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ThomasG77/scales-and-zoom-levels.py

Created June 13, 2020 10:55
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Python functions to convert from/to zoom level to scale (assuming 96 dpi and latitude 0)
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scales-and-zoom-levels.py
from math import cos, log, pi
def getScale(zoom_level, screen_dpi=96, latitude=0):
resolution = (6378137.0 * 2 * pi / 256) * cos(latitude) / (2**zoom_level)
return (screen_dpi * 1/0.0254 * resolution)
def getZoomLevel(scale, screen_dpi=96, latitude=0):
resolution = scale / (screen_dpi * 1/0.0254)
zoom_level = ((6378137.0 * 2 * pi / 256) * cos(latitude)) / resolution
return log(zoom_level)/log(2)
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