class GDAL::Utils::DEM

Wrapper for gdaldem using GDALDEMProcessing C API.

@see gdal.org/programs/gdaldem.html gdaldem utility documentation. @see gdal.org/api/gdal_utils.html#_CPPv417GDALDEMProcessingPKc12GDALDatasetHPKcPKcPK24GDALDEMProcessingOptionsPi

GDALDEMProcessing C API.

Public Class Methods

perform(dst_dataset_path:, src_dataset:, processing:, color_filename: nil, options: Options.new, &block) click to toggle source

Perform the gdaldem (GDALDEMProcessing) operation.

@example Create a raster dataset.

src_dataset = GDAL::Dataset.open("source.tif", "r")

dataset = GDAL::Utils::DEM.perform(
  dst_dataset_path: "destination.tif",
  src_dataset: src_dataset,
  processing: "hillshade"
)

# Do something with the dataset.
puts dataset.raster_x_size

# You must close the dataset when you are done with it.
dataset.close
src_dataset.close

@example Create a raster dataset for color-relief.

src_dataset = GDAL::Dataset.open("source.tif", "r")

dataset = GDAL::Utils::DEM.perform(
  dst_dataset_path: "destination.tif",
  src_dataset: src_dataset,
  processing: "color-relief",
  color_filename: "color.txt"
)

# Do something with the dataset.
puts dataset.raster_x_size

# You must close the dataset when you are done with it.
dataset.close
src_dataset.close

@example Create a raster dataset with options.

src_dataset = GDAL::Dataset.open("source.tif", "r")
options = GDAL::Utils::DEM::Options.new(options: ["-of", "GTiff", "-co", "TILED=YES"])

dataset = GDAL::Utils::DEM.perform(
  dst_dataset_path: "destination.tif",
  src_dataset: src_dataset,
  processing: "hillshade",
  options: options
)

# Do something with the dataset.
puts dataset.raster_x_size

# You must close the dataset when you are done with it.
dataset.close
src_dataset.close

@example Create a raster dataset using block syntax.

src_dataset = GDAL::Dataset.open("source.tif", "r")

GDAL::Utils::DEM.perform(
  dst_dataset_path: "destination.tif",
  src_dataset: src_dataset,
  processing: "hillshade"
) do |dataset|
  # Do something with the dataset.
  puts dataset.raster_x_size

  # Dataset will be closed automatically.
end
src_dataset.close

@param dst_dataset_path [String] The path to the destination dataset. @param src_dataset [OGR::DataSource] The source dataset. @param processing [String] The processing type

(one of "hillshade", "slope", "aspect", "color-relief", "TRI", "TPI", "Roughness").

@param color_filename [String] color file (mandatory for “color-relief” processing, should be NULL otherwise). @param options [GDAL::Utils::DEM::Options] Options. @yield [GDAL::Dataset] The destination dataset. @return [GDAL::Dataset] The destination dataset (only if block is not specified; dataset must be closed). @raise [GDAL::Error] If the operation fails.

# File lib/gdal/utils/dem.rb, line 90
def self.perform(dst_dataset_path:, src_dataset:, processing:, color_filename: nil, options: Options.new, &block)
  result_code_ptr = ::FFI::MemoryPointer.new(:int)
  dst_dataset_ptr = ::FFI::GDAL::Utils.GDALDEMProcessing(
    dst_dataset_path,
    src_dataset.c_pointer,
    processing,
    color_filename,
    options.c_pointer,
    result_code_ptr
  )
  success = result_code_ptr.read_int.zero?

  raise ::GDAL::Error, "GDALDEMProcessing failed." if dst_dataset_ptr.null? || !success

  ::GDAL::Dataset.open(dst_dataset_ptr, "w", &block)
end