From 1c80e0c62534c43fce509a28d433b14e9bb2b2ec Mon Sep 17 00:00:00 2001
From: mozman <me@mozman.at>
Date: Wed, 6 Mar 2024 11:05:07 +0100
Subject: [PATCH] use wgs84 converter functions from ezdxf.math

---
 src/ezdxf/addons/geo.py | 50 +++++++++--------------------------------
 1 file changed, 10 insertions(+), 40 deletions(-)

diff --git a/src/ezdxf/addons/geo.py b/src/ezdxf/addons/geo.py
index edea1bd3d..edc5eaf39 100644
--- a/src/ezdxf/addons/geo.py
+++ b/src/ezdxf/addons/geo.py
@@ -1,4 +1,4 @@
-#  Copyright (c) 2020-2023, Manfred Moitzi
+#  Copyright (c) 2020-2024, Manfred Moitzi
 #  License: MIT License
 """
 Implementation of the `__geo_interface__`: https://gist.github.com/sgillies/2217756
@@ -28,7 +28,13 @@
 import copy
 import math
 import enum
-from ezdxf.math import Vec3, has_clockwise_orientation, Matrix44
+from ezdxf.math import (
+    Vec3,
+    has_clockwise_orientation,
+    Matrix44,
+    world_mercator_to_gps,
+    gps_to_world_mercator,
+)
 from ezdxf.path import make_path, from_hatch_boundary_path, make_polygon_structure
 from ezdxf.entities import DXFGraphic, LWPolyline, Point, Polyline, Line
 from ezdxf.entities.polygon import DXFPolygon
@@ -990,20 +996,7 @@ def wgs84_4326_to_3395(location: Vec3) -> Vec3:
             value (East-West) in decimal degrees and the y-attribute
             represents the latitude value (North-South) in decimal degrees.
     """
-    # From: https://epsg.io/4326
-    # EPSG:4326 WGS84 - World Geodetic System 1984, used in GPS
-    # To: https://epsg.io/3395
-    # EPSG:3395 - World Mercator
-    # Source: https://gis.stackexchange.com/questions/259121/transformation-functions-for-epsg3395-projection-vs-epsg3857
-    longitude = math.radians(location.x)  # east
-    latitude = math.radians(location.y)  # north
-    a = WGS84_SEMI_MAJOR_AXIS
-    e = WGS84_ELLIPSOID_ECCENTRIC
-    e_sin_lat = math.sin(latitude) * e
-    c = math.pow((1.0 - e_sin_lat) / (1.0 + e_sin_lat), e / 2.0)  # 7-7 p.44
-    y = a * math.log(math.tan(CONST_PI_4 + latitude / 2.0) * c)  # 7-7 p.44
-    x = a * longitude
-    return Vec3(x, y)
+    return Vec3(gps_to_world_mercator(location.x, location.y))
 
 
 def wgs84_3395_to_4326(location: Vec3, tol: float = 1e-6) -> Vec3:
@@ -1017,30 +1010,7 @@ def wgs84_3395_to_4326(location: Vec3, tol: float = 1e-6) -> Vec3:
         tol: accuracy for latitude calculation
 
     """
-    # From: https://epsg.io/3395
-    # EPSG:3395 - World Mercator
-    # To: https://epsg.io/4326
-    # EPSG:4326 WGS84 - World Geodetic System 1984, used in GPS
-    # Source: Map Projections - A Working Manual
-    # https://pubs.usgs.gov/pp/1395/report.pdf
-    a = WGS84_SEMI_MAJOR_AXIS
-    e = WGS84_ELLIPSOID_ECCENTRIC
-    e2 = e / 2.0
-    pi2 = CONST_PI_2
-    x, y, _ = location
-    t = math.e ** (-y / a)  # 7-10 p.44
-    latitude_ = pi2 - 2.0 * math.atan(t)  # 7-11 p.45
-    while True:
-        e_sin_lat = math.sin(latitude_) * e
-        latitude = pi2 - 2.0 * math.atan(
-            t * ((1.0 - e_sin_lat) / (1.0 + e_sin_lat)) ** e2
-        )  # 7-9 p.44
-        if abs(latitude - latitude_) < tol:
-            break
-        latitude_ = latitude
-
-    longitude = x / a  # 7-12 p.45
-    return Vec3(math.degrees(longitude), math.degrees(latitude))
+    return Vec3(world_mercator_to_gps(location.x, location.y, tol))
 
 
 def dms2dd(d: float, m: float = 0, s: float = 0) -> float: