mapnik/plugins/input/gdal/gdal_datasource.cpp

/*****************************************************************************
 * 
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2007 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
 *
 *****************************************************************************/
// $Id$

#include "gdal_datasource.hpp"
#include "gdal_featureset.hpp"

// mapnik
#include <mapnik/ptree_helpers.hpp>
#include <mapnik/geom_util.hpp>

using mapnik::datasource;
using mapnik::parameters;

DATASOURCE_PLUGIN(gdal_datasource)

using mapnik::Envelope;
using mapnik::coord2d;
using mapnik::query;
using mapnik::featureset_ptr;
using mapnik::layer_descriptor;
using mapnik::datasource_exception;



/*
 * Opens a GDALDataset and returns a pointer to it.
 * Caller is responsible for calling GDALClose on it
 */
inline GDALDataset *gdal_datasource::open_dataset() const
{
   GDALDataset *dataset;
#if GDAL_VERSION_NUM >= 1600
   if (shared_dataset_)
       dataset = reinterpret_cast<GDALDataset*>(GDALOpenShared((dataset_name_).c_str(),GA_ReadOnly));
   else
#endif
       dataset = reinterpret_cast<GDALDataset*>(GDALOpen((dataset_name_).c_str(),GA_ReadOnly));

   if (! dataset) throw datasource_exception(CPLGetLastErrorMsg());
   return dataset;
}



gdal_datasource::gdal_datasource(parameters const& params)
   : datasource(params),
     desc_(*params.get<std::string>("type"),"utf-8")
{

#ifdef MAPNIK_DEBUG
   std::clog << "\nGDAL Plugin: Initializing...\n";
#endif

   GDALAllRegister();

   boost::optional<std::string> file = params.get<std::string>("file");
   if (!file) throw datasource_exception("missing <file> parameter");

   boost::optional<std::string> base = params.get<std::string>("base");
   if (base)
      dataset_name_ = *base + "/" + *file;
   else
      dataset_name_ = *file;

   shared_dataset_ = *params_.get<mapnik::boolean>("shared",false);
   band_ = *params_.get<int>("band", -1);

   GDALDataset *dataset = open_dataset();
   
   // TODO: Make more class attributes from geotransform...
   width_ = dataset->GetRasterXSize();
   height_ = dataset->GetRasterYSize();

   double tr[6];
   dataset->GetGeoTransform(tr);
   double dx = tr[1];
   double dy = tr[5];
   double x0 = tr[0];
   double y0 = tr[3];
   double x1 = tr[0] + width_ * dx + height_ *tr[2];
   double y1 = tr[3] + width_ *tr[4] + height_ * dy;
   extent_.init(x0,y0,x1,y1);
   GDALClose(dataset);
   
#ifdef MAPNIK_DEBUG
   std::clog << "GDAL Plugin: Raster Size=" << width_ << "," << height_ << "\n";
   std::clog << "GDAL Plugin: Raster Extent=" << extent_ << "\n";
#endif

}

gdal_datasource::~gdal_datasource() {}

int gdal_datasource::type() const
{
   return datasource::Raster;
}

std::string gdal_datasource::name()
{
   return "gdal";
}

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

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

featureset_ptr gdal_datasource::features(query const& q) const
{
   gdal_query gq = q;
   return featureset_ptr(new gdal_featureset(*open_dataset(), band_, gq));
}

featureset_ptr gdal_datasource::features_at_point(coord2d const& pt) const
{
   gdal_query gq = pt;
   return featureset_ptr(new gdal_featureset(*open_dataset(), band_, gq));
}