qgsgdalutils.cpp

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/***************************************************************************
                             qgsgdalutils.cpp
                             ----------------
    begin                : September 2018
    copyright            : (C) 2018 Even Rouault
    email                : even.rouault at spatialys.com
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#include "qgsgdalutils.h"

#define CPL_SUPRESS_CPLUSPLUS  //#spellok
#include "gdal.h"
#include "cpl_string.h"

#include <QString>

bool QgsGdalUtils::supportsRasterCreate( GDALDriverH driver )
{
  QString driverShortName = GDALGetDriverShortName( driver );
  if ( driverShortName == QLatin1String( "SQLite" ) )
  {
    // it supports Create() but only for vector side
    return false;
  }
  char **driverMetadata = GDALGetMetadata( driver, nullptr );
  return  CSLFetchBoolean( driverMetadata, GDAL_DCAP_CREATE, false ) &&
          CSLFetchBoolean( driverMetadata, GDAL_DCAP_RASTER, false );
}

gdal::dataset_unique_ptr QgsGdalUtils::createSingleBandMemoryDataset( GDALDataType dataType, QgsRectangle extent, int width, int height, const QgsCoordinateReferenceSystem &crs )
{
  GDALDriverH hDriverMem = GDALGetDriverByName( "MEM" );
  if ( !hDriverMem )
  {
    return gdal::dataset_unique_ptr();
  }

  gdal::dataset_unique_ptr hSrcDS( GDALCreate( hDriverMem, "", width, height, 1, dataType, nullptr ) );

  double cellSizeX = extent.width() / width;
  double cellSizeY = extent.height() / height;
  double geoTransform[6];
  geoTransform[0] = extent.xMinimum();
  geoTransform[1] = cellSizeX;
  geoTransform[2] = 0;
  geoTransform[3] = extent.yMinimum() + ( cellSizeY * height );
  geoTransform[4] = 0;
  geoTransform[5] = -cellSizeY;

  GDALSetProjection( hSrcDS.get(), crs.toWkt().toLatin1().constData() );
  GDALSetGeoTransform( hSrcDS.get(), geoTransform );
  return hSrcDS;
}

gdal::dataset_unique_ptr QgsGdalUtils::createSingleBandTiffDataset( QString filename, GDALDataType dataType, QgsRectangle extent, int width, int height, const QgsCoordinateReferenceSystem &crs )
{
  double cellSizeX = extent.width() / width;
  double cellSizeY = extent.height() / height;
  double geoTransform[6];
  geoTransform[0] = extent.xMinimum();
  geoTransform[1] = cellSizeX;
  geoTransform[2] = 0;
  geoTransform[3] = extent.yMinimum() + ( cellSizeY * height );
  geoTransform[4] = 0;
  geoTransform[5] = -cellSizeY;

  GDALDriverH hDriver = GDALGetDriverByName( "GTiff" );
  if ( !hDriver )
  {
    return gdal::dataset_unique_ptr();
  }

  // Create the output file.
  gdal::dataset_unique_ptr hDstDS( GDALCreate( hDriver, filename.toLocal8Bit().constData(), width, height, 1, dataType, nullptr ) );
  if ( !hDstDS )
  {
    return gdal::dataset_unique_ptr();
  }

  // Write out the projection definition.
  GDALSetProjection( hDstDS.get(), crs.toWkt().toLatin1().constData() );
  GDALSetGeoTransform( hDstDS.get(), geoTransform );
  return hDstDS;
}

void QgsGdalUtils::resampleSingleBandRaster( GDALDatasetH hSrcDS, GDALDatasetH hDstDS, GDALResampleAlg resampleAlg )
{
  gdal::warp_options_unique_ptr psWarpOptions( GDALCreateWarpOptions() );
  psWarpOptions->hSrcDS = hSrcDS;
  psWarpOptions->hDstDS = hDstDS;

  psWarpOptions->nBandCount = 1;
  psWarpOptions->panSrcBands = ( int * ) CPLMalloc( sizeof( int ) * 1 );
  psWarpOptions->panDstBands = ( int * ) CPLMalloc( sizeof( int ) * 1 );
  psWarpOptions->panSrcBands[0] = 1;
  psWarpOptions->panDstBands[0] = 1;

  psWarpOptions->eResampleAlg = resampleAlg;

  // Establish reprojection transformer.
  psWarpOptions->pTransformerArg =
    GDALCreateGenImgProjTransformer( hSrcDS, GDALGetProjectionRef( hSrcDS ),
                                     hDstDS, GDALGetProjectionRef( hDstDS ),
                                     FALSE, 0.0, 1 );
  psWarpOptions->pfnTransformer = GDALGenImgProjTransform;

  // Initialize and execute the warp operation.
  GDALWarpOperation oOperation;
  oOperation.Initialize( psWarpOptions.get() );

  oOperation.ChunkAndWarpImage( 0, 0, GDALGetRasterXSize( hDstDS ), GDALGetRasterYSize( hDstDS ) );

  GDALDestroyGenImgProjTransformer( psWarpOptions->pTransformerArg );
}