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::box2d;
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
{

#ifdef MAPNIK_DEBUG
    std::clog << "GDAL Plugin: opening: " << dataset_name_ << "\n";
#endif

    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, bool bind)
    : datasource(params),
      desc_(*params.get<std::string>("type"),"utf-8"),
      filter_factor_(*params_.get<double>("filter_factor",0.0))
{

#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;
   
    if (bind)
    {
        this->bind();
    }
}

void gdal_datasource::bind() const
{
    if (is_bound_) return;
    
    shared_dataset_ = *params_.get<mapnik::boolean>("shared",false);
    band_ = *params_.get<int>("band", -1);

    GDALDataset *dataset = open_dataset();
   
    nbands_ = dataset->GetRasterCount();
    width_ = dataset->GetRasterXSize();
    height_ = dataset->GetRasterYSize();


    double tr[6];
    dataset->GetGeoTransform(tr);
    if (tr[2] !=0 || tr[4] != 0)
    {
        throw datasource_exception("GDAL Plugin: only 'north up' images are supported");
    }

    dx_ = tr[1];
    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_;
     
    /*
    double x0 = tr[0] + (height_) * tr[2]; // minx
    double y0 = tr[3] + (height_) * tr[5]; // miny
    
    double x1 = tr[0] + (width_) * tr[1]; // maxx
    double y1 = tr[3] + (width_) * tr[4]; // maxy
    */
    
    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

    is_bound_ = true;
}

gdal_datasource::~gdal_datasource() {}

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

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

box2d<double> gdal_datasource::envelope() const
{
    if (!is_bound_) bind();
    
    return extent_;
}

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

featureset_ptr gdal_datasource::features(query const& q) const
{
    if (!is_bound_) bind();

    gdal_query gq = q;
    return featureset_ptr(new gdal_featureset(*open_dataset(), band_, gq, extent_, width_, height_, nbands_, dx_, dy_, filter_factor_));
}

featureset_ptr gdal_datasource::features_at_point(coord2d const& pt) const
{
    if (!is_bound_) bind();

    gdal_query gq = pt;
    return featureset_ptr(new gdal_featureset(*open_dataset(), band_, gq, extent_, width_, height_, nbands_, dx_, dy_,  filter_factor_));
}