tile, lvl: valid_level(lvl))
+	def tile_to_quadkey(tile, level):
+		"""Transform tile coordinates to a quadkey"""
+		tile_x = tile[0]
+		tile_y = tile[1]
+		quadkey = ""
+		for i in xrange(level):
+			bit = level - i
+			digit = ord('0')
+			mask = 1 << (bit - 1) #if (bit - 1) > 0 else 1 >> (bit - 1)
+			if (tile_x & mask) is not 0:
+				digit += 1
+			if (tile_y & mask) is not 0:
+				digit += 2
+			quadkey += chr(digit)
+		return quadkey
+
+	@staticmethod
+	def quadkey_to_tile(quadkey):
+		"""Transform quadkey to tile coordinates"""
+		pass
+	
diff --git a/tests/quadkey_tests.py b/tests/quadkey_tests.py
index 3aa5970..895d703 100644
--- a/tests/quadkey_tests.py
+++ b/tests/quadkey_tests.py
@@ -14,7 +14,10 @@ def testToString(self):
 		pass
 
 	def testGetQuadKey(self):
-		pass
+		geo = (40, -105)
+		level = 9
+		key = '023101012'
+		self.assertEqual(key, QuadKey.get_quadkey(geo, level))
 
 	def testGetCoordinates(self):
 		pass
diff --git a/tests/tile_system.py b/tests/tile_system.py
index fd02aa1..527e928 100644
--- a/tests/tile_system.py
+++ b/tests/tile_system.py
@@ -24,19 +24,28 @@ def testMapScale(self):
 		TileSystem.map_scale(45, 7, 45)
 
 	def testGeoToPixel(self):
+		geo = (-105, 45)
+		level = 7
 		TileSystem.geo_to_pixel(geo, level)
 
 	def testPixelToGeo(self):
+		pixel = (50, 45)
+		level = 7
 		TileSystem.pixel_to_geo(pixel, level)
 
 	def testPixelToTile(self):
+		pixel = (50, 45)
 		TileSystem.pixel_to_tile(pixel)
 
 	def testTileToPixel(self):
+		tile = (3,3)
 		TileSystem.tile_to_pixel(tile)
 
 	def testTileToQuadkey(self):
+		tile = (3,3)
+		level = 7
 		TileSystem.tile_to_quadkey(tile, level)
 
 	def testQuadkeyToTile(self):
+		quadkey = '00'
 		TileSystem.quadkey_to_tile(quadkey)