Projections/VectorDataExtractROIExample.cxx

/*
 * Copyright (C) 2005-2022 Centre National d'Etudes Spatiales (CNES)
 *
 * This file is part of Orfeo Toolbox
 *
 *     https://www.orfeo-toolbox.org/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
 
// There is some vector data sets widely available on the internet. These data
// sets can be huge, covering an entire country, with hundreds of thousands
// objects.
//
// Most of the time, you won't be interested in the whole area and would like
// to focus only on the area corresponding to your satellite image.
//
// The \doxygen{otb}{VectorDataExtractROI} is able to extract the area corresponding
// to your satellite image, even if the image is still in sensor geometry (provided
// the sensor model is supported by OTB). Let's see how we can do that.
//
// This example demonstrates the use of the
// \doxygen{otb}{VectorDataExtractROI}.
 
#include "otbVectorData.h"
#include "otbVectorDataExtractROI.h"
 
#include "otbVectorDataFileReader.h"
#include "otbVectorDataFileWriter.h"
 
#include "otbImage.h"
#include "otbImageFileReader.h"
 
int main(int argc, char* argv[])
{
  if (argc < 4)
  {
    std::cout << argv[0] << " <input vector filename> <input image name> <output vector filename>  " << std::endl;
 
    return EXIT_FAILURE;
  }
 
  const char* inVectorName  = argv[1];
  const char* inImageName   = argv[2];
  const char* outVectorName = argv[3];
 
  using Type           = double;
  using VectorDataType = otb::VectorData<>;
 
  using VectorDataFileReaderType = otb::VectorDataFileReader<VectorDataType>;
  using VectorDataWriterType     = otb::VectorDataFileWriter<VectorDataType>;
 
  using TypedRegion = otb::RemoteSensingRegion<Type>;
 
  using ImageType                      = otb::Image<unsigned char, 2>;
  using ImageReaderType                = otb::ImageFileReader<ImageType>;
  ImageReaderType::Pointer imageReader = ImageReaderType::New();
  imageReader->SetFileName(inImageName);
  imageReader->UpdateOutputInformation();
 
  // After the usual declaration (you can check the source file for the details),
  // we can declare the \doxygen{otb}{VectorDataExtractROI}:
 
  using FilterType           = otb::VectorDataExtractROI<VectorDataType>;
  FilterType::Pointer filter = FilterType::New();
 
  // Then, we need to specify the region to extract. This region is a bit special as
  // it contains also information related to its reference system (cartographic projection
  // or sensor model projection). We retrieve all these information from the image
  // we gave as an input.
 
  TypedRegion            region;
  TypedRegion::SizeType  size;
  TypedRegion::IndexType index;
 
  size[0]  = imageReader->GetOutput()->GetLargestPossibleRegion().GetSize()[0] * imageReader->GetOutput()->GetSignedSpacing()[0];
  size[1]  = imageReader->GetOutput()->GetLargestPossibleRegion().GetSize()[1] * imageReader->GetOutput()->GetSignedSpacing()[1];
  index[0] = imageReader->GetOutput()->GetOrigin()[0] - 0.5 * imageReader->GetOutput()->GetSignedSpacing()[0];
  index[1] = imageReader->GetOutput()->GetOrigin()[1] - 0.5 * imageReader->GetOutput()->GetSignedSpacing()[1];
  region.SetSize(size);
  region.SetOrigin(index);
 
  region.SetRegionProjection(imageReader->GetOutput()->GetProjectionRef());
 
  region.SetImageMetadata(imageReader->GetOutput()->GetImageMetadata());
 
  filter->SetRegion(region);
 
  VectorDataFileReaderType::Pointer reader = VectorDataFileReaderType::New();
  VectorDataWriterType::Pointer     writer = VectorDataWriterType::New();
  reader->SetFileName(inVectorName);
  writer->SetFileName(outVectorName);
 
  // And finally, we can plug the filter in the pipeline:
 
  filter->SetInput(reader->GetOutput());
  writer->SetInput(filter->GetOutput());
 
  writer->Update();
 
  return EXIT_SUCCESS;
}