Class: GDAL::RasterBand

Inherits:
Object
  • Object
show all
Includes:
Logger, MajorObject, AlgorithmExtensions, ColoringExtensions, Extensions, IOExtensions, GDAL::RasterBandMixins::AlgorithmMethods
Defined in:
lib/gdal/raster_band.rb,
lib/gdal/extensions/raster_band/extensions.rb,
lib/gdal/extensions/raster_band/io_extensions.rb,
lib/gdal/extensions/raster_band/coloring_extensions.rb,
lib/gdal/extensions/raster_band/algorithm_extensions.rb

Overview

rubocop:disable Metrics/ClassLength

Defined Under Namespace

Modules: AlgorithmExtensions, ColoringExtensions, Extensions, IOExtensions

Constant Summary collapse

ALL_VALID = 
0x01
PER_DATASET = 
0x02
ALPHA = 
0x04
NODATA = 
0x08

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from AlgorithmExtensions

#simple_erase!

Methods included from ColoringExtensions

#colorize!, #colors_as_hex, #colors_as_rgb, #hex_to_rgb

Methods included from IOExtensions

#block_buffer_size, #block_count, #pixel_value, #read_blocks_by_block, #read_lines_by_block, #readlines, #set_pixel_value, #write_xy_narray

Methods included from Extensions

#each_overview, #overviews, #pixel_count, #projected_points, #to_a, #to_na, #to_nna

Methods included from GDAL::RasterBandMixins::AlgorithmMethods

#checksum_image, #compute_proximity!, #fill_nodata!, included, #polygonize, #sieve_filter, #sieve_filter!

Methods included from MajorObject

#all_metadata, #description, #description=, #metadata, #metadata_domain_list, #metadata_item, #null?, #set_metadata_item

Constructor Details

#initialize(raster_band, dataset = nil) ⇒ RasterBand 



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# File 'lib/gdal/raster_band.rb', line 28

def initialize(raster_band, dataset = nil)
  @c_pointer = GDAL._pointer(GDAL::RasterBand, raster_band, autorelease: false)

  # Init the dataset too--the dataset owns the raster band, so when the dataset
  # gets closed, the raster band gets cleaned up. Storing a reference to the
  # dataset here ensures the underlying raster band doesn't get pulled out
  # from under the Ruby object that represents it.
  @dataset = dataset || init_dataset
end

Instance Attribute Details

#c_pointer ⇒ FFI::Pointer (readonly) 



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# File 'lib/gdal/raster_band.rb', line 22

def c_pointer
  @c_pointer
end

#dataset ⇒ GDAL::Dataset (readonly) 



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# File 'lib/gdal/raster_band.rb', line 25

def dataset
  @dataset
end

Instance Method Details

#access_flag ⇒ Symbol

The type of access to the raster band this object currently has.



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# File 'lib/gdal/raster_band.rb', line 62

def access_flag
  FFI::GDAL::GDAL.GDALGetRasterAccess(@c_pointer)
end

#arbitrary_overviews? ⇒ Boolean 



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# File 'lib/gdal/raster_band.rb', line 178

def arbitrary_overviews?
  !FFI::GDAL::GDAL.GDALHasArbitraryOverviews(@c_pointer).zero?
end

#block_size ⇒ Hash{x => Integer, y => Integer}

The natural block size is the block size that is most efficient for accessing the format. For many formats this is simply a whole scanline in which case x is set to #x_size, and y is set to 1.



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# File 'lib/gdal/raster_band.rb', line 122

def block_size
  x_pointer = FFI::MemoryPointer.new(:int)
  y_pointer = FFI::MemoryPointer.new(:int)
  FFI::GDAL::GDAL.GDALGetBlockSize(@c_pointer, x_pointer, y_pointer)

  { x: x_pointer.read_int, y: y_pointer.read_int }
end

#category_names ⇒ Array<String> 



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# File 'lib/gdal/raster_band.rb', line 131

def category_names
  names = FFI::GDAL::GDAL.GDALGetRasterCategoryNames(@c_pointer)
  return [] if names.null?

  names.get_array_of_string(0)
end

#category_names=(names) ⇒ Object

Raises:



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# File 'lib/gdal/raster_band.rb', line 140

def category_names=(names)
  names_pointer = GDAL._string_array_to_pointer(names)

  GDAL::CPLErrorHandler.manually_handle("Unable to set category names") do
    FFI::GDAL::GDAL.GDALSetRasterCategoryNames(@c_pointer, names_pointer)
  end
end

#color_interpretation ⇒ Symbol 



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# File 'lib/gdal/raster_band.rb', line 75

def color_interpretation
  FFI::GDAL::GDAL.GDALGetRasterColorInterpretation(@c_pointer)
end

#color_interpretation=(new_color_interp) ⇒ Object

Raises:



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# File 'lib/gdal/raster_band.rb', line 81

def color_interpretation=(new_color_interp)
  GDAL::CPLErrorHandler.manually_handle("Unable to set color interpretation") do
    FFI::GDAL::GDAL.GDALSetRasterColorInterpretation(@c_pointer, new_color_interp)
  end
end

#color_table ⇒ GDAL::ColorTable

Gets the associated GDAL::ColorTable. Note that it remains owned by the RasterBand and cannot be modified.



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# File 'lib/gdal/raster_band.rb', line 91

def color_table
  color_table_ptr = FFI::GDAL::GDAL.GDALGetRasterColorTable(@c_pointer)
  color_table_ptr.autorelease = false

  return nil if color_table_ptr.null?

  ColorTable.new(color_table_ptr)
end

#color_table=(new_color_table) ⇒ Object

Raises:



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# File 'lib/gdal/raster_band.rb', line 102

def color_table=(new_color_table)
  color_table_pointer = GDAL::ColorTable.new_pointer(new_color_table)

  GDAL::CPLErrorHandler.manually_handle("Unable to set color table") do
    FFI::GDAL::GDAL.GDALSetRasterColorTable(@c_pointer, color_table_pointer)
  end
end

#compute_statistics(approx_ok: false, &progress_block) ⇒ Hash{minimum => Float, maximum => Float, mean => Float, standard_deviation => Float} 



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# File 'lib/gdal/raster_band.rb', line 312

def compute_statistics(approx_ok: false, &progress_block)
  min_ptr = FFI::MemoryPointer.new(:double)
  max_ptr = FFI::MemoryPointer.new(:double)
  mean_ptr = FFI::MemoryPointer.new(:double)
  standard_deviation_ptr = FFI::MemoryPointer.new(:double)

  GDAL::CPLErrorHandler.manually_handle("Unable to compute raster statistics") do
    FFI::GDAL::GDAL::GDALComputeRasterStatistics(
      @c_pointer,                           # hBand
      approx_ok,                            # bApproxOK
      min_ptr,                              # pdfMin
      max_ptr,                              # pdfMax
      mean_ptr,                             # pdfMean
      standard_deviation_ptr,               # pdfStdDev
      progress_block,                       # pfnProgress
      nil                                   # pProgressData
    )
  end

  {
    minimum: min_ptr.read_double,
    maximum: max_ptr.read_double,
    mean: mean_ptr.read_double,
    standard_deviation: standard_deviation_ptr.read_double
  }
end

#copy_whole_raster(destination_band, **options, &progress) ⇒ Boolean

Copies the contents of one raster to another similarly configure band. The two bands must have the same width and height but do not have to be the same data type.

Options:

* :compressed
  * 'YES': forces alignment on the destination_band to achieve the best
    compression.

Options Hash (**options):

  • compress (String) —

    Only ‘YES’ is supported.



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# File 'lib/gdal/raster_band.rb', line 595

def copy_whole_raster(destination_band, **options, &progress)
  destination_pointer = GDAL._pointer(GDAL::RasterBand, destination_band)
  options_ptr = GDAL::Options.pointer(options)

  GDAL::CPLErrorHandler.manually_handle("Unable to copy whole raster") do
    FFI::GDAL::GDAL.GDALRasterBandCopyWholeRaster(@c_pointer,
                                                  destination_pointer,
                                                  options_ptr,
                                                  progress,
                                                  nil)
  end
end

#create_mask_band(*flags) ⇒ Object

Raises:



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# File 'lib/gdal/raster_band.rb', line 241

def create_mask_band(*flags)
  flag_value = 0

  flag_value = flags.each_with_object(flag_value) do |flag, result|
    result + case flag
             when :GMF_ALL_VALID then 0x01
             when :GMF_PER_DATASET then 0x02
             when :GMF_PER_ALPHA then 0x04
             when :GMF_NODATA then 0x08
             else 0
             end
  end

  GDAL::CPLErrorHandler.manually_handle("Unable to create mask band") do
    FFI::GDAL::GDAL.GDALCreateMaskBand(@c_pointer, flag_value)
  end
end

#data_type ⇒ Symbol

The pixel data type for this band.



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# File 'lib/gdal/raster_band.rb', line 113

def data_type
  FFI::GDAL::GDAL.GDALGetRasterDataType(@c_pointer)
end

#default_histogram(force: false, &block) {|completion, message| ... } ⇒ Hash{minimum => Float, maximum => Float, buckets => Integer, totals => Array<Integer>}

Gets the default raster histogram. Results are returned as a Hash so some metadata about the histogram can be returned. Example:

{
  :minimum => -0.9,
  :maximum => 255.9,
  :buckets => 256,
  :totals => [
    3954, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 1, 0,
    0, 0, 10, 27, 201, 699, 1766, 3472, 5013, 6464, 7698, 8352,
    9039, 10054, 11378, 13132, 14377, 14371, 14221, 14963, 14740,
    14379, 13724, 12938, 11318, 9828, 8504, 7040, 5700, 4890,
    4128, 3276, 2749, 2322, 1944, 1596, 1266, 1050, 784, 663,
    547, 518, 367, 331, 309, 279, 178, 169, 162, 149, 109, 98,
    90, 89, 82, 85, 74, 75, 42, 40, 39, 35, 39, 36, 36, 27, 20,
    12, 13, 19, 16, 12, 11, 6, 6, 8, 12, 6, 8, 11, 3, 7, 9, 2,
    5, 2, 5, 1, 4, 0, 0, 1, 0, 1, 2, 1, 0, 2, 1, 0, 0, 1, 0, 1,
    1, 1, 0, 2, 1, 2, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
  ]
}

Also, you can pass a block to get status on the processing. Conforms to FFI::GDAL::GDAL::GDALProgressFunc.

Yield Parameters:

  • completion (Float) —

    The ration completed as a decimal.

  • message (String) —

    Message string to display.



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# File 'lib/gdal/raster_band.rb', line 484

def default_histogram(force: false, &block)
  min_pointer = FFI::MemoryPointer.new(:double)
  max_pointer = FFI::MemoryPointer.new(:double)
  buckets_pointer = FFI::MemoryPointer.new(:int)
  histogram_pointer = FFI::MemoryPointer.new(:pointer)
  progress_proc = block || nil

  handler = GDAL::CPLErrorHandler.new
  handler.on_warning = proc {}
  handler.on_none = proc do
    min = min_pointer.read_double
    max = max_pointer.read_double
    buckets = buckets_pointer.read_int

    totals = if buckets.zero?
               []
             else
               histogram_pointer.get_pointer(0).read_array_of_int(buckets)
             end

    {
      minimum: min,
      maximum: max,
      buckets: buckets,
      totals: totals
    }
  end

  handler.custom_handle do
    FFI::GDAL::GDAL.GDALGetDefaultHistogram(
      @c_pointer,
      min_pointer,
      max_pointer,
      buckets_pointer,
      histogram_pointer,
      force,
      progress_proc,
      nil
    )
  end
end

#default_raster_attribute_table ⇒ GDAL::RasterAttributeTable 



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# File 'lib/gdal/raster_band.rb', line 427

def default_raster_attribute_table
  rat_pointer = FFI::GDAL::GDAL.GDALGetDefaultRAT(@c_pointer)
  return nil if rat_pointer.null?

  GDAL::RasterAttributeTable.new(rat_pointer)
end

#default_raster_attribute_table=(rat_table) ⇒ Object

Raises:



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# File 'lib/gdal/raster_band.rb', line 435

def default_raster_attribute_table=(rat_table)
  rat_table_ptr = GDAL::RasterAttributeTable.new_pointer(rat_table)

  GDAL::CPLErrorHandler.manually_handle("Unable to set default raster attribute table") do
    FFI::GDAL::GDAL.GDALSetDefaultRAT(@c_pointer, rat_table_ptr)
  end
end

#fill(real_value, imaginary_value = 0) ⇒ Object

Fill this band with constant value. Useful for clearing a band and setting to a default value.

Raises:



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# File 'lib/gdal/raster_band.rb', line 265

def fill(real_value, imaginary_value = 0)
  GDAL::CPLErrorHandler.manually_handle("Unable to fill raster") do
    FFI::GDAL::GDAL.GDALFillRaster(@c_pointer, real_value, imaginary_value)
  end
end

#flush_cache ⇒ Object

Raises:



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# File 'lib/gdal/raster_band.rb', line 39

def flush_cache
  GDAL::CPLErrorHandler.manually_handle("Unable to flush cache") do
    FFI::GDAL::GDAL.GDALFlushRasterCache(@c_pointer)
  end
end

#histogram(min, max, buckets, include_out_of_range: false, approx_ok: false, &block) {|completion, message| ... } ⇒ Hash{minimum => Float, maximum => Float, buckets => Integer, totals => Array<Integer>}

Computes a histogram using the given inputs. If you just want the default histogram, use #default_histogram.

Yield Parameters:

  • completion (Float) —

    The ration completed as a decimal.

  • message (String) —

    Message string to display.

See Also:



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# File 'lib/gdal/raster_band.rb', line 547

def histogram(min, max, buckets, include_out_of_range: false,
  approx_ok: false, &block)
  histogram_pointer = FFI::MemoryPointer.new(:pointer, buckets)
  progress_proc = block || nil

  handler = GDAL::CPLErrorHandler.new
  handler.on_warning = proc {}
  handler.on_none = proc do
    totals = if buckets.zero?
               []
             else
               histogram_pointer.read_array_of_int(buckets)
             end

    {
      minimum: min,
      maximum: max,
      buckets: buckets,
      totals: totals
    }
  end

  handler.custom_handle do
    FFI::GDAL::GDAL.GDALGetRasterHistogram(@c_pointer,
                                           min.to_f,
                                           max.to_f,
                                           buckets,
                                           histogram_pointer,
                                           include_out_of_range,
                                           approx_ok,
                                           progress_proc,
                                           nil)
  end
end

#mask_band ⇒ GDAL::RasterBand 



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# File 'lib/gdal/raster_band.rb', line 210

def mask_band
  band_pointer = FFI::GDAL::GDAL.GDALGetMaskBand(@c_pointer)
  return nil if band_pointer.null?

  self.class.new(band_pointer)
end

#mask_flags ⇒ Array<Symbol> 



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# File 'lib/gdal/raster_band.rb', line 218

def mask_flags
  flag_list = FFI::GDAL::GDAL.GDALGetMaskFlags(@c_pointer).to_s(2).scan(/\d/)
  flags = []

  flag_list.reverse_each.with_index do |flag, i|
    flag = flag.to_i

    if i.zero? && flag == 1
      flags << :GMF_ALL_VALID
    elsif i == 1 && flag == 1
      flags << :GMF_PER_DATASET
    elsif i == 2 && flag == 1
      flags << :GMF_ALPHA
    elsif i == 3 && flag == 1
      flags << :GMF_NODATA
    end
  end

  flags
end

#maximum_value ⇒ Hash{value => Float, is_tight => Boolean}

The maximum value in the band, not counting NODATA values. For file formats that don’t know this intrinsically, the maximum supported value for the data type will generally be returned.



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# File 'lib/gdal/raster_band.rb', line 750

def maximum_value
  is_tight = FFI::MemoryPointer.new(:bool)
  value = FFI::GDAL::GDAL.GDALGetRasterMaximum(@c_pointer, is_tight)

  { value: value, is_tight: is_tight.read_bytes(1).to_bool }
end

#min_max(approx_ok: false) ⇒ Hash{min => Float, max => Float}

The minimum and maximum values for this band.



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# File 'lib/gdal/raster_band.rb', line 724

def min_max(approx_ok: false)
  min_max = FFI::MemoryPointer.new(:double, 2)
  FFI::GDAL::GDAL.GDALComputeRasterMinMax(@c_pointer, approx_ok, min_max)

  { min: min_max[0].read_double, max: min_max[1].read_double }
end

#minimum_value ⇒ Hash{value => Float, is_tight => Boolean}

The minimum value in the band, not counting NODATA values. For file formats that don’t know this intrinsically, the minimum supported value for the data type will generally be returned.



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# File 'lib/gdal/raster_band.rb', line 737

def minimum_value
  is_tight = FFI::MemoryPointer.new(:bool)
  value = FFI::GDAL::GDAL.GDALGetRasterMinimum(@c_pointer, is_tight)

  { value: value, is_tight: is_tight.read_bytes(1).to_bool }
end

#no_data_value ⇒ Hash{value => Float, is_associated => Boolean}

The no data value for a band is generally a special marker value used to mark pixels that are not valid data. Such pixels should generally not be displayed, nor contribute to analysis operations.



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# File 'lib/gdal/raster_band.rb', line 153

def no_data_value
  associated = FFI::MemoryPointer.new(:bool)
  value = FFI::GDAL::GDAL.GDALGetRasterNoDataValue(@c_pointer, associated)
  value = nil if value.to_d == BigDecimal("-10_000_000_000.0")

  { value: value, is_associated: associated.read_bytes(1).to_bool }
end

#no_data_value=(value) ⇒ Object

Sets the no data value for this band. Do nothing if attempting to set to nil, because removing a no data value is impossible until GDAL 2.1.

Raises:



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# File 'lib/gdal/raster_band.rb', line 166

def no_data_value=(value)
  GDAL::CPLErrorHandler.manually_handle("Unable to set NODATA value") do
    FFI::GDAL::GDAL.GDALSetRasterNoDataValue(@c_pointer, value)
  end
end

#number ⇒ Integer

The number of band within the associated dataset that this band represents.



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# File 'lib/gdal/raster_band.rb', line 70

def number
  FFI::GDAL::GDAL.GDALGetBandNumber(@c_pointer)
end

#offset ⇒ Object

This value (in combination with the #scale value) is used to transform raw pixel values into the units returned by #units. For example this might be used to store elevations in GUInt16 bands with a precision of 0.1, and starting from -100.

Units value = (raw value * scale) + offset.

For file formats that don’t know this intrinsically a value of 0.0 is returned.



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# File 'lib/gdal/raster_band.rb', line 381

def offset
  FFI::GDAL::GDAL.GDALGetRasterOffset(@c_pointer, nil)
end

#offset=(new_offset) ⇒ Boolean

Sets the scaling offset. Very few formats support this method.



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# File 'lib/gdal/raster_band.rb', line 397

def offset=(new_offset)
  GDAL::CPLErrorHandler.manually_handle("Unable to set raster offset") do
    FFI::GDAL::GDAL.GDALSetRasterOffset(@c_pointer, new_offset)
  end
end

#offset? ⇒ Boolean

Check if the offset is set.



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# File 'lib/gdal/raster_band.rb', line 387

def offset?
  success = FFI::MemoryPointer.new(:bool)
  FFI::GDAL::GDAL.GDALGetRasterOffset(@c_pointer, success)
  success.read_bytes(1).to_bool
end

#overview(index) ⇒ GDAL::RasterBand 



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# File 'lib/gdal/raster_band.rb', line 184

def overview(index)
  return nil if overview_count.zero?

  overview_pointer = FFI::GDAL::GDAL.GDALGetOverview(@c_pointer, index)
  return nil if overview_pointer.null?

  self.class.new(overview_pointer)
end

#overview_count ⇒ Integer 



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# File 'lib/gdal/raster_band.rb', line 173

def overview_count
  FFI::GDAL::GDAL.GDALGetOverviewCount(@c_pointer)
end

#raster_io(access_flag, buffer = nil, x_size: nil, y_size: nil, x_offset: 0, y_offset: 0, buffer_x_size: nil, buffer_y_size: nil, buffer_data_type: data_type, pixel_space: 0, line_space: 0) ⇒ FFI::MemoryPointer

IO access for raster data in this band. Default values are set up to operate on one line at a time, keeping the same aspect ratio.

On buffers… You can use different size buffers from the original x and y size to allow for resampling. Using larger buffers will upsample the raster data; smaller buffers will downsample it.

On pixel_space and line_space.… These values control how data is organized in the buffer.

rubocop:disable Metrics/ParameterLists



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# File 'lib/gdal/raster_band.rb', line 651

def raster_io(access_flag, buffer = nil,
  x_size: nil, y_size: nil, x_offset: 0, y_offset: 0,
  buffer_x_size: nil, buffer_y_size: nil, buffer_data_type: data_type,
  pixel_space: 0, line_space: 0)
  return unless @c_pointer

  x_size ||= self.x_size
  y_size ||= self.y_size

  buffer_x_size ||= x_size
  buffer_y_size ||= y_size
  buffer ||= GDAL._pointer_from_data_type(buffer_data_type, buffer_x_size * buffer_y_size)

  FFI::GDAL::GDAL.GDALRasterIO(
    @c_pointer,
    GDAL._gdal_access_flag(access_flag),
    x_offset,
    y_offset,
    x_size,
    y_size,
    buffer,
    buffer_x_size,
    buffer_y_size,
    buffer_data_type,
    pixel_space,
    line_space
  )

  buffer
end

#raster_sample_overview(desired_samples = 0) ⇒ GDAL::RasterBand

Returns the most reduced overview of this RasterBand that still satisfies the deisred number of samples. Using 0 fetches the most reduced overview. If the band doesn’t have any overviews or none of the overviews have enough samples, it will return the same band.



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# File 'lib/gdal/raster_band.rb', line 202

def raster_sample_overview(desired_samples = 0)
  band_pointer = FFI::GDAL::GDAL.GDALGetRasterSampleOverview(@c_pointer, desired_samples)
  return nil if band_pointer.null?

  self.class.new(band_pointer)
end

#read_block(x_block_number, y_block_number, image_buffer = nil) ⇒ FFI::MemoryPointer

Read a block of image data, more efficiently than #read. Doesn’t resample or do data type conversion.



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# File 'lib/gdal/raster_band.rb', line 695

def read_block(x_block_number, y_block_number, image_buffer = nil)
  image_buffer ||= FFI::MemoryPointer.new(:buffer_out, block_buffer_size)

  GDAL::CPLErrorHandler.manually_handle("Unable to read block") do
    FFI::GDAL::GDAL.GDALReadBlock(@c_pointer, x_block_number, y_block_number, image_buffer)
  end

  image_buffer
end

#scale ⇒ Object

The raster value scale. This value (in combination with the #offset value) is used to transform raw pixel values into the units returned by #units. For example this might be used to store elevations in GUInt16 bands with a precision of 0.1, and starting from -100.

Units value = (raw value * scale) + offset

For file formats that don’t know this intrinsically a value of one is returned.



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# File 'lib/gdal/raster_band.rb', line 350

def scale
  FFI::GDAL::GDAL.GDALGetRasterScale(@c_pointer, nil)
end

#scale=(new_scale) ⇒ Object

Raises:



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# File 'lib/gdal/raster_band.rb', line 364

def scale=(new_scale)
  GDAL::CPLErrorHandler.manually_handle("Unable to set raster scale") do
    FFI::GDAL::GDAL.GDALSetRasterScale(@c_pointer, new_scale.to_f)
  end
end

#scale? ⇒ Boolean

Check if the scale is set.



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# File 'lib/gdal/raster_band.rb', line 356

def scale?
  success = FFI::MemoryPointer.new(:bool)
  FFI::GDAL::GDAL.GDALGetRasterScale(@c_pointer, success)
  success.read_bytes(1).to_bool
end

#statistics(approx_ok: true, force: true) ⇒ Hash{minimum: Float, maximum: Float, mean: Float, standard_deviation: Float}

Returns minimum, maximum, mean, and standard deviation of all pixel values in this band.



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# File 'lib/gdal/raster_band.rb', line 280

def statistics(approx_ok: true, force: true)
  min = FFI::MemoryPointer.new(:double)
  max = FFI::MemoryPointer.new(:double)
  mean = FFI::MemoryPointer.new(:double)
  standard_deviation = FFI::MemoryPointer.new(:double)

  handler = GDAL::CPLErrorHandler.new
  handler.on_warning = proc { {} }
  handler.on_none = proc do
    {
      minimum: min.read_double,
      maximum: max.read_double,
      mean: mean.read_double,
      standard_deviation: standard_deviation.read_double
    }
  end

  handler.custom_handle do
    FFI::GDAL::GDAL.GDALGetRasterStatistics(@c_pointer,
                                            approx_ok,
                                            force,
                                            min,
                                            max,
                                            mean,
                                            standard_deviation)
  end
end

#unit_type ⇒ String 



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# File 'lib/gdal/raster_band.rb', line 404

def unit_type
  # The returned string should not be modified, nor freed by the calling application.
  type, ptr = FFI::GDAL::GDAL.GDALGetRasterUnitType(@c_pointer)
  ptr.autorelease = false

  type
end

#unit_type=(new_unit_type) ⇒ Object

Raises:



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# File 'lib/gdal/raster_band.rb', line 415

def unit_type=(new_unit_type)
  unless defined? FFI::GDAL::GDAL::GDALSetRasterUnitType
    warn "GDALSetRasterUnitType is not defined.  Can't call RasterBand#unit_type="
    return
  end

  GDAL::CPLErrorHandler.manually_handle("Unable to set unit type") do
    FFI::GDAL::GDAL.GDALSetRasterUnitType(@c_pointer, new_unit_type)
  end
end

#write_block(x_block_number, y_block_number, data_pointer = nil) ⇒ Object 



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# File 'lib/gdal/raster_band.rb', line 711

def write_block(x_block_number, y_block_number, data_pointer = nil)
  data_pointer ||= FFI::Buffer.alloc_inout(block_buffer_size)

  GDAL::CPLErrorHandler.manually_handle("Unable to write block") do
    FFI::GDAL::GDAL.GDALWriteBlock(@c_pointer, x_block_number, y_block_number, data_pointer)
  end

  data_pointer
end

#x_size ⇒ Integer

The raster width in pixels.



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# File 'lib/gdal/raster_band.rb', line 48

def x_size
  FFI::GDAL::GDAL.GDALGetRasterBandXSize(@c_pointer)
end

#y_size ⇒ Integer

The raster height in pixels.



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# File 'lib/gdal/raster_band.rb', line 55

def y_size
  FFI::GDAL::GDAL.GDALGetRasterBandYSize(@c_pointer)
end