24.1.9. Rastrová analýza

24.1.9.1. Cell statistics

Computes per-cell statistics based on input raster layers and for each cell writes the resulting statistics to an output raster. At each cell location, the output value is defined as a function of all overlaid cell values of the input rasters.

By default, a NoData cell in ANY of the input layers will result in a NoData cell in the output raster. If the Ignore NoData values option is checked, then NoData inputs will be ignored in the statistic calculation. This may result in NoData output for locations where all cells are NoData.

The Reference layer parameter specifies an existing raster layer to use as a reference when creating the output raster. The output raster will have the same extent, CRS, and pixel dimensions as this layer.

Calculation details: Input raster layers that do not match the cell size of the reference raster layer will be resampled using nearest neighbor resampling. The output raster data type will be set to the most complex data type present in the input datasets except when using the functions Mean, Standard deviation and Variance (data type is always Float32 or Float64 depending on input float type) or Count and Variety (data type is always Int32).

• Count: The count statistic will always result in the number of cells without NoData values at the current cell location.

• Median: If the number of input layers is even, the median will be calculated as the arithmetic mean of the two middle values of the ordered cell input values.

• Minority/Majority: If no unique minority or majority could be found, the result is NoData, except all input cell values are equal.

Obr. 24.8 Example with all the statistic functions. NoData cells (grey) are taken into account.

Parameters

Label	Název	Type	Popis
Input layers	INPUT	[raster] [list]	Input raster layers
Statistic	STATISTIC	[enumeration] Default: 0	Available statistics. Options: 0 — Sum 1 — Count 2 — Mean 3 — Median 4 — Standard deviation 5 — Variance 6 — Minimum 7 — Maximum 8 — Minority (least common value) 9 — Majority (most common value) 10 — Range (max - min) 11 — Variety (unique value count)
Ignore NoData values	IGNORE_NODATA	[boolean] Default: True	Calculate statistics also for all cells stacks, ignoring NoData occurrence.
Reference layer	REF_LAYER	[raster]	The reference layer to create the output layer from (extent, CRS, pixel dimensions)
Output no data value Optional	OUTPUT_NO_DATA_VALUE	[number] Default: -9999.0	Value to use for nodata in the output layer
Output layer	OUTPUT	[same as input]	Specification of the output raster. One of: Save to a Temporary File Save to File… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
CRS authority identifier	CRS_AUTHID	[crs]	The coordinate reference system of the output raster layer
Extent	EXTENT	[extent]	The spatial extent of the output raster layer
Height in pixels	HEIGHT_IN_PIXELS	[integer]	The height in pixels of the output raster layer
Output raster	OUTPUT	[raster]	Output raster layer containing the result
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer
Width in pixels	WIDTH_IN_PIXELS	[integer]	The width in pixels of the output raster layer

Python code

Algorithm ID: qgis:cellstatistics

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.

24.1.9.2. Equal to frequency

Evaluates on a cell-by-cell basis the frequency (number of times) the values of an input stack of rasters are equal to the value of a value layer. The output raster extent and resolution are defined by the input raster layer and is always of Int32 type.

If multiband rasters are used in the data raster stack, the algorithm will always perform the analysis on the first band of the rasters - use GDAL to use other bands in the analysis. The output NoData value can be set manually.

Obr. 24.9 For each cell in the output raster, the value represents the number of times that the corresponding cells in the list of rasters are the same as the value raster. NoData cells (grey) are taken into account.

Viz také

Greater than frequency, Less than frequency

Parameters

Basic parameters

Label	Název	Type	Popis
Input value raster	INPUT_VALUE_RASTER	[raster]	The input value layer serves as reference layer for the sample layers
Value raster band	INPUT_VALUE_RASTER_BAND	[raster band] Default: The first band of the raster layer	Select the band you want to use as sample
Input raster layers	INPUT_RASTERS	[raster] [list]	Raster layers to evaluate. If multiband rasters are used in the data raster stack, the algorithm will always perform the analysis on the first band of the rasters
Ignore NoData values	IGNORE_NODATA	[boolean] Default: False	If unchecked, any NoData cells in the value raster or the data layer stack will result in a NoData cell in the output raster
Output layer	OUTPUT	[same as input] Default: [Save to temporary file]	Specification of the output raster. One of: Save to a Temporary File Save to File…

Advanced parameters

Label	Název	Type	Popis
Output no data value Optional	OUTPUT_NO_DATA_VALUE	[number] Default: -9999.0	Value to use for nodata in the output layer

Outputs

Label	Název	Type	Popis
Output layer	OUTPUT	[raster]	Output raster layer containing the result
CRS authority identifier	CRS_AUTHID	[string]	The coordinate reference system of the output raster layer
Extent	EXTENT	[string]	The spatial extent of the output raster layer
Count of cells with equal value occurrences	FOUND_LOCATIONS_COUNT	[number]
Height in pixels	HEIGHT_IN_PIXELS	[number]	The number of rows in the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer
Mean frequency at valid cell locations	MEAN_FREQUENCY_PER_LOCATION	[number]
Count of value occurrences	OCCURRENCE_COUNT	[number]
Width in pixels	WIDTH_IN_PIXELS	[integer]	The number of columns in the output raster layer

Python code

Algorithm ID: native:equaltofrequency

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.

24.1.9.3. Fuzzify raster (gaussian membership)

Transforms an input raster to a fuzzified raster by assigning a membership value to each pixel, using a Gaussian membership function. Membership values range from 0 to 1. In the fuzzified raster, a value of 0 implies no membership of the defined fuzzy set, whereas a value of 1 means full membership. The gaussian membership function is defined as , where f1 is the spread and f2 the midpoint.

Obr. 24.10 Fuzzify raster example. Input raster source: Land Tirol - data.tirol.gv.at.

Viz také

Fuzzify raster (large membership) Fuzzify raster (linear membership), Fuzzify raster (near membership), Fuzzify raster (power membership), Fuzzify raster (small membership)

Parameters

Label	Název	Type	Popis
Input Raster	INPUT	[raster]	Input raster layer
Band Number	BAND	[raster band] Default: The first band of the raster layer	If the raster is multiband, choose the band that you want to fuzzify.
Function midpoint	FUZZYMIDPOINT	[number] Default: 10	Midpoint of the gaussian function
Function spread	FUZZYSPREAD	[number] Default: 0.01	Spread of the gaussian function
Fuzzified raster	OUTPUT	[same as input]	Specification of the output raster. One of: Save to a Temporary File Save to File… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Fuzzified raster	OUTPUT	[same as input]	Output raster layer containing the result
CRS authority identifier	CRS_AUTHID	[crs]	The coordinate reference system of the output raster layer
Extent	EXTENT	[extent]	The spatial extent of the output raster layer
Width in pixels	WIDTH_IN_PIXELS	[integer]	The width in pixels of the output raster layer
Height in pixels	HEIGHT_IN_PIXELS	[integer]	The height in pixels of the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer

Python code

Algorithm ID: qgis:fuzzifyrastergaussianmembership

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.

24.1.9.4. Fuzzify raster (large membership)

Transforms an input raster to a fuzzified raster by assigning a membership value to each pixel, using a Large membership function. Membership values range from 0 to 1. In the fuzzified raster, a value of 0 implies no membership of the defined fuzzy set, whereas a value of 1 means full membership. The large membership function is defined as , where f1 is the spread and f2 the midpoint.

Viz také

Fuzzify raster (gaussian membership), Fuzzify raster (linear membership), Fuzzify raster (near membership), Fuzzify raster (power membership), Fuzzify raster (small membership)

Parameters

Label	Název	Type	Popis
Input Raster	INPUT	[raster]	Input raster layer
Band Number	BAND	[raster band] Default: The first band of the raster layer	If the raster is multiband, choose the band that you want to fuzzify.
Function midpoint	FUZZYMIDPOINT	[number] Default: 50	Midpoint of the large function
Function spread	FUZZYSPREAD	[number] Default: 5	Spread of the large function
Fuzzified raster	OUTPUT	[same as input]	Specification of the output raster. One of: Save to a Temporary File Save to File… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Fuzzified raster	OUTPUT	[same as input]	Output raster layer containing the result
CRS authority identifier	CRS_AUTHID	[crs]	The coordinate reference system of the output raster layer
Extent	EXTENT	[extent]	The spatial extent of the output raster layer
Width in pixels	WIDTH_IN_PIXELS	[integer]	The width in pixels of the output raster layer
Height in pixels	HEIGHT_IN_PIXELS	[integer]	The height in pixels of the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer

Python code

Algorithm ID: qgis:fuzzifyrasterlargemembership

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.

24.1.9.5. Fuzzify raster (linear membership)

Transforms an input raster to a fuzzified raster by assigning a membership value to each pixel, using a Linear membership function. Membership values range from 0 to 1. In the fuzzified raster, a value of 0 implies no membership of the defined fuzzy set, whereas a value of 1 means full membership. The linear function is defined as , where a is the low bound and b the high bound. This equation assigns membership values using a linear transformation for pixel values between the low and high bounds. Pixels values smaller than the low bound are given 0 membership whereas pixel values greater than the high bound are given 1 membership.

Viz také

Fuzzify raster (gaussian membership), Fuzzify raster (large membership), Fuzzify raster (near membership), Fuzzify raster (power membership), Fuzzify raster (small membership)

Parameters

Label	Název	Type	Popis
Input Raster	INPUT	[raster]	Input raster layer
Band Number	BAND	[raster band] Default: The first band of the raster layer	If the raster is multiband, choose the band that you want to fuzzify.
Low fuzzy membership bound	FUZZYLOWBOUND	[number] Default: 0	Low bound of the linear function
High fuzzy membership bound	FUZZYHIGHBOUND	[number] Default: 1	High bound of the linear function
Fuzzified raster	OUTPUT	[same as input]	Specification of the output raster. One of: Save to a Temporary File Save to File… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Fuzzified raster	OUTPUT	[same as input]	Output raster layer containing the result
CRS authority identifier	CRS_AUTHID	[crs]	The coordinate reference system of the output raster layer
Extent	EXTENT	[extent]	The spatial extent of the output raster layer
Width in pixels	WIDTH_IN_PIXELS	[integer]	The width in pixels of the output raster layer
Height in pixels	HEIGHT_IN_PIXELS	[integer]	The height in pixels of the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer

Python code

Algorithm ID: qgisfuzzifyrasterlinearmembership

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.

24.1.9.6. Fuzzify raster (near membership)

Transforms an input raster to a fuzzified raster by assigning a membership value to each pixel, using a Near membership function. Membership values range from 0 to 1. In the fuzzified raster, a value of 0 implies no membership of the defined fuzzy set, whereas a value of 1 means full membership. The near membership function is defined as , where f1 is the spread and f2 the midpoint.

Viz také

Fuzzify raster (gaussian membership), Fuzzify raster (large membership), Fuzzify raster (linear membership), Fuzzify raster (power membership), Fuzzify raster (small membership)

Parameters

Label	Název	Type	Popis
Input Raster	INPUT	[raster]	Input raster layer
Band Number	BAND	[raster band] Default: The first band of the raster layer	If the raster is multiband, choose the band that you want to fuzzify.
Function midpoint	FUZZYMIDPOINT	[number] Default: 50	Midpoint of the near function
Function spread	FUZZYSPREAD	[number] Default: 0.01	Spread of the near function
Fuzzified raster	OUTPUT	[same as input]	Specification of the output raster. One of: Save to a Temporary File Save to File… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Fuzzified raster	OUTPUT	[same as input]	Output raster layer containing the result
CRS authority identifier	CRS_AUTHID	[crs]	The coordinate reference system of the output raster layer
Extent	EXTENT	[extent]	The spatial extent of the output raster layer
Width in pixels	WIDTH_IN_PIXELS	[integer]	The width in pixels of the output raster layer
Height in pixels	HEIGHT_IN_PIXELS	[integer]	The height in pixels of the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer

Python code

Algorithm ID: qgis:fuzzifyrasternearmembership

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.

24.1.9.7. Fuzzify raster (power membership)

Transforms an input raster to a fuzzified raster by assigning a membership value to each pixel, using a Power membership function. Membership values range from 0 to 1. In the fuzzified raster, a value of 0 implies no membership of the defined fuzzy set, whereas a value of 1 means full membership. The power function is defined as , where a is the low bound, b is the high bound, and f1 the exponent. This equation assigns membership values using the power transformation for pixel values between the low and high bounds. Pixels values smaller than the low bound are given 0 membership whereas pixel values greater than the high bound are given 1 membership.

Viz také

Fuzzify raster (gaussian membership), Fuzzify raster (large membership), Fuzzify raster (linear membership), Fuzzify raster (near membership), Fuzzify raster (small membership)

Parameters

Label	Název	Type	Popis
Input Raster	INPUT	[raster]	Input raster layer
Band Number	BAND	[raster band] Default: The first band of the raster layer	If the raster is multiband, choose the band that you want to fuzzify.
Low fuzzy membership bound	FUZZYLOWBOUND	[number] Default: 0	Low bound of the power function
High fuzzy membership bound	FUZZYHIGHBOUND	[number] Default: 1	High bound of the power function
High fuzzy membership bound	FUZZYEXPONENT	[number] Default: 2	Exponent of the power function
Fuzzified raster	OUTPUT	[same as input]	Specification of the output raster. One of: Save to a Temporary File Save to File… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Fuzzified raster	OUTPUT	[same as input]	Output raster layer containing the result
CRS authority identifier	CRS_AUTHID	[crs]	The coordinate reference system of the output raster layer
Extent	EXTENT	[extent]	The spatial extent of the output raster layer
Width in pixels	WIDTH_IN_PIXELS	[integer]	The width in pixels of the output raster layer
Height in pixels	HEIGHT_IN_PIXELS	[integer]	The height in pixels of the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer

Python code

Algorithm ID: qgisfuzzifyrasterpowermembership

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.

24.1.9.8. Fuzzify raster (small membership)

Transforms an input raster to a fuzzified raster by assigning a membership value to each pixel, using a Small membership function. Membership values range from 0 to 1. In the fuzzified raster, a value of 0 implies no membership of the defined fuzzy set, whereas a value of 1 means full membership. The small membership function is defined as , where f1 is the spread and f2 the midpoint.

Viz také

Fuzzify raster (gaussian membership), Fuzzify raster (large membership) Fuzzify raster (linear membership), Fuzzify raster (near membership), Fuzzify raster (power membership)

Parameters

Label	Název	Type	Popis
Input Raster	INPUT	[raster]	Input raster layer
Band Number	BAND	[raster band] Default: The first band of the raster layer	If the raster is multiband, choose the band that you want to fuzzify.
Function midpoint	FUZZYMIDPOINT	[number] Default: 50	Midpoint of the small function
Function spread	FUZZYSPREAD	[number] Default: 5	Spread of the small function
Fuzzified raster	OUTPUT	[same as input]	Specification of the output raster. One of: Save to a Temporary File Save to File… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Fuzzified raster	OUTPUT	[same as input]	Output raster layer containing the result
CRS authority identifier	CRS_AUTHID	[crs]	The coordinate reference system of the output raster layer
Extent	EXTENT	[extent]	The spatial extent of the output raster layer
Width in pixels	WIDTH_IN_PIXELS	[integer]	The width in pixels of the output raster layer
Height in pixels	HEIGHT_IN_PIXELS	[integer]	The height in pixels of the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer

Python code

Algorithm ID: qgisfuzzifyrastersmallmembership

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.

24.1.9.9. Greater than frequency

Evaluates on a cell-by-cell basis the frequency (number of times) the values of an input stack of rasters are equal to the value of a value raster. The output raster extent and resolution is defined by the input raster layer and is always of Int32 type.

If multiband rasters are used in the data raster stack, the algorithm will always perform the analysis on the first band of the rasters - use GDAL to use other bands in the analysis. The output NoData value can be set manually.

Obr. 24.11 For each cell in the output raster, the value represents the number of times that the corresponding cells in the list of rasters are greater than the value raster. NoData cells (grey) are taken into account.

Viz také

Equal to frequency, Less than frequency

Parameters

Basic parameters

Label	Název	Type	Popis
Input value raster	INPUT_VALUE_RASTER	[raster]	The input value layer serves as reference layer for the sample layers
Value raster band	INPUT_VALUE_RASTER_BAND	[raster band] Default: The first band of the raster layer	Select the band you want to use as sample
Input raster layers	INPUT_RASTERS	[raster] [list]	Raster layers to evaluate. If multiband rasters are used in the data raster stack, the algorithm will always perform the analysis on the first band of the rasters
Ignore NoData values	IGNORE_NODATA	[boolean] Default: False	If unchecked, any NoData cells in the value raster or the data layer stack will result in a NoData cell in the output raster
Output layer	OUTPUT	[same as input] Default: [Save to temporary file]	Specification of the output raster. One of: Save to a Temporary File Save to File…

Advanced parameters

Label	Název	Type	Popis
Output no data value Optional	OUTPUT_NO_DATA_VALUE	[number] Default: -9999.0	Value to use for nodata in the output layer

Outputs

Label	Název	Type	Popis
Output layer	OUTPUT	[raster]	Output raster layer containing the result
CRS authority identifier	CRS_AUTHID	[string]	The coordinate reference system of the output raster layer
Extent	EXTENT	[string]	The spatial extent of the output raster layer
Count of cells with equal value occurrences	FOUND_LOCATIONS_COUNT	[number]
Height in pixels	HEIGHT_IN_PIXELS	[number]	The number of rows in the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer
Mean frequency at valid cell locations	MEAN_FREQUENCY_PER_LOCATION	[number]
Count of value occurrences	OCCURRENCE_COUNT	[number]
Width in pixels	WIDTH_IN_PIXELS	[integer]	The number of columns in the output raster layer

Python code

Algorithm ID: native:greaterthanfrequency

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.

24.1.9.10. Highest position in raster stack

Evaluates on a cell-by-cell basis the position of the raster with the highest value in a stack of rasters. Position counts start with 1 and range to the total number of input rasters. The order of the input rasters is relevant for the algorithm. If multiple rasters feature the highest value, the first raster will be used for the position value.

If multiband rasters are used in the data raster stack, the algorithm will always perform the analysis on the first band of the rasters - use GDAL to use other bands in the analysis. Any NoData cells in the raster layer stack will result in a NoData cell in the output raster unless the „ignore NoData“ parameter is checked. The output NoData value can be set manually. The output rasters extent and resolution is defined by a reference raster layer and is always of Int32 type.

Viz také

Lowest position in raster stack

Parameters

Basic parameters

Label	Název	Type	Popis
Input raster layers	INPUT_RASTERS	[raster] [list]	List of raster layers to compare with
Reference layer	REFERENCE_LAYER	[raster]	The reference layer for the output layer creation (extent, CRS, pixel dimensions)
Ignore NoData values	IGNORE_NODATA	[boolean] Default: False	If unchecked, any NoData cells in the data layer stack will result in a NoData cell in the output raster
Output layer	OUTPUT	[raster] Default: [Save to temporary file]	Specification of the output raster containing the result. One of: Save to a Temporary File Save to File…

Advanced parameters

Label	Název	Type	Popis
Output no data value	OUTPUT_NODATA_VALUE	[number] Default: -9999.0	Value to use for nodata in the output layer

Outputs

Label	Název	Type	Popis
Output layer	OUTPUT	[raster]	Output raster layer containing the result
CRS authority identifier	CRS_AUTHID	[string]	The coordinate reference system of the output raster layer
Extent	EXTENT	[string]	The spatial extent of the output raster layer
Width in pixels	WIDTH_IN_PIXELS	[integer]	The number of columns in the output raster layer
Height in pixels	HEIGHT_IN_PIXELS	[integer]	The number of rows in the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer

Python code

Algorithm ID: native:highestpositioninrasterstack

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.

24.1.9.11. Less than frequency

Evaluates on a cell-by-cell basis the frequency (number of times) the values of an input stack of rasters are less than the value of a value raster. The output raster extent and resolution is defined by the input raster layer and is always of Int32 type.

If multiband rasters are used in the data raster stack, the algorithm will always perform the analysis on the first band of the rasters - use GDAL to use other bands in the analysis. The output NoData value can be set manually.

Obr. 24.12 For each cell in the output raster, the value represents the number of times that the corresponding cells in the list of rasters are less than the value raster. NoData cells (grey) are taken into account.

Viz také

Equal to frequency, Greater than frequency

Parameters

Basic parameters

Label	Název	Type	Popis
Input value raster	INPUT_VALUE_RASTER	[raster]	The input value layer serves as reference layer for the sample layers
Value raster band	INPUT_VALUE_RASTER_BAND	[raster band] Default: The first band of the raster layer	Select the band you want to use as sample
Input raster layers	INPUT_RASTERS	[raster] [list]	Raster layers to evaluate. If multiband rasters are used in the data raster stack, the algorithm will always perform the analysis on the first band of the rasters
Ignore NoData values	IGNORE_NODATA	[boolean] Default: False	If unchecked, any NoData cells in the value raster or the data layer stack will result in a NoData cell in the output raster
Output layer	OUTPUT	[same as input] Default: [Save to temporary file]	Specification of the output raster. One of: Save to a Temporary File Save to File…

Advanced parameters

Label	Název	Type	Popis
Output no data value Optional	OUTPUT_NO_DATA_VALUE	[number] Default: -9999.0	Value to use for nodata in the output layer

Outputs

Label	Název	Type	Popis
Output layer	OUTPUT	[raster]	Output raster layer containing the result
CRS authority identifier	CRS_AUTHID	[string]	The coordinate reference system of the output raster layer
Extent	EXTENT	[string]	The spatial extent of the output raster layer
Count of cells with equal value occurrences	FOUND_LOCATIONS_COUNT	[number]
Height in pixels	HEIGHT_IN_PIXELS	[number]	The number of rows in the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer
Mean frequency at valid cell locations	MEAN_FREQUENCY_PER_LOCATION	[number]
Count of value occurrences	OCCURRENCE_COUNT	[number]
Width in pixels	WIDTH_IN_PIXELS	[integer]	The number of columns in the output raster layer

Python code

Algorithm ID: native:lessthanfrequency

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.

24.1.9.12. Lowest position in raster stack

Evaluates on a cell-by-cell basis the position of the raster with the lowest value in a stack of rasters. Position counts start with 1 and range to the total number of input rasters. The order of the input rasters is relevant for the algorithm. If multiple rasters feature the lowest value, the first raster will be used for the position value.

If multiband rasters are used in the data raster stack, the algorithm will always perform the analysis on the first band of the rasters - use GDAL to use other bands in the analysis. Any NoData cells in the raster layer stack will result in a NoData cell in the output raster unless the „ignore NoData“ parameter is checked. The output NoData value can be set manually. The output rasters extent and resolution is defined by a reference raster layer and is always of Int32 type.

Viz také

Highest position in raster stack

Parameters

Basic parameters

Label	Název	Type	Popis
Input raster layers	INPUT_RASTERS	[raster] [list]	List of raster layers to compare with
Reference layer	REFERENCE_LAYER	[raster]	The reference layer for the output layer creation (extent, CRS, pixel dimensions)
Ignore NoData values	IGNORE_NODATA	[boolean] Default: False	If unchecked, any NoData cells in the data layer stack will result in a NoData cell in the output raster
Output layer	OUTPUT	[raster] Default: [Save to temporary file]	Specification of the output raster containing the result. One of: Save to a Temporary File Save to File…

Advanced parameters

Label	Název	Type	Popis
Output no data value	OUTPUT_NODATA_VALUE	[number] Default: -9999.0	Value to use for nodata in the output layer

Outputs

Label	Název	Type	Popis
Output layer	OUTPUT	[raster]	Output raster layer containing the result
CRS authority identifier	CRS_AUTHID	[string]	The coordinate reference system of the output raster layer
Extent	EXTENT	[string]	The spatial extent of the output raster layer
Width in pixels	WIDTH_IN_PIXELS	[integer]	The number of columns in the output raster layer
Height in pixels	HEIGHT_IN_PIXELS	[integer]	The number of rows in the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer

Python code

Algorithm ID: native:lowestpositioninrasterstack

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.

24.1.9.13. Raster boolean AND

Calculates the boolean AND for a set of input rasters. If all of the input rasters have a non-zero value for a pixel, that pixel will be set to 1 in the output raster. If any of the input rasters have 0 values for the pixel it will be set to 0 in the output raster.

The reference layer parameter specifies an existing raster layer to use as a reference when creating the output raster. The output raster will have the same extent, CRS, and pixel dimensions as this layer.

By default, a nodata pixel in ANY of the input layers will result in a nodata pixel in the output raster. If the Treat nodata values as false option is checked, then nodata inputs will be treated the same as a 0 input value.

Viz také

Raster boolean OR

Parameters

Label	Název	Type	Popis
Input layers	INPUT	[raster] [list]	List of input raster layers
Reference layer	REF_LAYER	[raster]	The reference layer to create the output layer from (extent, CRS, pixel dimensions)
Treat nodata values as false	NODATA_AS_FALSE	[boolean] Default: False	Treat nodata values in the input files as 0 when performing the operation
Output no data value	NO_DATA	[number] Default: -9999.0	Value to use for nodata in the output layer
Output data type	DATA_TYPE	[enumeration] Default: 5	Output raster data type. Options: 0 — Byte 1 — Int16 2 — UInt16 3 — UInt32 4 — Int32 5 — Float32 6 — Float64 7 — CInt16 8 — CInt32 9 — CFloat32 10 — CFloat64
Output layer	OUTPUT	[raster]	Output raster layer

Outputs

Label	Název	Type	Popis
Extent	EXTENT	[extent]	The extent of the output raster layer
CRS authority identifier	CRS_AUTHID	[crs]	The coordinate reference system of the output raster layer
Width in pixels	WIDTH_IN_PIXELS	[integer]	The width in pixels of the output raster layer
Height in pixels	HEIGHT_IN_PIXELS	[integer]	The height in pixels of the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer
NODATA pixel count	NODATA_PIXEL_COUNT	[integer]	The count of nodata pixels in the output raster layer
True pixel count	TRUE_PIXEL_COUNT	[integer]	The count of True pixels (value = 1) in the output raster layer
False pixel count	FALSE_PIXEL_COUNT	[integer]	The count of False pixels (value = 0) in the output raster layer
Output layer	OUTPUT	[raster]	Output raster layer containing the result

Python code

Algorithm ID: qgis:rasterbooleanand

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.

24.1.9.14. Raster boolean OR

Calculates the boolean OR for a set of input rasters. If all of the input rasters have a zero value for a pixel, that pixel will be set to 0 in the output raster. If any of the input rasters have 1 values for the pixel it will be set to 1 in the output raster.

The reference layer parameter specifies an existing raster layer to use as a reference when creating the output raster. The output raster will have the same extent, CRS, and pixel dimensions as this layer.

By default, a nodata pixel in ANY of the input layers will result in a nodata pixel in the output raster. If the Treat nodata values as false option is checked, then nodata inputs will be treated the same as a 0 input value.

Viz také

Raster boolean AND

Parameters

Label	Název	Type	Popis
Input layers	INPUT	[raster] [list]	List of input raster layers
Reference layer	REF_LAYER	[raster]	The reference layer to create the output layer from (extent, CRS, pixel dimensions)
Treat nodata values as false	NODATA_AS_FALSE	[boolean] Default: False	Treat nodata values in the input files as 0 when performing the operation
Output no data value	NO_DATA	[number] Default: -9999.0	Value to use for nodata in the output layer
Output data type	DATA_TYPE	[enumeration] Default: 5	Output raster data type. Options: 0 — Byte 1 — Int16 2 — UInt16 3 — UInt32 4 — Int32 5 — Float32 6 — Float64 7 — CInt16 8 — CInt32 9 — CFloat32 10 — CFloat64
Output layer	OUTPUT	[raster]	Output raster layer

Outputs

Label	Název	Type	Popis
Extent	EXTENT	[extent]	The extent of the output raster layer
CRS authority identifier	CRS_AUTHID	[crs]	The coordinate reference system of the output raster layer
Width in pixels	WIDTH_IN_PIXELS	[integer]	The width in pixels of the output raster layer
Height in pixels	HEIGHT_IN_PIXELS	[integer]	The height in pixels of the output raster layer
Total pixel count	TOTAL_PIXEL_COUNT	[integer]	The count of pixels in the output raster layer
NODATA pixel count	NODATA_PIXEL_COUNT	[integer]	The count of nodata pixels in the output raster layer
True pixel count	TRUE_PIXEL_COUNT	[integer]	The count of True pixels (value = 1) in the output raster layer
False pixel count	FALSE_PIXEL_COUNT	[integer]	The count of False pixels (value = 0) in the output raster layer
Output layer	OUTPUT	[raster]	Output raster layer containing the result

Python code

Algorithm ID: qgis:rasterbooleanor

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.

24.1.9.15. Raster calculator

Performs algebraic operations using raster layers.

The resulting layer will have its values computed according to an expression. The expression can contain numerical values, operators and references to any of the layers in the current project.

Poznámka

When using the calculator in The batch processing interface or from the QGIS Python console the files to use have to be specified. The corresponding layers are referred using the base name of the file (without the full path). For instance, if using a layer at path/to/my/rasterfile.tif, the first band of that layer will be referred as rasterfile.tif@1.

Viz také

Raster Calculator

Parameters

Label	Název	Type	Popis
Layers	GUI only		Shows the list of all raster layers loaded in the legend. These can be used to fill the expression box (double click to add). Raster layers are referred by their name and the number of the band: layer_name@band_number. For instance, the first band from a layer named DEM will be referred as DEM@1.
Operators	GUI only		Contains some calculator like buttons that can be used to fill the expression box.
Expression	EXPRESSION	[string]	Expression that will be used to calculate the output raster layer. You can use the operator buttons provided to type directly the expression in this box.
Predefined expressions	GUI only		You can use the predefined NDVI expression or you can define new expressions for calculations. The Add… button loads a defined expression (and lets you set the parameters). The Save… button lets you define a new expression.
Reference layer(s) (used for automated extent, cellsize, and CRS) Optional	LAYERS	[raster] [list]	Layer(s) that will be used to fetch extent, cell size and CRS. By choosing the layer in this box you avoid filling in all the other parameters by hand. Raster layers are referred by their name and the number of the band: layer_name@band_number. For instance, the first band from a layer named DEM will be referred as DEM@1.
Cell size (use 0 or empty to set it automatically) Optional	CELLSIZE	[number]	Cell size of the output raster layer. If the cell size is not specified, the minimum cell size of the selected reference layer(s) will be used. The cell size will be the same for the X and Y axes.
Output extent (xmin, xmax, ymin, ymax) Optional	EXTENT	[extent]	Extent of the output raster layer. If the extent is not specified, the minimum extent that covers all the selected reference layers will be used.
Output CRS Optional	CRS	[crs]	CRS of the output raster layer. If the output CRS is not specified, the CRS of the first reference layer will be used.
Output	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.

Outputs

Label	Název	Type	Popis
Output	OUTPUT	[raster]	Output raster file with the calculated values.

Python code

Algorithm ID: qgis:rastercalculator

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.

24.1.9.16. Raster layer statistics

Calculates basic statistics from the values in a given band of the raster layer. The output is loaded in the Processing ► Results viewer menu.

Parameters

Label	Název	Type	Popis
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 get statistics for.
Output	OUTPUT_HTML_FILE	[html] Default: [Save to temporary file]	Specification of the output file: Skip Output Save to a Temporary File Save to File… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Maximum value	MAX	[number]
Mean value	MEAN	[number]
Minimum value	MIN	[number]
Output	OUTPUT_HTML_FILE	[html]	The output file contains the following information: Analyzed file: path of the raster layer Minimum value: minimum value of the raster Maximum value: maximum value of the raster Range: difference between the maximum and minimum values Sum: total sum of the values Mean value: mean of the values Standard deviation: standard deviation of the values Sum of the squares: sum of the squared differences of each observation from the overall mean
Range	RANGE	[number]
Standard deviation	STD_DEV	[number]
Sum	SUM	[number]
Sum of the squares	SUM_OF_SQUARES	[number]

Python code

Algorithm ID: qgis:rasterlayerstatistics

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.

24.1.9.17. Raster layer unique values report

Returns the count and area of each unique value in a given raster layer.

Parameters

Label	Název	Type	Popis
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 get statistics for.
Unique values report	OUTPUT_HTML_FILE	[file] Default: [Save to temporary file]	Specification of the output file: Skip Output Save to a Temporary File Save to File… The file encoding can also be changed here.
Unique values table	OUTPUT_TABLE	[table] Default: [Skip output]	Specification of the table for unique values: Skip Output Create Temporary Layer Save to File… Save to GeoPackage… Save to PostGIS Table…… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
CRS authority identifier	CRS_AUTHID	[crs]
Extent	EXTENT	[extent]
Height in pixels	HEIGHT_IN_PIXELS	[number]
NODATA pixel count	NODATA_PIXEL_COUNT	[number]
Total pixel count	TOTAL_PIXEL_COUNT	[number]
Unique values report	OUTPUT_HTML_FILE	[html]	The output HTML file contains the following information: Analyzed file: the path of the raster layer Extent: xmin, ymin, xmax, ymax coordinates of the extent Projection: projection of the layer Width in pixels: number of columns and pixel width size Height in pixels: number of rows and pixel width size Total pixel count: count of all the pixels NODATA pixel count: count of pixels with NODATA value
Unique values table	OUTPUT_TABLE	[table]	A table with three columns: value: pixel value count: count of pixels with this value m2: total area in square meters of pixels with this value.
Width in pixels	WIDTH_IN_PIXELS	[number]

Python code

Algorithm ID: qgis:rasterlayeruniquevaluesreport

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.

24.1.9.18. Raster layer zonal statistics

Calculates statistics for a raster layer’s values, categorized by zones defined in another raster layer.

Viz také

Zonal statistics

Parameters

Label	Název	Type	Popis
Input Layer	INPUT	[raster]	Input raster layer
Band number	BAND	[raster band] Default: The first band of the raster layer	If the raster is multiband choose the band for which you want to calculate the statistics.
Zones layer	ZONES	[raster]	Raster layer defining zones. Zones are given by contiguous pixels having the same pixel value.
Zones band number	ZONES_BAND	[raster band] Default: The first band of the raster layer	If the raster is multiband, choose the band that defines the zones
Reference layer Optional	REF_LAYER	[enumeration] Default: 0	Raster layer used to calculate the centroids that will be used as reference when determining the zones in the output layer. One of: 0 — Input layer 1 — Zones layer
Statistics	OUTPUT_TABLE	[table]	Table with the calculated statistics

Outputs

Label	Název	Type	Popis
CRS authority identifier	CRS_AUTHID	[crs]
Extent	EXTENT	[extent]
Height in pixels	HEIGHT_IN_PIXELS	[number]
NODATA pixel count	NODATA_PIXEL_COUNT	[number]
Statistics	OUTPUT_TABLE	[table]	The output layer contains the following information for each zone: Area: the area in square raster units in the zone; Sum: the total sum of the pixel values in the zone; Count: the number of pixels in the zone; Min: the minimum pixel value in the zone; Max: the maximum pixel value in the zone; Mean: the mean of the pixel values in the zone;
Total pixel count	TOTAL_PIXEL_COUNT	[number]
Width in pixels	WIDTH_IN_PIXELS	[number]

Python code

Algorithm ID: qgis:rasterlayerzonalstats

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.

24.1.9.19. Raster surface volume

Calculates the volume under a raster surface relative to a given base level. This is mainly useful for Digital Elevation Models (DEM).

Parameters

Label	Název	Type	Popis
INPUT layer	INPUT	[raster]	Input raster, representing a surface
Band number	BAND	[raster band] Default: The first band of the raster layer	If the raster is multiband, choose the band that shall define the surface.
Base level	LEVEL	[number] Default: 0.0	Define a base or reference value. This base is used in the volume calculation according to the Method parameter (see below).
Method	METHOD	[enumeration] Default: 0	Define the method for the volume calculation given by the difference between the raster pixel value and the Base level. Options: 0 — Count Only Above Base Level: only pixels above the base level will add to the volume. 1 — Count Only Below Base Level: only pixels below the base level will add to the volume. 2 — Subtract Volumes Below Base level: pixels above the base level will add to the volume, pixels below the base level will subtract from the volume. 3 — Add Volumes Below Base level: Add the volume regardless whether the pixel is above or below the base level. This is equivalent to sum the absolute values of the difference between the pixel value and the base level.
Surface volume report	OUTPUT_HTML_FILE	[html] Default: [Save to temporary file]	Specification of the output HTML report. One of: Skip output Save to Temporary File Save to File… The file encoding can also be changed here.
Surface volume table	OUTPUT_TABLE	[table] Default: [Skip output]	Specification of the output table. One of: Skip output Create Temporary Layer (TEMPORARY_OUTPUT) Save to File… Save to Geopackage… Save to PostGIS Table… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Volume	VOLUME	[number]	The calculated volume
Area	AREA	[number]	The area in square map units
Pixel_count	PIXEL_COUNT	[number]	The total number of pixels that have been analyzed
Surface volume report	OUTPUT_HTML_FILE	[html]	The output report (containing volume, area and pixel count) in HTML format
Surface volume table	OUTPUT_TABLE	[table]	The output table (containing volume, area and pixel count)

Python code

Algorithm ID: qgis:rastersurfacevolume

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.

24.1.9.20. Reclassify by layer

Reclassifies a raster band by assigning new class values based on the ranges specified in a vector table.

Parameters

Label	Název	Type	Popis
Raster layer	INPUT_RASTER	[raster]	Raster layer to reclassify
Band number	RASTER_BAND	[raster band] Default: The first band of the raster layer	If the raster is multiband, choose the band you want to reclassify.
Layer containing class breaks	INPUT_TABLE	[vector: any]	Vector layer containing the values to use for classification.
Minimum class value field	MIN_FIELD	[tablefield: numeric]	Field with the minimum value of the range for the class.
Maximum class value field	MAX_FIELD	[tablefield: numeric]	Field with the maximum value of the range for the class.
Output value field	VALUE_FIELD	[tablefield: numeric]	Field with the value that will be assigned to the pixels that fall in the class (between the corresponding min and max values).
Output no data value	NO_DATA	[number] Default: -9999.0	Value to apply to no data values.
Range boundaries	RANGE_BOUNDARIES	[enumeration] Default: 0	Defines comparison rules for the classification. Options: 0 — min < value <= max 1 — min <= value < max 2 — min <= value <= max 3 — min < value < max
Use no data when no range matches value	NODATA_FOR_MISSING	[boolean] Default: False	Values that do not belong to a class will result in the no data value. If False, the original value is kept.
Output data type	DATA_TYPE	[enumeration] Default: 5	Defines the data type of the output raster file. Options: 0 — Byte 1 — Int16 2 — UInt16 3 — UInt32 4 — Int32 5 — Float32 6 — Float64 7 — CInt16 8 — CInt32 9 — CFloat32 10 — CFloat64
Reclassified raster	OUTPUT	[raster]	Specification of the output raster. One of: Save to a Temporary File Save to File… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Reclassified raster	OUTPUT	[raster]	Output raster layer with reclassified band values

Python code

Algorithm ID: qgis:reclassifybylayer

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.

24.1.9.21. Reclassify by table

Reclassifies a raster band by assigning new class values based on the ranges specified in a fixed table.

Parameters

Label	Název	Type	Popis
Raster layer	INPUT_RASTER	[raster]	Raster layer to reclassify
Band number	RASTER_BAND	[raster band] Default: 1	Raster band for which you want to recalculate values.
Reclassification table	TABLE	[table]	A 3-columns table to fill with the values to set the boundaries of each class (Minimum and Maximum) and the new Value to assign to the band values that fall in the class.
Output no data value	NO_DATA	[number] Default: -9999.0	Value to apply to no data values.
Range boundaries	RANGE_BOUNDARIES	[enumeration] Default: 0	Defines comparison rules for the classification. Options: 0 — min < value <= max 1 — min <= value < max 2 — min <= value <= max 3 — min < value < max
Use no data when no range matches value	NODATA_FOR_MISSING	[boolean] Default: False	Applies the no data value to band values that do not fall in any class. If False, the original value is kept.
Output data type	DATA_TYPE	[enumeration] Default: 5	Defines the format of the output raster file. Options: 0 — Byte 1 — Int16 2 — UInt16 3 — UInt32 4 — Int32 5 — Float32 6 — Float64 7 — CInt16 8 — CInt32 9 — CFloat32 10 — CFloat64
Reclassified raster	OUTPUT	[raster] Default: ‚[Save to temporary file]‘	Specification of the output raster layer. One of: Save to a Temporary File Save to File… The file encoding can also be changed here

Outputs

Label	Název	Type	Popis
Reclassified raster	OUTPUT	[raster] Default: ‚[Save to temporary file]‘	The output raster layer.

Python code

Algorithm ID: qgis:reclassifybytable

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.

24.1.9.22. Rescale raster

Rescales raster layer to a new value range, while preserving the shape (distribution) of the raster’s histogram (pixel values). Input values are mapped using a linear interpolation from the source raster’s minimum and maximum pixel values to the destination minimum and miximum pixel range.

By default the algorithm preserves the original NODATA value, but there is an option to override it.

Obr. 24.13 Rescaling values of a raster layer from [0 - 50] to [100 - 1000]

Parameters

Label	Název	Type	Popis
Input Raster	INPUT	[raster]	Raster layer to use for rescaling
Band number	Band	[raster band] Default: The first band of the input layer	If the raster is multiband, choose a band.
New minimum value	MINIMUM	[number] Default value: 0.0	Minimum pixel value to use in the rescaled layer
New maximum value	MAXIMUM	[number] Default value: 255.0	Maximum pixel value to use in the rescaled layer
New NODATA value Optional	NODATA	[number] Default value: Not set	Value to assign to the NODATA pixels. If unset, original NODATA values are preserved.
Rescaled	OUTPUT	[raster] Default: [Save to temporary file]	Specification of the output raster layer. One of: Save to a Temporary File Save to File…

Outputs

Label	Název	Type	Popis
Rescaled	OUTPUT	[raster]	Output raster layer with rescaled band values

Python code

Algorithm ID: native:rescaleraster

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.

24.1.9.23. Round raster

Rounds the cell values of a raster dataset according to the specified number of decimals.

Alternatively, a negative number of decimal places may be used to round values to powers of a base n. For example, with a Base value n of 10 and Decimal places of -1, the algorithm rounds cell values to multiples of 10, -2 rounds to multiples of 100, and so on. Arbitrary base values may be chosen, the algorithm applies the same multiplicative principle. Rounding cell values to multiples of a base n may be used to generalize raster layers.

The algorithm preserves the data type of the input raster. Therefore byte/integer rasters can only be rounded to multiples of a base n, otherwise a warning is raised and the raster gets copied as byte/integer raster.

Obr. 24.14 Rounding values of a raster

Parameters

Basic parameters

Label	Název	Type	Popis
Input raster	INPUT	[raster]	The raster to process.
Band number	BAND	[number] Default: 1	The band of the raster
Rounding direction	ROUNDING_DIRECTION	[list] Default: 1	How to choose the target rounded value. Options are: 0 - Round up 1 - Round to nearest 2 - Round down
Number of decimals places	DECIMAL_PLACES	[number] Default: 2	Number of decimals places to round to. Use negative values to round cell values to a multiple of a base n
Output raster	OUTPUT	[raster] Default: [Save to temporary file]	Specification of the output file. One of: Save to a Temporary File Save to File…

Advanced parameters

Label	Název	Type	Popis
Base n for rounding to multiples of n	BASE_N	[number] Default: 10	When the DECIMAL_PLACES parameter is negative, raster values are rounded to multiples of the base n value

Outputs

Label	Název	Type	Popis
Output raster	OUTPUT	[raster]	The output raster layer with values rounded for the selected band.

Python code

Algorithm ID: native:roundrastervalues

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.

24.1.9.24. Sample raster values

Extracts raster values at the point locations. If the raster layer is multiband, each band is sampled.

The attribute table of the resulting layer will have as many new columns as the raster layer band count.

Parameters

Label	Název	Type	Popis
Input Point Layer	INPUT	[vector: point]	Point vector layer to use for sampling
Raster Layer to sample	RASTERCOPY	[raster]	Raster layer to sample at the given point locations.
Output column prefix	COLUMN_PREFIX	[string] Default: ‚rvalue‘	Prefix for the names of the added columns.
Sampled Points Optional	OUTPUT	[vector: point] Default: [Create temporary layer]	Specify the output layer containing the sampled values. One of: Create Temporary Layer (TEMPORARY_OUTPUT) Save to File… Save to Geopackage… Save to Database Table… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Sampled Points Optional	OUTPUT	[vector: point]	The output layer containing the sampled values.

Python code

Algorithm ID: qgis:rastersampling

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.

24.1.9.25. Zonal histogram

Appends fields representing counts of each unique value from a raster layer contained within polygon features.

The output layer attribute table will have as many fields as the unique values of the raster layer that intersects the polygon(s).

Obr. 24.15 Raster layer histogram example

Parameters

Label	Název	Type	Popis
Raster layer	INPUT_RASTER	[raster]	Input raster layer.
Band number	RASTER_BAND	[raster band] Default: The first band of the input layer	If the raster is multiband, choose a band.
Vector layer containing zones	INPUT_VECTOR	[vector: polygon]	Vector polygon layer that defines the zones.
Output column prefix	COLUMN_PREFIX Optional	[string] Default: ‚HISTO_‘	Prefix for the output columns names.
Output zones	OUTPUT	[vector: polygon] Default: [Create temporary layer]	Specify the output vector polygon layer. One of: Create Temporary Layer (TEMPORARY_OUTPUT) Save to File… Save to Geopackage… Save to Database Table… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Output zones Optional	OUTPUT	[vector: polygon] Default: [Create temporary layer]	The output vector polygon layer.

Python code

Algorithm ID: qgis:zonalhistogram

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.

24.1.9.26. Zonal statistics

Calculates statistics of a raster layer for each feature of an overlapping polygon vector layer.

Prior to QGIS 3.16, the algorithm edited the layer in-place, adding the new statistics fields to it. Now, it outputs a new layer with these statistics.

Parameters

Label	Název	Type	Popis
Input layer	INPUT	[vector: polygon]	Vector polygon layer that contains the zones.
Raster layer	INPUT_RASTER	[raster]	Input raster layer.
Raster band	RASTER_BAND	[raster band] Default: The first band of the input layer	If the raster is multiband, choose a band for the statistics.
Output column prefix	COLUMN_PREFIX	[string] Default: ‚_‘	Prefix for the output columns names.
Statistics to calculate	STATISTICS	[enumeration] [list] Default: [0,1,2]	List of statistical operator for the output. Options: 0 — Count 1 — Sum 2 — Mean 3 — Median 4 — St. dev. 5 — Minimum 6 — Maximum 7 — Range 8 — Minority 9 — Majority 10 — Variety 11 — Variance
Zonal Statistics NEW in 3.16	OUTPUT	[vector: polygon] Default: [Create temporary layer]	Specify the output vector polygon layer. One of: Create Temporary Layer (TEMPORARY_OUTPUT) Save to File… Save to Geopackage… Save to Database Table… Append to Layer… The file encoding can also be changed here.

Outputs

Label	Název	Type	Popis
Zonal Statistics NEW in 3.16	OUTPUT	[vector: polygon]	The zone vector layer with added statistics.

Python code

Algorithm ID: qgis:zonalstatisticsfb

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.