355 lines
12 KiB
C++
355 lines
12 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2014 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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#include "geojson_datasource.hpp"
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#include "geojson_featureset.hpp"
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#include "large_geojson_featureset.hpp"
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#include <fstream>
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#include <algorithm>
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// boost
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#include <boost/algorithm/string.hpp>
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#include <boost/spirit/include/qi.hpp>
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// mapnik
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#include <mapnik/boolean.hpp>
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#include <mapnik/unicode.hpp>
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#include <mapnik/utils.hpp>
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#include <mapnik/feature.hpp>
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#include <mapnik/feature_factory.hpp>
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#include <mapnik/feature_kv_iterator.hpp>
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#include <mapnik/value_types.hpp>
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#include <mapnik/box2d.hpp>
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#include <mapnik/debug.hpp>
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#include <mapnik/proj_transform.hpp>
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#include <mapnik/projection.hpp>
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#include <mapnik/util/geometry_to_ds_type.hpp>
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#include <mapnik/util/variant.hpp>
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#include <mapnik/util/file_io.hpp>
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#include <mapnik/make_unique.hpp>
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#include <mapnik/json/feature_collection_grammar.hpp>
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#include <mapnik/json/extract_bounding_box_grammar_impl.hpp>
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#include <mapnik/util/boost_geometry_adapters.hpp> // boost.geometry - register box2d<double>
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using mapnik::datasource;
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using mapnik::parameters;
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DATASOURCE_PLUGIN(geojson_datasource)
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struct attr_value_converter
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{
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mapnik::eAttributeType operator() (mapnik::value_integer) const
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{
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return mapnik::Integer;
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}
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mapnik::eAttributeType operator() (double) const
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{
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return mapnik::Double;
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}
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mapnik::eAttributeType operator() (float) const
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{
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return mapnik::Double;
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}
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mapnik::eAttributeType operator() (bool) const
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{
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return mapnik::Boolean;
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}
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mapnik::eAttributeType operator() (std::string const& ) const
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{
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return mapnik::String;
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}
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mapnik::eAttributeType operator() (mapnik::value_unicode_string const&) const
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{
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return mapnik::String;
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}
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mapnik::eAttributeType operator() (mapnik::value_null const& ) const
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{
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return mapnik::String;
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}
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};
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geojson_datasource::geojson_datasource(parameters const& params)
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: datasource(params),
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type_(datasource::Vector),
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desc_(geojson_datasource::name(),
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*params.get<std::string>("encoding","utf-8")),
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filename_(),
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inline_string_(),
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extent_(),
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features_(),
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tree_(nullptr)
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{
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boost::optional<std::string> inline_string = params.get<std::string>("inline");
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if (inline_string)
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{
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inline_string_ = *inline_string;
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}
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else
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{
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boost::optional<std::string> file = params.get<std::string>("file");
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if (!file) throw mapnik::datasource_exception("GeoJSON Plugin: missing <file> parameter");
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boost::optional<std::string> base = params.get<std::string>("base");
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if (base)
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filename_ = *base + "/" + *file;
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else
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filename_ = *file;
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}
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if (!inline_string_.empty())
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{
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parse_geojson(inline_string_);
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}
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else
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{
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mapnik::util::file file(filename_);
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if (!file.open())
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{
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throw mapnik::datasource_exception("GeoJSON Plugin: could not open: '" + filename_ + "'");
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}
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std::string file_buffer;
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file_buffer.resize(file.size());
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std::fread(&file_buffer[0], file.size(), 1, file.get());
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cache_features_ = *params.get<mapnik::boolean_type>("cache_features", true);
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if (cache_features_)
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{
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parse_geojson(file_buffer);
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}
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else
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{
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initialise_index(file_buffer.begin(), file_buffer.end());
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}
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}
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}
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namespace {
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using base_iterator_type = std::string::const_iterator;
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const mapnik::transcoder tr("utf8");
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const mapnik::json::feature_collection_grammar<base_iterator_type,mapnik::feature_impl> fc_grammar(tr);
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}
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template <typename Iterator>
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void geojson_datasource::initialise_index(Iterator start, Iterator end)
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{
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mapnik::json::boxes boxes;
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mapnik::json::extract_bounding_box_grammar<Iterator> bbox_grammar;
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boost::spirit::ascii::space_type space;
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if (!boost::spirit::qi::phrase_parse(start, end, (bbox_grammar)(boost::phoenix::ref(boxes)) , space))
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{
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throw mapnik::datasource_exception("GeoJSON Plugin: could not parse: '" + filename_ + "'");
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}
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tree_ = std::make_unique<spatial_index_type>(boxes);
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for (auto const& item : boxes)
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{
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auto const& box = std::get<0>(item);
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auto const& geometry_index = std::get<1>(item);
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if (!extent_.valid())
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{
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extent_ = box;
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// parse first feature to extract attributes schema.
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// NOTE: this doesn't yield correct answer for geoJSON in general, just an indication
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mapnik::util::file file(filename_);
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if (!file.open())
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{
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throw mapnik::datasource_exception("GeoJSON Plugin: could not open: '" + filename_ + "'");
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}
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std::fseek(file.get(), geometry_index.first, SEEK_SET);
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std::vector<char> json;
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json.resize(geometry_index.second);
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std::fread(json.data(), geometry_index.second, 1, file.get());
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using chr_iterator_type = std::vector<char>::const_iterator;
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chr_iterator_type start = json.begin();
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chr_iterator_type end = json.end();
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mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
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mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx,1));
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using namespace boost::spirit;
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static const mapnik::transcoder tr("utf8");
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static const mapnik::json::feature_grammar<chr_iterator_type,mapnik::feature_impl> grammar(tr);
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ascii::space_type space;
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if (!qi::phrase_parse(start, end, (grammar)(boost::phoenix::ref(*feature)), space))
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{
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throw std::runtime_error("Failed to parse geojson feature");
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}
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for ( auto const& kv : *feature)
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{
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desc_.add_descriptor(mapnik::attribute_descriptor(std::get<0>(kv),
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mapnik::util::apply_visitor(attr_value_converter(),
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std::get<1>(kv))));
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}
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}
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else
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{
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extent_.expand_to_include(box);
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}
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}
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}
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template <typename T>
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void geojson_datasource::parse_geojson(T const& buffer)
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{
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boost::spirit::ascii::space_type space;
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mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
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std::size_t start_id = 1;
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mapnik::json::default_feature_callback callback(features_);
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bool result = boost::spirit::qi::phrase_parse(buffer.begin(), buffer.end(), (fc_grammar)
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(boost::phoenix::ref(ctx),boost::phoenix::ref(start_id), boost::phoenix::ref(callback)),
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space);
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if (!result)
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{
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if (!inline_string_.empty()) throw mapnik::datasource_exception("geojson_datasource: Failed parse GeoJSON file from in-memory string");
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else throw mapnik::datasource_exception("geojson_datasource: Failed parse GeoJSON file '" + filename_ + "'");
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}
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using values_container = std::vector< std::pair<box_type, std::pair<std::size_t, std::size_t>>>;
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values_container values;
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values.reserve(features_.size());
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std::size_t geometry_index = 0;
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for (mapnik::feature_ptr const& f : features_)
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{
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mapnik::box2d<double> box = f->envelope();
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if (box.valid())
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{
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if (geometry_index == 0)
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{
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extent_ = box;
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for ( auto const& kv : *f)
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{
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desc_.add_descriptor(mapnik::attribute_descriptor(std::get<0>(kv),
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mapnik::util::apply_visitor(attr_value_converter(),
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std::get<1>(kv))));
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}
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}
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else
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{
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extent_.expand_to_include(box);
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}
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}
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values.emplace_back(box, std::make_pair(geometry_index,0));
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++geometry_index;
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}
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// packing algorithm
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tree_ = std::make_unique<spatial_index_type>(values);
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}
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geojson_datasource::~geojson_datasource() { }
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const char * geojson_datasource::name()
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{
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return "geojson";
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}
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boost::optional<mapnik::datasource::geometry_t> geojson_datasource::get_geometry_type() const
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{
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boost::optional<mapnik::datasource::geometry_t> result;
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int multi_type = 0;
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unsigned num_features = features_.size();
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for (unsigned i = 0; i < num_features && i < 5; ++i)
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{
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mapnik::util::to_ds_type(features_[i]->paths(),result);
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if (result)
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{
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int type = static_cast<int>(*result);
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if (multi_type > 0 && multi_type != type)
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{
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result.reset(mapnik::datasource::Collection);
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return result;
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}
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multi_type = type;
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}
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}
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return result;
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}
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mapnik::datasource::datasource_t geojson_datasource::type() const
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{
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return type_;
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}
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mapnik::box2d<double> geojson_datasource::envelope() const
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{
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return extent_;
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}
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mapnik::layer_descriptor geojson_datasource::get_descriptor() const
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{
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return desc_;
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}
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mapnik::featureset_ptr geojson_datasource::features(mapnik::query const& q) const
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{
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// if the query box intersects our world extent then query for features
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mapnik::box2d<double> const& box = q.get_bbox();
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if (extent_.intersects(box))
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{
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geojson_featureset::array_type index_array;
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if (tree_)
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{
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tree_->query(boost::geometry::index::intersects(box),std::back_inserter(index_array));
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if (cache_features_)
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{
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return std::make_shared<geojson_featureset>(features_, std::move(index_array));
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}
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else
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{
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std::sort(index_array.begin(),index_array.end(),
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[] (item_type const& item0, item_type const& item1)
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{
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return item0.second.first < item1.second.first;
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});
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return std::make_shared<large_geojson_featureset>(filename_, std::move(index_array));
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}
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}
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}
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// otherwise return an empty featureset pointer
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return mapnik::featureset_ptr();
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}
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mapnik::featureset_ptr geojson_datasource::features_at_point(mapnik::coord2d const& pt, double tol) const
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{
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mapnik::box2d<double> query_bbox(pt, pt);
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query_bbox.pad(tol);
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mapnik::query q(query_bbox);
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std::vector<mapnik::attribute_descriptor> const& desc = desc_.get_descriptors();
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std::vector<mapnik::attribute_descriptor>::const_iterator itr = desc.begin();
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std::vector<mapnik::attribute_descriptor>::const_iterator end = desc.end();
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for ( ;itr!=end;++itr)
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{
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q.add_property_name(itr->get_name());
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}
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return features(q);
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}
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