mapnik/plugins/input/osm/osm_featureset.cpp

/*****************************************************************************
 *
 * 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
 *
 *****************************************************************************/

// stl
#include <iostream>

// mapnik
#include <mapnik/geometry.hpp>
#include <mapnik/feature_factory.hpp>

#include "osm_featureset.hpp"

using mapnik::Feature;
using mapnik::feature_ptr;
using mapnik::geometry_type;
using mapnik::feature_factory;

template <typename filterT>
osm_featureset<filterT>::osm_featureset(const filterT& filter,
                                        osm_dataset* dataset,
                                        const std::set<std::string>&
                                        attribute_names,
                                        std::string const& encoding)
    : filter_(filter),
      query_ext_(),
      tr_(new transcoder(encoding)),
      feature_id_(1),
      dataset_ (dataset),
      attribute_names_ (attribute_names)
{
    dataset_->rewind();
}

template <typename filterT>
feature_ptr osm_featureset<filterT>::next()
{
    feature_ptr feature;
    bool success = false;

    osm_item* cur_item = dataset_->next_item();
    if (cur_item != NULL)
    {
        if (dataset_->current_item_is_node())
        {
            feature = feature_factory::create(feature_id_);
            ++feature_id_;
            double lat = static_cast<osm_node*>(cur_item)->lat;
            double lon = static_cast<osm_node*>(cur_item)->lon;
            geometry_type* point = new geometry_type(mapnik::Point);
            point->move_to(lon, lat);
            feature->add_geometry(point);
            success = true;
        }
        else if (dataset_->current_item_is_way())
        {
            bounds b = static_cast<osm_way*>(cur_item)->get_bounds();

            // Loop until we find a feature which passes the filter
            while (cur_item != NULL &&
                   ! filter_.pass(box2d<double>(b.w, b.s, b.e, b.n)))
            {
                cur_item = dataset_->next_item();
                if (cur_item != NULL)
                {
                    b = static_cast<osm_way*>(cur_item)->get_bounds();
                }
            }

            if (cur_item != NULL)
            {
                if (static_cast<osm_way*>(cur_item)->nodes.size())
                {
                    feature = feature_factory::create(feature_id_);
                    ++feature_id_;
                    geometry_type* geom;
                    if (static_cast<osm_way*>(cur_item)->is_polygon())
                    {
                        geom = new geometry_type(mapnik::Polygon);
                    }
                    else
                    {
                        geom = new geometry_type(mapnik::LineString);
                    }

                    geom->set_capacity(static_cast<osm_way*>(cur_item)->nodes.size());
                    geom->move_to(static_cast<osm_way*>(cur_item)->nodes[0]->lon,
                                  static_cast<osm_way*>(cur_item)->nodes[0]->lat);

                    for (unsigned int count = 1;
                         count < static_cast<osm_way*>(cur_item)->nodes.size();
                         count++)
                    {
                        geom->line_to(static_cast<osm_way*>(cur_item)->nodes[count]->lon,
                                      static_cast<osm_way*>(cur_item)->nodes[count]->lat);
                    }
                    feature->add_geometry(geom);
                    success = true;
                }
            }
        }

        // can feature_ptr be compared to NULL? - no
        if (success)
        {
            std::map<std::string,std::string>::iterator i = cur_item->keyvals.begin();

            // add the keyvals to the feature. the feature seems to be a map
            // of some sort so this should work - see dbf_file::add_attribute()
            while (i != cur_item->keyvals.end())
            {
                // only add if in the specified set of attribute names
                if (attribute_names_.find(i->first) != attribute_names_.end())
                {
                    (*feature)[i->first] = tr_->transcode(i->second.c_str());
                }

                i++;
            }

            return feature;
        }
    }
    return feature_ptr();
}

template <typename filterT>
osm_featureset<filterT>::~osm_featureset() {}

template class osm_featureset<mapnik::filter_in_box>;
template class osm_featureset<mapnik::filter_at_point>;