Clarify area equality definition in documentation.

pyresample/geometry.py

@@ -1,7 +1,4 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-#
-# Copyright (C) 2010-2023 Pyresample developers
+# Copyright (C) 2010-2025 Pyresample developers
 #
 # This program is free software: you can redistribute it and/or modify it under
 # the terms of the GNU Lesser General Public License as published by the Free
@@ -143,7 +140,13 @@ def update_hash(self, existing_hash: Optional[hashlib._Hash] = None) -> hashlib.
         return existing_hash
 
     def __eq__(self, other):
-        """Test for approximate equality."""
+        """Test for approximate equality.
+
+        Equality considers only the projection coordinates, not metadata such
+        as description or projection ID.  In other words, areas are considered
+        equal if they produce approximately the same output when used for
+        resampling, within floating point tolerances.
+        """
         if self is other:
             return True
         if not isinstance(other, BaseDefinition):
@@ -186,7 +189,7 @@ def _extract_lonlat_subarrays(
         return lons, lats
 
     def __ne__(self, other):
-        """Test for approximate equality."""
+        """Test for approximate inequality."""
         return not self.__eq__(other)
 
     def get_area_extent_for_subset(self, row_LR, col_LR, row_UL, col_UL):
@@ -2109,7 +2112,12 @@ def create_areas_def_legacy(self):
         return area_def_str
 
     def __eq__(self, other):
-        """Test for equality."""
+        """Test for equality.
+
+        Equality considers only the projection coordinates, not metadata such
+        as description or projection ID.  In other words, areas are considered
+        equal if they produce the same output when used for resampling.
+        """
         try:
             return ((np.allclose(self.area_extent, other.area_extent)) and
                     (self.crs == other.crs) and
@@ -2118,7 +2126,7 @@ def __eq__(self, other):
             return super().__eq__(other)
 
     def __ne__(self, other):
-        """Test for equality."""
+        """Test for inequality."""
         return not self.__eq__(other)
 
     def update_hash(self, existing_hash: Optional[hashlib._Hash] = None) -> hashlib._Hash: