io_import_dxf/transverse_mercator.py

   1 # SPDX-FileCopyrightText: 2014-2022 Blender Foundation
   2 #
   3 # SPDX-License-Identifier: GPL-2.0-or-later
   4
   5 from math import sin, cos, atan, atanh, radians, tan, sinh, asin, cosh, degrees
   6
   7 # see conversion formulas at
   8 # http://en.wikipedia.org/wiki/Transverse_Mercator_projection
   9 # http://mathworld.wolfram.com/MercatorProjection.html
  10
  11
  12 class TransverseMercator:
  13     radius = 6378137
  14
  15     def __init__(self, lat=0, lon=0):
  16         self.lat = lat  # in degrees
  17         self.lon = lon  # in degrees
  18         self.lat_rad = radians(self.lat)
  19         self.lon_rad = radians(self.lon)
  20
  21     def fromGeographic(self, lat, lon):
  22         lat_rad = radians(lat)
  23         lon_rad = radians(lon)
  24         B = cos(lat_rad) * sin(lon_rad - self.lon_rad)
  25         x = self.radius * atanh(B)
  26         y = self.radius * (atan(tan(lat_rad) / cos(lon_rad - self.lon_rad)) - self.lat_rad)
  27         return x, y
  28
  29     def toGeographic(self, x, y):
  30         x /= self.radius
  31         y /= self.radius
  32         D = y + self.lat_rad
  33         lon = atan(sinh(x) / cos(D))
  34         lat = asin(sin(D) / cosh(x))
  35
  36         lon = self.lon + degrees(lon)
  37         lat = degrees(lat)
  38         return lat, lon