isabella232 / geometry.hpp

C++ geometry types

geometry.hpp

Provides header-only, generic C++ interfaces for geometry types, geometry collections, and features.

• mapbox::geometry::point
• mapbox::geometry::multi_point
• mapbox::geometry::line_string
• mapbox::geometry::multi_line_string
• mapbox::geometry::polygon
• mapbox::geometry::multi_polygon
• mapbox::geometry::geometry_collection
• mapbox::feature::feature (experimental)

Design

These types are designed to be easy to parse and serialize to GeoJSON.

They should also be a robust and high performance container for data processing and conversion.

Goals

• Header-only
• Fast compile
• c++11/c++14 compatibility
• No external dependencies for usage of core types (point, line_string, etc)
• Minimal dependencies for usage of enclosing geometry type (mapbox::variant)
• Easily adaptable to boost::geometry

Usage

Using a single type directly (requires no external dependencies):

#include <mapbox/geometry/point.hpp>
#include <iostream>

using mapbox::geometry::point;

int main() {
    point<double> pt(1.0,0.0);
    std::clog << "x: " << pt.x << " y: " << pt.y << "\n";
}

Creating a geometry collection (depends on https://github.com/mapbox/variant):

#include <mapbox/geometry/geometry.hpp>
#include <mapbox/variant.hpp>
#include <iostream>

using mapbox::geometry::geometry_collection;
using mapbox::geometry::geometry;
using mapbox::geometry::point;

using point_type = point<double>;

struct printer
{
    printer() {}

    void operator()(point_type const& pt) const
    {
        std::clog << "x: " << pt.x << " y: " << pt.y << "\n";
    }

    template <typename T>
    void operator()(T const& g) const
    {
        std::clog << "encountered non-point geometry\n";
    }
};

int main() {
    geometry_collection<double> gc;
    gc.emplace_back(point_type(1.0,0.0));
    geometry<double> const& geom = gc.at(0);
    printer visitor;
    mapbox::util::apply_visitor(visitor,geom);
}