cppGeoTile

C++ library to handle tiles and points of different projections, in particular WGS 84 (Latitude, Longitude), Spherical Mercator (Meters), Pixel Pyramid and Tiles (TMS, Google, QuadTree)

Usage

The library cppGeoTile consist of two main classes, namely Point and Tile. As already mentioned they allow you to convert various geo projections.

Point

Example of the class Point.

#include <GeoTile/point.hpp>

#include <iostream>

int main()
{
    // meters in Spherical Mercator EPSG:900913
    auto zoom = 19;
    auto meterX = -9757148.442088600;
    auto meterY = 5138517.444985110;

    auto point = Point::fromMeters(meterX, meterY);

    auto [pixelX, pixelY] = point.getPixels(zoom);
    std::cout << "PixelX: " << pixelX << "PixelY: " << pixelY << "\n";

    auto [lat, lon] = point.getLatLon();
    std::cout << "Latitude: " << lat << "Longitude: " << lon << "\n";
}

Tile

Example of the class Tile.

#include <GeoTile/tile.hpp>

#include <iostream>

int main()
{
    auto zoom = 19;
    auto tmsX = 134494;
    auto tmsY = 329369;

    auto tile = Tile::fromTms(tmsX, tmsY, zoom); // Tile Map Service (TMS) X Y and zoom

    std::cout << "QuadTree: " << tile.getQuadTree()<< "\n"; // QuadTree: 0302222310303211330
    std::cout << "Google: " << tile.getGoogle()<< "\n"; // Google:  (134494, 194918)
}

Building the Library

Note: all commands shown here are expected to be run in the source root of the library.

To configure the build environment, use either:

$ cmake -S . -B build

if you are using cmake >= 3.13, or:

$ mkdir build
$ cd build
$ cmake ..

if you are using cmake <= 3.12

Additional configuration options:

• -DCMAKE_BUILD_TYPE=Release to enable optimizations. (Default: Debug)
• -DENABLE_GEOTILETEST=OFF to disable building the tests. (Default ON)

Build: cmake --build build

Run tests: cmake --build build --target test

Note: Due to the idiosyncratic separation of 'test execution' from 'building' in CMake, you will have to run the library build before you can run the tests.

Notes

This repository is a C++ port of (my) pyGeoTile.

Further, it is inspired by:

• Tiles à la Google Maps: http://www.maptiler.org/google-maps-coordinates-tile-bounds-projection/
• Bing Maps Tile System: https://msdn.microsoft.com/en-us/library/bb259689.aspx
• Showing pixel and tile coordinates: https://developers.google.com/maps/documentation/javascript/examples/map-coordinates?hl=de
• Mercantile: https://github.com/mapbox/mercantile