mapnik/plugins/input/geojson/geojson_datasource.cpp

284 lines
8.6 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2014 Artem Pavlenko
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
#include "geojson_datasource.hpp"
#include "geojson_featureset.hpp"
#include <fstream>
#include <algorithm>
// boost
#include <boost/algorithm/string.hpp>
#include <boost/spirit/include/qi.hpp>
// mapnik
#include <mapnik/unicode.hpp>
#include <mapnik/utils.hpp>
#include <mapnik/feature.hpp>
#include <mapnik/feature_kv_iterator.hpp>
#include <mapnik/value_types.hpp>
#include <mapnik/box2d.hpp>
#include <mapnik/debug.hpp>
#include <mapnik/proj_transform.hpp>
#include <mapnik/projection.hpp>
#include <mapnik/util/geometry_to_ds_type.hpp>
#include <mapnik/util/variant.hpp>
#include <mapnik/util/file_io.hpp>
#include <mapnik/make_unique.hpp>
#include <mapnik/json/feature_collection_grammar.hpp>
#include <mapnik/polygon_clipper.hpp> // boost::geometry - register box2d<double>
using mapnik::datasource;
using mapnik::parameters;
DATASOURCE_PLUGIN(geojson_datasource)
struct attr_value_converter
{
mapnik::eAttributeType operator() (mapnik::value_integer) const
{
return mapnik::Integer;
}
mapnik::eAttributeType operator() (double) const
{
return mapnik::Double;
}
mapnik::eAttributeType operator() (float) const
{
return mapnik::Double;
}
mapnik::eAttributeType operator() (bool) const
{
return mapnik::Boolean;
}
mapnik::eAttributeType operator() (std::string const& ) const
{
return mapnik::String;
}
mapnik::eAttributeType operator() (mapnik::value_unicode_string const&) const
{
return mapnik::String;
}
mapnik::eAttributeType operator() (mapnik::value_null const& ) const
{
return mapnik::String;
}
};
geojson_datasource::geojson_datasource(parameters const& params)
: datasource(params),
type_(datasource::Vector),
desc_(geojson_datasource::name(),
*params.get<std::string>("encoding","utf-8")),
filename_(),
inline_string_(),
extent_(),
features_(),
tree_(nullptr)
{
boost::optional<std::string> inline_string = params.get<std::string>("inline");
if (inline_string)
{
inline_string_ = *inline_string;
}
else
{
boost::optional<std::string> file = params.get<std::string>("file");
if (!file) throw mapnik::datasource_exception("GeoJSON Plugin: missing <file> parameter");
boost::optional<std::string> base = params.get<std::string>("base");
if (base)
filename_ = *base + "/" + *file;
else
filename_ = *file;
}
if (!inline_string_.empty())
{
parse_geojson(inline_string_);
}
else
{
mapnik::util::file file(filename_);
if (!file.open())
{
throw mapnik::datasource_exception("GeoJSON Plugin: could not open: '" + filename_ + "'");
}
std::string file_buffer;
file_buffer.resize(file.size());
std::fread(&file_buffer[0], file.size(), 1, file.get());
parse_geojson(file_buffer);
}
}
namespace {
using base_iterator_type = std::string::const_iterator;
const mapnik::transcoder tr("utf8");
const mapnik::json::feature_collection_grammar<base_iterator_type,mapnik::feature_impl> fc_grammar(tr);
}
template <typename T>
void geojson_datasource::parse_geojson(T const& buffer)
{
boost::spirit::standard_wide::space_type space;
mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
std::size_t start_id = 1;
bool result = boost::spirit::qi::phrase_parse(buffer.begin(), buffer.end(), (fc_grammar)
(boost::phoenix::ref(ctx),boost::phoenix::ref(start_id)),
space, features_);
if (!result)
{
if (!inline_string_.empty()) throw mapnik::datasource_exception("geojson_datasource: Failed parse GeoJSON file from in-memory string");
else throw mapnik::datasource_exception("geojson_datasource: Failed parse GeoJSON file '" + filename_ + "'");
}
#if BOOST_VERSION >= 105600
using values_container = std::vector< std::pair<box_type, std::pair<std::size_t, std::size_t>>>;
values_container values;
values.reserve(features_.size());
#else
tree_ = std::make_unique<spatial_index_type>(16, 4);
#endif
std::size_t geometry_index = 0;
for (mapnik::feature_ptr const& f : features_)
{
mapnik::box2d<double> box = f->envelope();
if (box.valid())
{
if (geometry_index == 0)
{
extent_ = box;
for ( auto const& kv : *f)
{
desc_.add_descriptor(mapnik::attribute_descriptor(std::get<0>(kv),
mapnik::util::apply_visitor(attr_value_converter(),
std::get<1>(kv))));
}
}
else
{
extent_.expand_to_include(box);
}
}
#if BOOST_VERSION >= 105600
values.emplace_back(box, std::make_pair(geometry_index,0));
#else
tree_->insert(box, std::make_pair(geometry_index));
#endif
++geometry_index;
}
#if BOOST_VERSION >= 105600
// packing algorithm
tree_ = std::make_unique<spatial_index_type>(values);
#endif
}
geojson_datasource::~geojson_datasource() { }
const char * geojson_datasource::name()
{
return "geojson";
}
boost::optional<mapnik::datasource::geometry_t> geojson_datasource::get_geometry_type() const
{
boost::optional<mapnik::datasource::geometry_t> result;
int multi_type = 0;
unsigned num_features = features_.size();
for (unsigned i = 0; i < num_features && i < 5; ++i)
{
mapnik::util::to_ds_type(features_[i]->paths(),result);
if (result)
{
int type = static_cast<int>(*result);
if (multi_type > 0 && multi_type != type)
{
result.reset(mapnik::datasource::Collection);
return result;
}
multi_type = type;
}
}
return result;
}
mapnik::datasource::datasource_t geojson_datasource::type() const
{
return type_;
}
mapnik::box2d<double> geojson_datasource::envelope() const
{
return extent_;
}
mapnik::layer_descriptor geojson_datasource::get_descriptor() const
{
return desc_;
}
mapnik::featureset_ptr geojson_datasource::features(mapnik::query const& q) const
{
// if the query box intersects our world extent then query for features
mapnik::box2d<double> const& box = q.get_bbox();
if (extent_.intersects(box))
{
#if BOOST_VERSION >= 105600
geojson_featureset::array_type index_array;
if (tree_)
{
tree_->query(boost::geometry::index::intersects(box),std::back_inserter(index_array));
return std::make_shared<geojson_featureset>(features_, std::move(index_array));
}
#else
if (tree_)
{
return std::make_shared<geojson_featureset>(features_, tree_->find(box));
}
#endif
}
// otherwise return an empty featureset pointer
return mapnik::featureset_ptr();
}
mapnik::featureset_ptr geojson_datasource::features_at_point(mapnik::coord2d const& pt, double tol) const
{
mapnik::box2d<double> query_bbox(pt, pt);
query_bbox.pad(tol);
mapnik::query q(query_bbox);
std::vector<mapnik::attribute_descriptor> const& desc = desc_.get_descriptors();
std::vector<mapnik::attribute_descriptor>::const_iterator itr = desc.begin();
std::vector<mapnik::attribute_descriptor>::const_iterator end = desc.end();
for ( ;itr!=end;++itr)
{
q.add_property_name(itr->get_name());
}
return features(q);
}