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/*! \file */ | ||
#ifndef _GEOJSON_H | ||
#define _GEOJSON_H | ||
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/* | ||
GeoJSON writer for boost::geometry objects, using RapidJSON. | ||
This isn't core tilemaker functionality but helps with debugging. | ||
As yet it only outputs (Multi)Polygons but can be extended for more types. | ||
Example: | ||
auto gj = GeoJSON() | ||
gj.addGeometry(myMultiPolygon); | ||
gj.finalise(); | ||
std::cout << gj.toString() << std::endl; | ||
Or use gj.toFile("output.geojson") to write to file. | ||
Calling finalise(true) will 'unproject' Y values (i.e. latp2lat). | ||
Todo: support more geometries, set/write properties. | ||
*/ | ||
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#include <iostream> | ||
#include <math.h> | ||
#include "geom.h" | ||
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#include "rapidjson/document.h" | ||
#include "rapidjson/writer.h" | ||
#include "rapidjson/stringbuffer.h" | ||
#include "rapidjson/filewritestream.h" | ||
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typedef boost::variant<Point,Linestring,MultiLinestring,Polygon,MultiPolygon,Ring> AnyGeometry; | ||
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using namespace rapidjson; | ||
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struct GeoJSON { | ||
Document document; | ||
std::vector<AnyGeometry> geometries; | ||
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GeoJSON() { | ||
document.SetObject(); | ||
document.AddMember("type", Value().SetString("FeatureCollection"), document.GetAllocator()); | ||
} | ||
void addGeometry(AnyGeometry geom) { | ||
geometries.emplace_back(geom); | ||
} | ||
struct SerialiseGeometry { | ||
Value *obj; | ||
Document::AllocatorType *alloc; | ||
bool unproject; | ||
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SerialiseGeometry(Value *obj, Document::AllocatorType *alloc, bool unproject) : | ||
obj(obj), alloc(alloc), unproject(unproject) {} | ||
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double deg2rad(double deg) { return (M_PI/180.0) * deg; } | ||
double rad2deg(double rad) { return (180.0/M_PI) * rad; } | ||
double latp2lat(double latp) { return rad2deg(atan(exp(deg2rad(latp)))*2.0)-90.0; } | ||
Value ringToArray(Ring &r) { | ||
Value arr(kArrayType); | ||
for (auto &point : r) { | ||
Value pt(kArrayType); | ||
pt.PushBack(point.x(), *alloc); | ||
pt.PushBack(unproject ? latp2lat(point.y()) : point.y(), *alloc); | ||
arr.PushBack(pt, *alloc); | ||
} | ||
return arr; | ||
} | ||
void operator()(Point &p) {} // todo | ||
void operator()(Linestring &ls) {} // todo | ||
void operator()(MultiLinestring &mls) {} // todo | ||
void operator()(Ring &r) { | ||
Value coordinates(kArrayType); | ||
coordinates.PushBack(ringToArray(r), *alloc); | ||
obj->AddMember("coordinates", coordinates, *alloc); | ||
obj->AddMember("type", Value().SetString("Polygon"), *alloc); | ||
} | ||
void operator()(Polygon &p) { | ||
Value coordinates(kArrayType); | ||
coordinates.PushBack(ringToArray(p.outer()), *alloc); | ||
for (auto &inner : p.inners()) { | ||
coordinates.PushBack(ringToArray(inner), *alloc); | ||
} | ||
obj->AddMember("coordinates", coordinates, *alloc); | ||
obj->AddMember("type", Value().SetString("Polygon"), *alloc); | ||
} | ||
void operator()(MultiPolygon &mp) { | ||
Value coordinates(kArrayType); | ||
for (auto &polygon : mp) { | ||
Value polyCoords(kArrayType); | ||
polyCoords.PushBack(ringToArray(polygon.outer()), *alloc); | ||
for (auto &inner : polygon.inners()) { | ||
polyCoords.PushBack(ringToArray(inner), *alloc); | ||
} | ||
coordinates.PushBack(polyCoords, *alloc); | ||
} | ||
obj->AddMember("coordinates", coordinates, *alloc); | ||
obj->AddMember("type", Value().SetString("MultiPolygon"), *alloc); | ||
} | ||
}; | ||
void finalise(bool unproject = false) { | ||
Value features(kArrayType); | ||
for (AnyGeometry &g : geometries) { | ||
// type | ||
Value obj(kObjectType); | ||
obj.AddMember("type", Value().SetString("Feature"), document.GetAllocator()); | ||
// properties (todo) | ||
Value properties(kObjectType); | ||
obj.AddMember("properties", properties, document.GetAllocator()); | ||
// geometry | ||
Value geometry(kObjectType); | ||
boost::apply_visitor(SerialiseGeometry(&geometry, &(document.GetAllocator()), unproject), g); | ||
obj.AddMember("geometry", geometry, document.GetAllocator()); | ||
// add to list | ||
features.PushBack(obj, document.GetAllocator()); | ||
} | ||
document.AddMember("features", features, document.GetAllocator()); | ||
geometries.clear(); | ||
} | ||
std::string toString() { | ||
StringBuffer buffer; | ||
Writer<StringBuffer> writer(buffer); | ||
writer.SetMaxDecimalPlaces(5); | ||
document.Accept(writer); | ||
std::string json(buffer.GetString(), buffer.GetSize()); | ||
return json; | ||
} | ||
void toFile(std::string filename) { | ||
auto fp = std::fopen(filename.c_str(), "w"); | ||
char writeBuffer[65536]; | ||
FileWriteStream os(fp, writeBuffer, sizeof(writeBuffer)); | ||
Writer<FileWriteStream> writer(os); | ||
writer.SetMaxDecimalPlaces(5); | ||
document.Accept(writer); | ||
fclose(fp); | ||
} | ||
}; | ||
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#endif //_GEOJSON_H |