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⚡️ Speed up method GlobalMercator.MetersToTile by 6% #16

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⚡️ Speed up method GlobalMercator.MetersToTile by 6% #16

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25 changes: 12 additions & 13 deletions opendm/tiles/gdal2tiles.py
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Original file line number Diff line number Diff line change
Expand Up @@ -204,12 +204,12 @@ class GlobalMercator(object):
"""

def __init__(self, tileSize=256):
"Initialize the TMS Global Mercator pyramid"
"""Initialize the TMS Global Mercator pyramid"""
self.tileSize = tileSize
self.initialResolution = 2 * math.pi * 6378137 / self.tileSize
self._tileSize_float = float(tileSize)
self.initialResolution = 2 * math.pi * 6378137 / tileSize
# 156543.03392804062 for tileSize 256 pixels
self.originShift = 2 * math.pi * 6378137 / 2.0
# 20037508.342789244

def LatLonToMeters(self, lat, lon):
"Converts given lat/lon in WGS84 Datum to XY in Spherical Mercator EPSG:3857"
Expand Down Expand Up @@ -238,18 +238,18 @@ def PixelsToMeters(self, px, py, zoom):
return mx, my

def MetersToPixels(self, mx, my, zoom):
"Converts EPSG:3857 to pyramid pixel coordinates in given zoom level"

"""Converts EPSG:3857 to pyramid pixel coordinates in given zoom level"""
res = self.Resolution(zoom)
px = (mx + self.originShift) / res
py = (my + self.originShift) / res
shift = self.originShift
px = (mx + shift) / res
py = (my + shift) / res
return px, py

def PixelsToTile(self, px, py):
"Returns a tile covering region in given pixel coordinates"

tx = int(math.ceil(px / float(self.tileSize)) - 1)
ty = int(math.ceil(py / float(self.tileSize)) - 1)
"""Returns a tile covering region in given pixel coordinates"""
tsf = self._tileSize_float
tx = int(math.ceil(px / tsf) - 1)
ty = int(math.ceil(py / tsf) - 1)
return tx, ty

def PixelsToRaster(self, px, py, zoom):
Expand All @@ -259,8 +259,7 @@ def PixelsToRaster(self, px, py, zoom):
return px, mapSize - py

def MetersToTile(self, mx, my, zoom):
"Returns tile for given mercator coordinates"

"""Returns tile for given mercator coordinates"""
px, py = self.MetersToPixels(mx, my, zoom)
return self.PixelsToTile(px, py)

Expand Down