GeoHash 库

GeoHash

Geohash library for cplusplus.

GeoHash是空间索引的一种方式，特别适合点数据，而对线、面数据采用R树索引更有优势。

Basic Methods

#include <catch2/catch.hpp>
#include "cgeohash.hpp"

size_t precision = 12;
double longitude = 112.5584;
double latitude = 37.8324;
GeoHash::string_type geostr("ww8p1r4t8");
GeoHash::string_type geo_neighbor("dqcjq");

TEST_CASE("Test geohash encode & decode method") {

    SECTION("Test geohash encode method") {
        GeoHash::string_type out;
        GeoHash::encode(latitude, longitude, 9, out);
        REQUIRE(geostr == out);
    }
}

TEST_CASE("Test geohash decode method") {
    GeoHash::DecodedHash out = GeoHash::decode(geostr);
    //var diff = Math.abs(latitude - actual) < 0.0001
    REQUIRE(abs(latitude - out.latitude) <= out.latitude_err);
    REQUIRE(abs(longitude - out.longitude) <= out.longitude_err);
}

TEST_CASE("Test geohash neighbor method:finds neighbor to the north") {
    const int dir[2] = { 1,0 };
    GeoHash::string_type actual = GeoHash::neighbor(geo_neighbor, dir);
    GeoHash::string_type expected("dqcjw");
    REQUIRE(actual == expected);
}

TEST_CASE("Test geohash neighbor method:finds neighbor to the south-west") {
    const int dir[2] = { -1,-1 };
    GeoHash::string_type actual = GeoHash::neighbor(geo_neighbor, dir);
    GeoHash::string_type expected("dqcjj");
    REQUIRE(actual == expected);
}

TEST_CASE("Test decodes string to bounded box") {

    GeoHash::DecodedBBox box= GeoHash::decode_bbox(geostr);
    //[37.83236503601074,112.55836486816406,37.83240795135498,112.5584077835083];
    REQUIRE((latitude>=box.minlat && latitude <= box.maxlat));
    REQUIRE((longitude>=box.minlon && longitude<=box.maxlon));
}

Reference

1. https://github.com/sunng87/node-geohash.git
2. https://github.com/gnagel/node-geohash-cpp.git
3. https://codechina.csdn.net/mrbaolong/geohash.git