mapnik/plugins/input/osm/osm_datasource.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 <fstream>
#include <stdexcept>
#include <mapnik/geom_util.hpp>
#include <mapnik/query.hpp>
#include "osm_datasource.hpp"
#include "osm_featureset.hpp"
#include <set>

DATASOURCE_PLUGIN(osm_datasource)

using mapnik::String;
using mapnik::Double;
using mapnik::Integer;
using mapnik::datasource_exception;
using mapnik::filter_in_box;
using mapnik::filter_at_point;
using mapnik::attribute_descriptor;

const std::string osm_datasource::name_ = "osm";

osm_datasource::osm_datasource(const parameters &params)
   : datasource (params),
     type_(datasource::Vector),
	 desc_(*params.get<std::string>("type"), *params.get<std::string>("encoding","utf-8")) 
{
	osm_data_ = new osm_dataset;
	std::string osm_filename= *params.get<std::string>("file","");
	std::string parser = *params.get<std::string>("parser","libxml2");
	// load the data
	if (osm_data_->load(osm_filename.c_str(),parser)==false)
	{
		throw datasource_exception("Error loading OSM data");
	}	

	osm_data_->rewind();
	// Need code to get the attributes of all the data
	std::set<std::string> keys= osm_data_->get_keys();

	// Add the attributes to the datasource descriptor - assume they're
	// all of type String
	for(std::set<std::string>::iterator i=keys.begin(); i!=keys.end(); i++)
		desc_.add_descriptor(attribute_descriptor(*i,String));

	// Get the bounds of the data and set extent_ accordingly
	bounds b = osm_data_->get_bounds();
	extent_ =  Envelope<double>(b.w,b.s,b.e,b.n);
}

osm_datasource::~osm_datasource() { delete osm_data_; }


int osm_datasource::type() const
{
   return type_;
}

layer_descriptor osm_datasource::get_descriptor() const
{
   return desc_;
}

featureset_ptr osm_datasource::features(const query& q) const
{
   filter_in_box filter(q.get_bbox());
	// so we need to filter osm features by bbox here...
	
	return featureset_ptr
         (new osm_featureset<filter_in_box>(filter,
                                              osm_data_,
                                              q.property_names(),
                                              desc_.get_encoding()));
}

featureset_ptr osm_datasource::features_at_point(coord2d const& pt) const
{
   filter_at_point filter(pt);
   // collect all attribute names
   std::vector<attribute_descriptor> const& desc_vector = 
		desc_.get_descriptors();
   std::vector<attribute_descriptor>::const_iterator itr = desc_vector.begin();
   std::vector<attribute_descriptor>::const_iterator end = desc_vector.end();
   std::set<std::string> names;
    
   while (itr != end)
   {    
      names.insert(itr->get_name());
      ++itr;
   }
    
	return featureset_ptr
         (new osm_featureset<filter_at_point>(filter,
                                                osm_data_,
                                                names,
                                                desc_.get_encoding()));
}

Envelope<double> osm_datasource::envelope() const
{
   return extent_;
}