mapnik/plugins/input/osm/osm_featureset.cpp

/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2006 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 <iostream>
#include "osm_featureset.hpp"
#include <mapnik/geometry.hpp>

using mapnik::Feature;
using mapnik::feature_ptr;
using mapnik::geometry_type;
using std::cerr;
using std::endl;

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)),
      count_(0),
      dataset_ (dataset),
      attribute_names_ (attribute_names)
{
    dataset_->rewind();
}


template <typename filterT>
feature_ptr osm_featureset<filterT>::next()
{
    osm_item * cur_item = dataset_->next_item();
    feature_ptr feature;
    bool success=false;
    if(cur_item != NULL)
    {
        if(dataset_->current_item_is_node())
        {
            feature= feature_ptr(new Feature(count_++));
            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_ptr(new Feature(count_++));
                    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>;