1 // Copyright 2014 Google Inc. All rights reserved. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 /* 16 Package s2 is a library for working with geometry in S² (spherical geometry). 17 18 Its related packages, parallel to this one, are s1 (operates on S¹), r1 (operates on ℝ¹), 19 r2 (operates on ℝ²) and r3 (operates on ℝ³). 20 21 This package provides types and functions for the S2 cell hierarchy and coordinate systems. 22 The S2 cell hierarchy is a hierarchical decomposition of the surface of a unit sphere (S²) 23 into “cells”; it is highly efficient, scales from continental size to under 1 cm² 24 and preserves spatial locality (nearby cells have close IDs). 25 26 More information including an in-depth introduction to S2 can be found on the 27 S2 website https://s2geometry.io/ 28 */ 29 package s2 30