Module: GDAL::Dataset::AlgorithmMethods

Included in:
GDAL::Dataset
Defined in:
lib/gdal/dataset/algorithm_methods.rb

Overview

Wrappers for Warp algorithm methods defined in gdal_alg.h.

Instance Method Summary collapse

Instance Method Details

#rasterize_geometries!(band_numbers, geometries, burn_values, transformer: nil, transform_arg: nil, **options, &progress_block) ⇒ Object

Rasterizes the geometric objects geometries into this raster dataset. transformer can be nil as long as the geometries are within the georeferenced coordinates of this raster’s dataset.

Parameters:

Options Hash (**options):

  • all_touched (Boolean) —

    If true, sets all pixels touched by the line or polygons, not just those whose center is within the polygon or that are selected by Brezenham’s line algorithm. Defaults to false.

  • burn_value_from ("Z") —

    Use the Z values of the geometries.

  • merge_alg (String) —

    “REPLACE” or “ADD”. REPLACE results in overwriting of value, while ADD adds the new value to the existing raster, suitable for heatmaps for instance.



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# File 'lib/gdal/dataset/algorithm_methods.rb', line 24

def rasterize_geometries!(band_numbers, geometries, burn_values,
  transformer: nil, transform_arg: nil, **options, &progress_block)

  if geo_transform.nil? && gcp_count.zero?
    raise "Can't rasterize geometries--no geo_transform or GCPs have been defined on the dataset."
  end

  gdal_options = GDAL::Options.pointer(options)
  band_numbers = Array(band_numbers)
  geometries = Array(geometries)
  burn_values = Array(burn_values)

  band_numbers_ptr = FFI::MemoryPointer.new(:pointer, band_numbers.size)
  band_numbers_ptr.write_array_of_int(band_numbers)

  geometries_ptr = FFI::MemoryPointer.new(:pointer, geometries.size)
  geometries_ptr.write_array_of_pointer(geometries.map(&:c_pointer))

  burn_values_ptr = FFI::MemoryPointer.new(:pointer, burn_values.size)
  burn_values_ptr.write_array_of_double(burn_values)

  FFI::GDAL::Alg.GDALRasterizeGeometries(@c_pointer,
                                         band_numbers.size,
                                         band_numbers_ptr,
                                         geometries.size,
                                         geometries_ptr,
                                         transformer,
                                         transform_arg,
                                         burn_values_ptr,
                                         gdal_options,
                                         progress_block,
                                         nil)
end

#rasterize_layers!(band_numbers, layers, burn_values, transformer: nil, transform_arg: nil, **options, &progress_block) ⇒ Object

Parameters:

Options Hash (**options):

  • attribute (String) —

    An attribute field on features to be used for a burn-in value, which will be burned into all output bands.

  • chunkysize (Integer) —

    The height in lines of the chunk to operate on.

  • all_touched (Boolean) —

    If true, sets all pixels touched by the line or polygons, not just those whose center is within the polygon or that are selected by Brezenham’s line algorithm. Defaults to false.

  • burn_value_from ("Z") —

    Use the Z values of the geometries.



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# File 'lib/gdal/dataset/algorithm_methods.rb', line 75

def rasterize_layers!(band_numbers, layers, burn_values,
  transformer: nil, transform_arg: nil, **options, &progress_block)
  gdal_options = GDAL::Options.pointer(options)
  band_numbers = Array(band_numbers)
  log "band numbers: #{band_numbers}"

  layers = Array(layers)
  log "layers: #{layers}"

  burn_values = Array(burn_values)
  log "burn values: #{burn_values}"

  band_numbers_ptr = FFI::MemoryPointer.new(:pointer, band_numbers.size)
  band_numbers_ptr.write_array_of_int(band_numbers)
  log "band numbers ptr null? #{band_numbers_ptr.null?}"

  layers_ptr = FFI::MemoryPointer.new(:pointer, layers.size)
  layers_ptr.write_array_of_pointer(layers.map(&:c_pointer))
  log "layers ptr null? #{layers_ptr.null?}"

  burn_values_ptr = FFI::MemoryPointer.new(:pointer, burn_values.size)
  burn_values_ptr.write_array_of_double(burn_values)
  log "burn value ptr null? #{burn_values_ptr.null?}"

  FFI::GDAL::Alg.GDALRasterizeLayers(@c_pointer, # hDS
                                     band_numbers.size,                                # nBandCount
                                     band_numbers_ptr,                                 # panBandList
                                     layers.size,                                      # nLayerCount
                                     layers_ptr,                                       # pahLayers
                                     transformer,                                      # pfnTransformer
                                     transform_arg,                                    # pTransformerArg
                                     burn_values_ptr,                                  # padfLayerBurnValues
                                     gdal_options,                                     # papszOptions
                                     progress_block,                                   # pfnProgress
                                     nil)                                              # pProgressArg
end

#simple_image_warp(destination_dataset, transformer, transformer_arg_ptr, warp_options, band_numbers = 0, progress = nil) ⇒ GDAL::Dataset?

Returns The new dataset or nil if the warping failed.

Parameters:

  • destination_dataset (String)
  • transformer (Proc, FFI::Function)
  • transformer_arg_ptr (FFI::Pointer) —

    The pointer created from one of the GDAL::Transformers.

  • warp_options (Hash)
  • band_numbers (Integer, Array<Integer>) (defaults to: 0) —

    Raster bands to include in the warping. 0 indicates all bands.

  • progress (Proc) (defaults to: nil)

Options Hash (warp_options):

  • init (String) —

    Indicates that the output dataset should be initialized to the given value in any area where valid data isn’t written. In form: “v”

Returns:

  • (GDAL::Dataset, nil) —

    The new dataset or nil if the warping failed.



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# File 'lib/gdal/dataset/algorithm_methods.rb', line 124

def simple_image_warp(destination_dataset, transformer, transformer_arg_ptr,
  warp_options, band_numbers = 0, progress = nil)
  destination_dataset_ptr = destination_dataset.c_pointer

  band_numbers = Array(band_numbers)
  log "band numbers: #{band_numbers}"

  bands_ptr = FFI::MemoryPointer.new(:pointer, band_numbers.size)
  bands_ptr.write_array_of_int(band_numbers)
  log "band numbers ptr null? #{bands_ptr.null?}"

  success = FFI::GDAL::Alg.GDALSimpleImageWarp(@c_pointer,
                                               destination_dataset_ptr,
                                               band_numbers.size,
                                               bands_ptr,
                                               transformer,
                                               transformer_arg_ptr,
                                               progress,
                                               nil,
                                               warp_options.c_pointer)

  success ? destination_dataset : nil
end

#suggested_warp_output(transformer) ⇒ Hash{geo_transform: GDAL::GeoTransform, lines: Integer, pixels: Integer}

Parameters:

Returns:



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# File 'lib/gdal/dataset/algorithm_methods.rb', line 150

def suggested_warp_output(transformer)
  geo_transform = GDAL::GeoTransform.new
  pixels_ptr = FFI::MemoryPointer.new(:int)
  lines_ptr = FFI::MemoryPointer.new(:int)

  FFI::GDAL::Alg.GDALSuggestedWarpOutput(
    @c_pointer,
    transformer.function,
    transformer.c_pointer,
    geo_transform.c_pointer,
    pixels_ptr,
    lines_ptr
  )

  {
    geo_transform: geo_transform,
    lines: lines_ptr.read_int,
    pixels: pixels_ptr.read_int
  }
end

#suggested_warp_output2(transformer) ⇒ Hash{extents: Hash{ min_x: Integer, min_y: Integer, max_x: Integer, max_y: Integer }, geo_transform: GDAL::GeoTransform, lines: Integer, pixels: Integer}

Parameters:

Returns:



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# File 'lib/gdal/dataset/algorithm_methods.rb', line 175

def suggested_warp_output2(transformer)
  geo_transform = GDAL::GeoTransform.new
  pixels_ptr = FFI::MemoryPointer.new(:int)
  lines_ptr = FFI::MemoryPointer.new(:int)
  extents_ptr = FFI::MemoryPointer.new(:double, 4)
  options = 0 # C code says this isn't used yet.

  FFI::GDAL::Alg.GDALSuggestedWarpOutput2(
    @c_pointer,
    transformer.function,
    transformer.c_pointer,
    geo_transform.c_pointer,
    pixels_ptr,
    lines_ptr,
    extents_ptr,
    options
  )

  extents_array = extents_ptr.read_array_of_double(4)

  extents = {
    min_x: extents_array[0],
    min_y: extents_array[1],
    max_x: extents_array[2],
    max_y: extents_array[3]
  }

  {
    extents: extents,
    geo_transform: geo_transform,
    lines: lines_ptr.read_int,
    pixels: pixels_ptr.read_int
  }
end