mapnik/plugins/input/gdal/gdal_datasource.cpp

129 lines
3.5 KiB
C++

/*****************************************************************************
*
* 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),
extent_(),
desc_(*params.get<std::string>("type"),"utf-8")
{
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();
double tr[6];
dataset->GetGeoTransform(tr);
double x0 = tr[0];
double y0 = tr[3];
double x1 = tr[0] + dataset->GetRasterXSize()*tr[1] + dataset->GetRasterYSize()*tr[2];
double y1 = tr[3] + dataset->GetRasterXSize()*tr[4] + dataset->GetRasterYSize()*tr[5];
extent_.init(x0,y0,x1,y1);
GDALClose(dataset);
}
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));
}