28.2.2. Raster conversion
28.2.2.1. gdal2xyz
Converts raster data to XYZ ASCII file format.
Parameters
Label |
Name |
Type |
Description |
---|---|---|---|
Input layer |
|
[raster] |
Raster layer to convert |
Band number |
|
[raster band] Default: The first band of the input layer |
If the raster is multiband, choose the band you want to convert |
Source NoData Optional |
|
[number] Default: None |
Input pixel value to treat as “NoData” (GDAL >= 3.7). |
Destination NoData Optional |
|
[number] Default: None |
Assign specified “NoData” value to output (GDAL >= 3.7). |
Do not output NoData values |
|
[boolean] Default: False |
Do not output “NoData” values (GDAL >= 3.3). |
Output comma-separated values |
|
[boolean] Default: False |
Sets whether the output file should be of type comma-separated values (csv). |
XYZ ASCII file |
|
[file] Default: |
Specification of the output file. One of:
|
Outputs
Label |
Name |
Type |
Description |
---|---|---|---|
XYZ ASCII file |
|
[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.
28.2.2.2. 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:
Parameters
Label |
Name |
Type |
Description |
---|---|---|---|
Input layer |
|
[raster] |
Input 8 bit raster image |
Band number |
|
[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 |
|
[boolean] Default: False |
Sets whether the output file should be of type RGBA. |
PCT to RGB |
|
[file] Default: |
Specification of the output file. One of:
|
Outputs
Label |
Name |
Type |
Description |
---|---|---|---|
PCT to RGB |
|
[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.
28.2.2.3. 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:
Parameters
Basic parameters
Label |
Name |
Type |
Description |
---|---|---|---|
Input layer |
|
[raster] |
Input raster layer |
Band number |
|
[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 |
|
[string] Default: ‘DN’ |
Specify the field name for the attributes of the connected regions. |
Use 8-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). |
Vectorized |
|
[vector: polygon] Default: |
Specification of the output (polygon) vector layer. One of:
|
Advanced parameters
Label |
Name |
Type |
Description |
---|---|---|---|
Additional command-line parameters Optional |
|
[string] Default: None |
Add extra GDAL command line options |
Outputs
Label |
Name |
Type |
Description |
---|---|---|---|
Vectorized |
|
[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.
28.2.2.4. 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.
Parameters
Basic parameters
Label |
Name |
Type |
Description |
---|---|---|---|
Input layer |
|
[raster] |
Input raster layer |
Selected band(s) |
|
[raster band] [list] Default: None |
Ordered list of the bands to use to create the new raster |
Converted |
|
[raster] Default: |
Specification of the output raster. One of:
|
Advanced parameters
Label |
Name |
Type |
Description |
---|---|---|---|
Additional creation options Optional |
|
[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). Batch Process and Model Designer: separate multiple options with a pipe
character ( |
Output data type |
|
[enumeration] Default: 0 |
Defines the data type of the output raster file. Options:
Available options depend on the GDAL version built with QGIS (see menu) |
Outputs
Label |
Name |
Type |
Description |
---|---|---|---|
Converted |
|
[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.
28.2.2.5. 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:
Parameters
Label |
Name |
Type |
Description |
---|---|---|---|
Input layer |
|
[raster] |
Input (RGB) raster layer |
Number of colors |
|
[number] Default: 2 |
The number of colors the resulting image will contain. A value from 2-256 is possible. |
RGB to PCT |
|
[raster] Default: |
Specification of the output raster. One of:
|
Outputs
Label |
Name |
Type |
Description |
---|---|---|---|
RGB to PCT |
|
[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.
28.2.2.6. Translate (convert format)
Converts raster data between different formats.
This algorithm is derived from the GDAL translate utility.
Default menu:
Parameters
Basic parameters
Label |
Name |
Type |
Description |
---|---|---|---|
Input layer |
|
[raster] |
Input raster layer |
Override the projection of the output file Optional |
|
[crs] |
Specify a projection for the output file |
Assign a specified NoData value to output bands Optional |
|
[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 |
|
[boolean] Default: False |
Create individual files for subdatasets |
Converted |
|
[raster] Default: |
Specification of the output (translated) raster layer. One of:
|
Advanced parameters
Label |
Name |
Type |
Description |
---|---|---|---|
Additional creation options Optional |
|
[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). Batch Process and Model Designer: separate multiple options with a pipe
character ( |
Additional command-line parameters Optional |
|
[string] Default: None |
Add extra GDAL command line options |
Output data type |
|
[enumeration] Default: 0 |
Defines the data type of the output raster file. Options:
Available options depend on the GDAL version built with QGIS (see menu) |
Outputs
Label |
Name |
Type |
Description |
---|---|---|---|
Converted |
|
[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.