+ geojson input plugin (thanks, @tmcw!)

SConstruct

@@ -102,6 +102,7 @@ PLUGINS = { # plugins with external dependencies
             'shape':   {'default':True,'path':None,'inc':None,'lib':None,'lang':'C++'},
             'csv':     {'default':True,'path':None,'inc':None,'lib':None,'lang':'C++'},
             'raster':  {'default':True,'path':None,'inc':None,'lib':None,'lang':'C++'},
+            'geojson': {'default':True,'path':None,'inc':None,'lib':None,'lang':'C++'},
             'kismet':  {'default':False,'path':None,'inc':None,'lib':None,'lang':'C++'},
             }
 

plugins/input/geojson/build.py

@@ -0,0 +1,51 @@
+#
+# This file is part of Mapnik (c++ mapping toolkit)
+#
+# Copyright (C) 2012 Artem Pavlenko
+#
+# Mapnik 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
+#
+
+
+Import ('plugin_base')
+Import ('env')
+
+prefix = env['PREFIX']
+
+plugin_env = plugin_base.Clone()
+
+geojson_src = Split(
+  """
+  geojson_datasource.cpp
+  geojson_featureset.cpp      
+  """
+        )
+
+libraries = []
+# Link Library to Dependencies
+libraries.append('mapnik')
+libraries.append(env['ICU_LIB_NAME'])
+libraries.append('boost_system%s' % env['BOOST_APPEND'])
+if env['THREADING'] == 'multi':
+    libraries.append('boost_thread%s' % env['BOOST_APPEND'])
+
+input_plugin = plugin_env.SharedLibrary('../geojson', source=geojson_src, SHLIBPREFIX='', SHLIBSUFFIX='.input', LIBS=libraries, LINKFLAGS=env['CUSTOM_LDFLAGS'])
+
+# if the plugin links to libmapnik ensure it is built first
+Depends(input_plugin, env.subst('../../../src/%s' % env['MAPNIK_LIB_NAME']))
+
+if 'uninstall' not in COMMAND_LINE_TARGETS:
+    env.Install(env['MAPNIK_INPUT_PLUGINS_DEST'], input_plugin)
+    env.Alias('install', env['MAPNIK_INPUT_PLUGINS_DEST'])

plugins/input/geojson/geojson_datasource.cpp

@@ -0,0 +1,165 @@
+/*****************************************************************************
+ *
+ * This file is part of Mapnik (c++ mapping toolkit)
+ *
+ * Copyright (C) 2012 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 <iostream>
+
+// boost
+#include <boost/make_shared.hpp>
+#include <boost/algorithm/string.hpp>
+#include <boost/spirit/include/support_multi_pass.hpp>
+#include <boost/foreach.hpp>
+#include <boost/geometry/geometries/box.hpp>
+#include <boost/geometry/geometries/geometries.hpp>
+#include <boost/geometry.hpp>
+#include <boost/geometry/extensions/index/rtree/rtree.hpp>
+// mapnik
+#include <mapnik/box2d.hpp>
+#include <mapnik/proj_transform.hpp>
+#include <mapnik/projection.hpp>
+#include <mapnik/json/feature_collection_parser.hpp>
+
+using mapnik::datasource;
+using mapnik::parameters;
+
+DATASOURCE_PLUGIN(geojson_datasource)
+
+geojson_datasource::geojson_datasource(parameters const& params, bool bind)
+: datasource(params),
+    type_(datasource::Vector),
+    desc_(*params_.get<std::string>("type"),
+          *params_.get<std::string>("encoding","utf-8")),
+    file_(*params_.get<std::string>("file","")),
+    extent_(),
+    tr_(new mapnik::transcoder(*params_.get<std::string>("encoding","utf-8"))),
+    features_(),
+    tree_(16,1)
+{
+    if (file_.empty()) throw mapnik::datasource_exception("GeoJSON Plugin: missing <file> parameter");
+    if (bind)
+    {
+        this->bind();
+    }
+}
+
+void geojson_datasource::bind() const
+{
+    if (is_bound_) return;
+
+    typedef std::istreambuf_iterator<char> base_iterator_type;    
+    
+    std::ifstream is(file_.c_str());
+    boost::spirit::multi_pass<base_iterator_type> begin = 
+        boost::spirit::make_default_multi_pass(base_iterator_type(is));
+
+    boost::spirit::multi_pass<base_iterator_type> end = 
+        boost::spirit::make_default_multi_pass(base_iterator_type());
+    
+    mapnik::context_ptr ctx = boost::make_shared<mapnik::context_type>();
+    mapnik::json::feature_collection_parser<boost::spirit::multi_pass<base_iterator_type> > p(ctx,*tr_);
+    bool result = p.parse(begin,end, features_);
+    if (!result) 
+    {
+        MAPNIK_LOG_WARN(geojson) << "geojson_datasource: Failed parse GeoJSON file " << file_;
+        return;
+    }
+    
+    bool first = true;
+    std::size_t count=0;
+    BOOST_FOREACH (mapnik::feature_ptr f, features_)
+    {
+        mapnik::box2d<double> const& box = f->envelope();
+        if (first) 
+        {
+            extent_ = box;
+            first = false;
+        }
+        else
+        {
+            extent_.expand_to_include(box);
+        }       
+        tree_.insert(box_type(point_type(box.minx(),box.miny()),point_type(box.maxx(),box.maxy())), count++);
+    }
+    is_bound_ = true;
+}
+
+geojson_datasource::~geojson_datasource() { }
+
+std::string const geojson_datasource::name_="geojson";
+
+std::string geojson_datasource::name()
+{
+    return name_;
+}
+
+boost::optional<mapnik::datasource::geometry_t> geojson_datasource::get_geometry_type() const 
+{
+    return boost::optional<mapnik::datasource::geometry_t>();
+}
+
+mapnik::datasource::datasource_t geojson_datasource::type() const 
+{
+    return type_;
+}
+
+std::map<std::string, mapnik::parameters> geojson_datasource::get_statistics() const 
+{
+    return statistics_;
+}
+
+// FIXME: implement
+mapnik::box2d<double> geojson_datasource::envelope() const
+{
+    if (!is_bound_) bind();
+
+    return extent_;
+}
+
+mapnik::layer_descriptor geojson_datasource::get_descriptor() const
+{
+    if (!is_bound_) bind();
+
+    return desc_;
+}
+
+mapnik::featureset_ptr geojson_datasource::features(mapnik::query const& q) const
+{
+    if (!is_bound_) bind();
+    
+    // if the query box intersects our world extent then query for features
+    if (extent_.intersects(q.get_bbox()))
+    {
+        return boost::make_shared<geojson_featureset>(features_,tree_);
+    }    
+    // otherwise return an empty featureset pointer
+    return mapnik::featureset_ptr();
+}
+
+// FIXME
+mapnik::featureset_ptr geojson_datasource::features_at_point(mapnik::coord2d const& pt) const
+{
+    if (!is_bound_) bind();
+    return mapnik::featureset_ptr();
+}

plugins/input/geojson/geojson_datasource.hpp

@@ -0,0 +1,68 @@
+/*****************************************************************************
+ *
+ * This file is part of Mapnik (c++ mapping toolkit)
+ *
+ * Copyright (C) 2012 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
+ *
+ *****************************************************************************/
+
+#ifndef GEOJSON_DATASOURCE_HPP
+#define GEOJSON_DATASOURCE_HPP
+
+// mapnik
+#include <mapnik/datasource.hpp>
+// boost
+#include <boost/geometry/geometries/box.hpp>
+#include <boost/geometry/geometries/point_xy.hpp>
+#include <boost/geometry/algorithms/area.hpp>
+#include <boost/geometry/extensions/index/rtree/rtree.hpp>
+#include <boost/geometry/geometries/geometries.hpp>
+#include <boost/geometry/extensions/index/rtree/rtree.hpp>
+
+class geojson_datasource : public mapnik::datasource
+{
+public:
+    typedef boost::geometry::model::d2::point_xy<double> point_type;
+    typedef boost::geometry::model::box<point_type> box_type;
+    typedef boost::geometry::index::rtree<box_type,std::size_t> spatial_index_type;
+    
+    // constructor
+    geojson_datasource(mapnik::parameters const& params, bool bind=true);
+    virtual ~geojson_datasource ();
+    mapnik::datasource::datasource_t type() const;
+    static std::string name();
+    mapnik::featureset_ptr features(mapnik::query const& q) const;
+    mapnik::featureset_ptr features_at_point(mapnik::coord2d const& pt) const;
+    mapnik::box2d<double> envelope() const;
+    mapnik::layer_descriptor get_descriptor() const;
+    std::map<std::string, mapnik::parameters> get_statistics() const;
+    boost::optional<mapnik::datasource::geometry_t> get_geometry_type() const;
+    void bind() const;
+private:    
+    static const std::string name_;
+    mapnik::datasource::datasource_t type_;
+    mutable std::map<std::string, mapnik::parameters> statistics_;
+    mutable mapnik::layer_descriptor desc_;
+    mutable std::string file_;
+    mutable mapnik::box2d<double> extent_;
+    boost::shared_ptr<mapnik::transcoder> tr_;
+    mutable std::vector<mapnik::feature_ptr> features_;
+    mutable spatial_index_type tree_;
+};
+
+
+#endif // FILE_DATASOURCE_HPP

plugins/input/geojson/geojson_featureset.cpp

@@ -0,0 +1,51 @@
+/*****************************************************************************
+ *
+ * This file is part of Mapnik (c++ mapping toolkit)
+ *
+ * Copyright (C) 2011 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
+ *
+ *****************************************************************************/
+
+// mapnik
+#include <mapnik/feature.hpp>
+// stl
+#include <string>
+#include <vector>
+#include <fstream>
+
+#include "geojson_featureset.hpp"
+
+geojson_featureset::geojson_featureset(std::vector<mapnik::feature_ptr> const& features,
+                                       geojson_datasource::spatial_index_type const& tree)
+    : feature_id_(1),
+      features_(features),
+      tree_(tree) {}
+
+geojson_featureset::~geojson_featureset() {}
+
+mapnik::feature_ptr geojson_featureset::next()
+{
+    feature_id_++;
+    if (feature_id_ <= features_.size())
+    {
+        return features_.at(feature_id_ - 1);
+    }
+    else
+    {
+        return mapnik::feature_ptr();
+    }
+}

plugins/input/geojson/geojson_featureset.hpp

@@ -0,0 +1,23 @@
+#ifndef GEOJSON_FEATURESET_HPP
+#define GEOJSON_FEATURESET_HPP
+
+#include <mapnik/datasource.hpp>
+#include <vector>
+#include "geojson_datasource.hpp"
+
+class geojson_featureset : public mapnik::Featureset
+{
+public:
+    geojson_featureset(std::vector<mapnik::feature_ptr> const& features,
+                       geojson_datasource::spatial_index_type const& tree);
+    virtual ~geojson_featureset();
+    mapnik::feature_ptr next();
+
+private:
+    mapnik::box2d<double> box_;
+    unsigned int feature_id_;
+    std::vector<mapnik::feature_ptr> const& features_;
+    geojson_datasource::spatial_index_type const& tree_;
+};
+
+#endif // GEOJSON_FEATURESET_HPP