24.2.2. Raster conversion

24.2.2.1. gdal2xyz

Converts raster data to XYZ ASCII file format.

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Raster layer to convert
Band number	BAND	[raster band] Default: The first band of the input layer	If the raster is multiband, choose the band you want to convert
Output comma-separated values	CSV	[boolean] Default: False	Sets whether the output file should be of type comma-separated values (csv).
XYZ ASCII file	OUTPUT	[file] Default: [Save to temporary file]	Specification of the output file. One of: Save to a Temporary File Save to File... The file encoding can also be changed here.

輸出

Label	名稱	Type	說明
XYZ ASCII file	INPUT	[table]	Table file containing the values exported from the raster band.

Python code

Algorithm ID: gdal:gdal2xyz

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.2.2.2. PCT to RGB

Converts an 8 bit paletted image to a 24 bit RGB. It will convert a pseudocolor band from the input file to an RGB file of the desired format.

This algorithm is derived from the GDAL pct2rgb utility.

Default menu: Raster ► Conversion

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input 8 bit raster image
Band number	BAND	[raster band] Default: The first band of the input layer	If the raster is multiband, choose the band you want to convert
Generate a RGBA file	RGBA	[boolean] Default: False	Sets whether the output file should be of type RGBA.
PCT to RGB	OUTPUT	[file] Default: [Save to temporary file]	Specification of the output file. One of: Save to a Temporary File Save to File... The file encoding can also be changed here.

輸出

Label	名稱	Type	說明
PCT to RGB	OUTPUT	[raster]	24 bit RGB raster image

Python code

Algorithm ID: gdal:pcttorgb

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.2.2.3. Polygonize (raster to vector)

Creates vector polygons for all connected regions of pixels in the raster sharing a common pixel value. Each polygon is created with an attribute indicating the pixel value of that polygon.

This algorithm is derived from the GDAL polygonize utility.

Default menu: Raster ► Conversion

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input raster layer
Band number	BAND	[raster band] Default: The first band of the input layer	If the raster is multiband, choose the band you want to use
Name of the field to create	FIELD	[string] Default: 'DN'	Specify the field name for the attributes of the connected regions.
Use 8-connectedness	EIGHT_CONNECTEDNESS	[boolean] Default: False	If not set, raster cells must have a common border to be considered connected (4-connected). If set, touching raster cells are also considered connected (8-connected).
Additional command-line parameters Optional	EXTRA	[string] Default: None	Add extra GDAL command line options
Vectorized	OUTPUT	[vector: polygon] Default: [Save to temporary file]	Specification of the output (polygon) vector layer. One of: Save to a Temporary File Save to File... The file encoding can also be changed here.

輸出

Label	名稱	Type	說明
Vectorized	OUTPUT	[vector: polygon]	Output vector layer

Python code

Algorithm ID: gdal:polygonize

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.2.2.4. Rearrange bands

Creates a new raster using selected band(s) from a given raster layer. The algorithm also makes it possible to reorder the bands for the newly-created raster.

This algorithm is derived from the GDAL translate utility.

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input raster layer
Selected band(s)	BANDS	[raster band] [list] Default: None	Ordered list of the bands to use to create the new raster
Additional creation options Optional	OPTIONS	[string] Default: ''	For adding one or more creation options that control the raster to be created (colors, block size, file compression...). For convenience, you can rely on predefined profiles (see GDAL driver options section). For Batch Process: separate multiple options with a pipe character (|).
Output data type	DATA_TYPE	[enumeration] Default: 0	Defines the data type of the output raster file. Options: 0 --- Use Input Layer Data Type 1 --- Byte 2 --- Int16 3 --- UInt16 4 --- UInt32 5 --- Int32 6 --- Float32 7 --- Float64 8 --- CInt16 9 --- CInt32 10 --- CFloat32 11 --- CFloat64
Converted	OUTPUT	[raster] Default: Save to temporary file	Specification of the output raster. One of: Save to a Temporary File Save to File... The file encoding can also be changed here.

輸出

Label	名稱	Type	說明
Converted	OUTPUT	[raster]	Output raster layer with rearranged bands.

Python code

Algorithm ID: gdal:rearrange_bands

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.2.2.5. RGB to PCT

Converts a 24 bit RGB image into a 8 bit paletted. Computes an optimal pseudo-color table for the given RGB-image using a median cut algorithm on a downsampled RGB histogram. Then it converts the image into a pseudo-colored image using the color table. This conversion utilizes Floyd-Steinberg dithering (error diffusion) to maximize output image visual quality.

If you want to classify a raster map and want to reduce the number of classes it can be helpful to downsample your image with this algorithm before.

This algorithm is derived from the GDAL rgb2pct utility.

Default menu: Raster ► Conversion

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input (RGB) raster layer
Number of colors	NCOLORS	[number] Default: 2	The number of colors the resulting image will contain. A value from 2-256 is possible.
RGB to PCT	OUTPUT	[raster] Default: [Save to temporary file]	Specification of the output raster. One of: Save to a Temporary File Save to File... The file encoding can also be changed here.

輸出

Label	名稱	Type	說明
RGB to PCT	OUTPUT	[raster]	Output raster layer.

Python code

Algorithm ID: gdal:rgbtopct

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.2.2.6. Translate (convert format)

Converts raster data between different formats.

This algorithm is derived from the GDAL translate utility.

Default menu: Raster ► Conversion

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input raster layer
Override the projection of the output file Optional	TARGET_CRS	[crs]	Specify a projection for the output file
Assign a specified nodata value to output bands Optional	NODATA	[number] Default: Not set	Defines the value to use for nodata in the output raster
Copy all subdatasets of this file to individual output files	COPY_SUBDATASETS	[boolean] Default: False	Create individual files for subdatasets
Additional creation options Optional	OPTIONS	[string] Default: ''	For adding one or more creation options that control the raster to be created (colors, block size, file compression...). For convenience, you can rely on predefined profiles (see GDAL driver options section). For Batch Process: separate multiple options with a pipe character (|).
Additional command-line parameters Optional	EXTRA	[string] Default: None	Add extra GDAL command line options
Output data type	DATA_TYPE	[enumeration] Default: 0	Defines the data type of the output raster file. Options: 0 --- Use Input Layer Data Type 1 --- Byte 2 --- Int16 3 --- UInt16 4 --- UInt32 5 --- Int32 6 --- Float32 7 --- Float64 8 --- CInt16 9 --- CInt32 10 --- CFloat32 11 --- CFloat64
Converted	OUTPUT	[raster] Default: [Save to temporary file]	Specification of the output (translated) raster layer. One of: Save to a Temporary File Save to File... The file encoding can also be changed here.

輸出

Label	名稱	Type	說明
Converted	OUTPUT	[raster]	Output (translated) raster layer.

Python code

Algorithm ID: gdal:translate

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.