24.2.1. Raster analysis

24.2.1.1. Aspect

Generates an aspect map from any GDAL-supported elevation raster. Aspect is the compass direction that a slope faces. The pixels will have a value from 0-360° measured in degrees from north indicating the azimuth. On the northern hemisphere, the north side of slopes is often shaded (small azimuth from 0°-90°), while the southern side receives more solar radiation (higher azimuth from 180°-270°).

This algorithm is derived from the GDAL DEM utility.

Default menu: Raster ► Analysis

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input elevation raster layer
Band number	BAND	[raster band] Default: 1	The number of the band to use as elevation
Return trigonometric angle instead of azimuth	TRIG_ANGLE	[boolean] Default: False	Activating the trigonometric angle results in different categories: 0° (East), 90° (North), 180° (West), 270° (South).
Return 0 for flat instead of -9999	ZERO_FLAT	[boolean] Default: False	Activating this option will insert a 0-value for the value -9999 on flat areas.
Compute edges	COMPUTE_EDGES	[boolean] Default: False	Generates edges from the elevation raster
Use Zevenbergen&Thorne formula instead of the Horn's one	ZEVENBERGEN	[boolean] Default: False	Activates Zevenbergen&Thorne formula for smooth landscapes
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
Aspect	OUTPUT	[raster] Default: [Save to temporary file]	Output 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
Aspect	OUTPUT	[raster]	Output raster with angle values in degrees

Python code

Algorithm ID: gdal:aspect

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.

24.2.1.2. Color relief

Generates a color relief map from any GDAL-supported elevation raster. Color reliefs can particularly be used to depict elevations. The Algorithm outputs a 4-band raster with values computed from the elevation and a text-based color configuration file. By default, the colors between the given elevation values are blended smoothly and the result is a nice colorized elevation raster.

This algorithm is derived from the GDAL DEM utility.

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input elevation raster layer
Band number	BAND	[raster band] Default: 1	The number of the band to use as elevation
Compute edges	COMPUTE_EDGES	[boolean] Default: False	Generates edges from the elevation raster
Color configuration file	COLOR_TABLE	[file]	A text-based color configuration file
Matching mode	MATCH_MODE	[enumeration] Default: 2	One of: 0 --- Use strict color matching 1 --- Use closest RGBA quadruples 2 --- Use smoothly blended colours
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
Color relief	OUTPUT	[raster] Default: [Save to temporary file]	Output 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
Color relief	OUTPUT	[raster]	A 4-band output raster

Python code

Algorithm ID: gdal:colorrelief

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.

24.2.1.3. Fill nodata

Fill raster regions with no data values by interpolation from edges. The values for the no-data regions are calculated by the sourrounding pixel values using inverse distance weighting. After the interpolation a smoothing of the results takes placce. Input can be any GDAL-supported raster layer. This algorithm is generally suitable for interpolating missing regions of fairly continuously varying rasters (such as elevation models for instance). It is also suitable for filling small holes and cracks in more irregularly varying images (like airphotos). It is generally not so great for interpolating a raster from sparse point data.

This algorithm is derived from the GDAL fillnodata utility.

Default menu: Raster ► Analysis

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input raster layer
Band number	BAND	[raster band] Default: 1	The band to operate on. Nodata values must be represented by the value 0.
Maximum distance (in pixels) to search out for values to interpolate	DISTANCE	[number] Default: 10	The number of pixels to search in all directions to find values to interpolate from
Number of smoothing iterations to run after the interpolation	ITERATIONS	[number] Default: 0	The number of 3x3 filter passes to run (0 or more) to smoothen the results of the interpolation.
Do not use default validity mask for the input band	NO_MASK	[boolean] Default: False	Activates the user-defined validity mask
Validity mask	MASK_LAYER	[raster]	A raster layer that defines the areas to fill.
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
Filled	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.

輸出

Label	名稱	Type	說明
Filled	OUTPUT	[raster]	Output raster

Python code

Algorithm ID: gdal:fillnodata

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.

24.2.1.4. Grid (Data metrics)

Computes some data metrics using the specified window and output grid geometry.

This algorithm is derived from the GDAL grid utility.

Default menu: Raster ► Analysis

参见

GDAL grid tutorial

參數

Label	名稱	Type	說明
Point layer	INPUT	[vector: point]	Input point vector layer
Data metric to use	METRIC	[enumeration] Default: 0	One of: 0 --- Minimum, minimum value found in grid node search ellipse 1 --- Maximum, maximum value found in grid node search ellipse 2 --- Range, a difference between the minimum and maximum values found in grid node search ellipse 3 --- Count, a number of data points found in grid node search ellipse 4 --- Average distance, an average distance between the grid node (center of the search ellipse) and all of the data points found in grid node search ellipse 5 --- Average distance between points, an average distance between the data points found in grid node search ellipse. The distance between each pair of points within ellipse is calculated and average of all distances is set as a grid node value
The first radius of search ellipse	RADIUS_1	[number] Default: 0.0	The first radius (X axis if rotation angle is 0) of the search ellipse
The second radius of search ellipse	RADIUS_2	[number] Default: 0.0	The second radius (Y axis if rotation angle is 0) of the search ellipse
Angle of search ellipse rotation in degrees (counter clockwise)	ANGLE	[number] Default: 0.0	Angle of ellipse rotation in degrees. Ellipse rotated counter clockwise.
Minimum number of data points to use	MIN_POINTS	[number] Default: 0.0	Minimum number of data points to average. If less amount of points found the grid node considered empty and will be filled with NODATA marker.
Nodata	NODATA	[number] Default: 0.0	No data marker to fill empty points
Z value from field Optional	Z_FIELD	[tablefield: numeric]	Field for the interpolation
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: 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
Interpolated (data metrics)	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output raster layer with interpolated values. 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
Interpolated (data metrics)	OUTPUT	[raster]	Output raster with interpolated values

Python code

Algorithm ID: gdal:griddatametrics

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.

24.2.1.5. Grid (IDW with nearest neighbor searching)

Computes the Inverse Distance to a Power gridding combined to the nearest neighbor method. Ideal when a maximum number of data points to use is required.

This algorithm is derived from the GDAL grid utility.

参见

GDAL grid tutorial

參數

Label	名稱	Type	說明
Point layer	INPUT	[vector: point]	Input point vector layer
Weighting power	POWER	[number] Default: 2.0	Weighting power
Smoothing	SMOOTHING	[number] Default: 0.0	Smoothing parameter
The radius of the search circle	RADIUS	[number] Default: 1.0	The radius of the search circle
Maximum number of data points to use	MAX_POINTS	[number] Default: 12	Do not search for more points than this number.
Minimum number of data points to use	MIN_POINTS	[number] Default: 0	Minimum number of data points to average. If less amount of points found the grid node considered empty and will be filled with NODATA marker.
Nodata	NODATA	[number] Default: 0.0	No data marker to fill empty points
Z value from field Optional	Z_FIELD	[tablefield: numeric]	Field for the interpolation
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: 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
Interpolated (IDW with NN search)	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output raster layer with interpolated values. 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
Interpolated (IDW with NN search)	OUTPUT	[raster]	Output raster with interpolated values

Python code

Algorithm ID: gdal:gridinversedistancenearestneighbor

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.

24.2.1.6. Grid (Inverse distance to a power)

The Inverse Distance to a Power gridding method is a weighted average interpolator.

You should supply the input arrays with the scattered data values including coordinates of every data point and output grid geometry. The function will compute interpolated value for the given position in output grid.

This algorithm is derived from the GDAL grid utility.

Default menu: Raster ► Analysis

参见

GDAL grid tutorial

參數

Label	名稱	Type	說明
Point layer	INPUT	[vector: point]	Input point vector layer
Weighting power	POWER	[number] Default: 2.0	Weighting power
Smothing	SMOOTHING	[number] Default: 0.0	Smoothing parameter
The first radius of search ellipse	RADIUS_1	[number] Default: 0.0	The first radius (X axis if rotation angle is 0) of the search ellipse
The second radius of search ellipse	RADIUS_2	[number] Default: 0.0	The second radius (Y axis if rotation angle is 0) of the search ellipse
Angle of search ellipse rotation in degrees (counter clockwise)	ANGLE	[number] Default: 0.0	Angle of ellipse rotation in degrees. Ellipse rotated counter clockwise.
Maximum number of data points to use	MAX_POINTS	[number] Default: 0	Do not search for more points than this number.
Minimum number of data points to use	MIN_POINTS	[number] Default: 0	Minimum number of data points to average. If less amount of points found the grid node considered empty and will be filled with NODATA marker.
Nodata	NODATA	[number] Default: 0.0	No data marker to fill empty points
Z value from field Optional	Z_FIELD	[tablefield: numeric]	Field for the interpolation
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: 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
Interpolated (IDW)	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output raster layer with interpolated values. 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
Interpolated (IDW)	OUTPUT	[raster]	Output raster with interpolated values

Python code

Algorithm ID: gdal:gridinversedistance

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.

24.2.1.7. Grid (Linear)

The Linear method perform linear interpolation by computing a Delaunay triangulation of the point cloud, finding in which triangle of the triangulation the point is, and by doing linear interpolation from its barycentric coordinates within the triangle. If the point is not in any triangle, depending on the radius, the algorithm will use the value of the nearest point or the NODATA value.

This algorithm is derived from the GDAL grid utility.

參數

Label	名稱	Type	說明
Point layer	INPUT	[vector: point]	Input point vector layer
Search distance	RADIUS	[number] Default: -1.0	In case the point to be interpolated does not fit into a triangle of the Delaunay triangulation, use that maximum distance to search a nearest neighbour, or use nodata otherwise. If set to -1, the search distance is infinite. If set to 0, no data value will be used.
Nodata	NODATA	[number] Default: 0.0	No data marker to fill empty points
Z value from field Optional	Z_FIELD	[tablefield: numeric]	Field for the interpolation
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: 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
Interpolated (Linear)	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output raster layer with interpolated values. 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
Interpolated (Linear)	OUTPUT	[raster]	Output raster with interpolated values

Python code

Algorithm ID: gdal:gridlinear

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.

24.2.1.8. Grid (Moving average)

The Moving Average is a simple data averaging algorithm. It uses a moving window of elliptic form to search values and averages all data points within the window. Search ellipse can be rotated by specified angle, the center of ellipse located at the grid node. Also the minimum number of data points to average can be set, if there are not enough points in window, the grid node considered empty and will be filled with specified NODATA value.

This algorithm is derived from the GDAL grid utility.

Default menu: Raster ► Analysis

参见

GDAL grid tutorial

參數

Label	名稱	Type	說明
Point layer	INPUT	[vector: point]	Input point vector layer
The first radius of search ellipse	RADIUS_1	[number] Default: 0.0	The first radius (X axis if rotation angle is 0) of the search ellipse
The second radius of search ellipse	RADIUS_2	[number] Default: 0.0	The second radius (Y axis if rotation angle is 0) of the search ellipse
Angle of search ellipse rotation in degrees (counter clockwise)	ANGLE	[number] Default: 0.0	Angle of ellipse rotation in degrees. Ellipse rotated counter clockwise.
Minimum number of data points to use	MIN_POINTS	[number] Default: 0.0	Minimum number of data points to average. If less amount of points found the grid node considered empty and will be filled with NODATA marker.
Nodata	NODATA	[number] Default: 0.0	No data marker to fill empty points
Z value from field Optional	Z_FIELD	[tablefield: numeric]	Field for the interpolation
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: 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
Interpolated (moving average)	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output 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
Interpolated (moving average)	OUTPUT	[raster]	Output raster with interpolated values

Python code

Algorithm ID: gdal:gridaverage

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.

24.2.1.9. Grid (Nearest neighbor)

The Nearest Neighbor method doesn't perform any interpolation or smoothing, it just takes the value of nearest point found in grid node search ellipse and returns it as a result. If there are no points found, the specified NODATA value will be returned.

This algorithm is derived from the GDAL grid utility.

Default menu: Raster ► Analysis

参见

GDAL grid tutorial

參數

Label	名稱	Type	說明
Point layer	INPUT	[vector: point]	Input point vector layer
The first radius of search ellipse	RADIUS_1	[number] Default: 0.0	The first radius (X axis if rotation angle is 0) of the search ellipse
The second radius of search ellipse	RADIUS_2	[number] Default: 0.0	The second radius (Y axis if rotation angle is 0) of the search ellipse
Angle of search ellipse rotation in degrees (counter clockwise)	ANGLE	[number] Default: 0.0	Angle of ellipse rotation in degrees. Ellipse rotated counter clockwise.
Nodata	NODATA	[number] Default: 0.0	No data marker to fill empty points
Z value from field Optional	Z_FIELD	[tablefield: numeric]	Field for the interpolation
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: 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
Interpolated (Nearest neighbour)	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output raster layer with interpolated values. 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
Interpolated (Nearest neighbour)	OUTPUT	[raster]	Output raster with interpolated values

Python code

Algorithm ID: gdal:gridnearestneighbor

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.

24.2.1.10. Hillshade

Outputs a raster with a nice shaded relief effect. It’s very useful for visualizing the terrain. You can optionally specify the azimuth and altitude of the light source, a vertical exaggeration factor and a scaling factor to account for differences between vertical and horizontal units.

This algorithm is derived from the GDAL DEM utility .

Default menu: Raster ► Analysis

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input Elevation raster layer
Band number	BAND	[raster band] Default: 1	Band containing the elevation information
Z factor (vertical exaggeration)	Z_FACTOR	[number] Default: 1.0	The factor exaggerates the height of the output elevation raster
Scale (ratio of vert. units to horiz.)	SCALE	[number] Default: 1.0	The ratio of vertical units to horizontal units
Azimuth of the light	AZIMUTH	[number] Default: 315.0	Defines the azimuth of the light shining on the elevation raster in degrees. If it comes from the top of the raster the value is 0, if it comes from the east it is 90 a.s.o.
Altitude of the light	ALTITUDE	[number] Default: 45.0	Defines the altitude of the light, in degrees. 90 if the light comes from above the elevation raster, 0 if it is raking light.
Compute edges	COMPUTE_EDGES	[boolean] Default: False	Generates edges from the elevation raster
Use Zevenbergen&Thorne formula (instead of the Horn's one)	ZEVENBERGEN	[boolean] Default: False	Activates Zevenbergen&Thorne formula for smooth landscapes
Combined shading	COMBINED	[boolean] Default: False
Multidirectional shading	MULTIDIRECTIONAL	[boolean] Default: False
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
Hillshade	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output raster layer with interpolated values. 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
Hillshade	OUTPUT	[raster]	Output raster with interpolated values

Python code

Algorithm ID: gdal:hillshade

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.

24.2.1.11. Near black

Converts nearly black/white borders to black.

This algorithm will scan an image and try to set all pixels that are nearly or exactly black, white or one or more custom colors around the collar to black or white. This is often used to "fix up" lossy compressed airphotos so that color pixels can be treated as transparent when mosaicking.

This algorithm is derived from the GDAL nearblack utility.

Default menu: Raster ► Analysis

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input Elevation raster layer
How far from black (white)	NEAR	[number] Default: 15	Select how far from black, white or custom colors the pixel values can be and still considered near black, white or custom color.
Search for nearly white pixels instead of nearly black	WHITE	[boolean] Default: False	Search for nearly white (255) pixels instead of nearly black pixels
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
Nearblack	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output 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
Nearblack	OUTPUT	[raster]	Output raster

Python code

Algorithm ID: gdal:nearblack

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.

24.2.1.12. Proximity (raster distance)

Generates a raster proximity map indicating the distance from the center of each pixel to the center of the nearest pixel identified as a target pixel. Target pixels are those in the source raster for which the raster pixel value is in the set of target pixel values.

This algorithm is derived from the GDAL proximity utility.

Default menu: Raster ► Analysis

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input Elevation raster layer
Band number	BAND	[raster band] Default: 1	Band containing the elevation information
A list of pixel values in the source image to be considered target pixels Optional	VALUES	[string] Default: ''	A list of target pixel values in the source image to be considered target pixels. If not specified, all non-zero pixels will be considered target pixels.
Distance units	UNITS	[enumeration] Default: 1	Indicate whether distances generated should be in pixel or georeferenced coordinates. One of: 0 --- Georeferenced coordinates 1 --- Pixel coordinates
The maximum distance to be generated Optional	MAX_DISTANCE	[number] Default: 0.0	The maximum distance to be generated. The nodata value will be used for pixels beyond this distance. If a nodata value is not provided, the output band will be queried for its nodata value. If the output band does not have a nodata value, then the value 65535 will be used. Distance is interpreted according to the value of Distance units.
Value to be applied to all pixels that are within the maxdist of target pixels Optional	REPLACE	[number] Default: 0.0	Specify a value to be applied to all pixels that are closer than the maximum distance from target pixels (including the target pixels) instead of a distance value.
Nodata value to use for the destination proximity raster Optional	NODATA	[number] Default: 0.0	Specify the nodata value to use for the output 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 (|).
Additional command-line parameters Optional	EXTRA	[string] Default: None	Add extra GDAL command line options
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
Proximity map	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output 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
Proximity map	OUTPUT	[raster]	Output raster

Python code

Algorithm ID: gdal:proximity

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.

24.2.1.13. Roughness

Outputs a single-band raster with values computed from the elevation. Roughness is the degree of irregularity of the surface. It's calculated by the largest inter-cell difference of a central pixel and its surrounding cell. The determination of the roughness plays a role in the analysis of terrain elevation data, it's useful for calculations of the river morphology, in climatology and physical geography in general.

This algorithm is derived from the GDAL DEM utility.

Default menu: Raster ► Analysis

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input elevation raster layer
Band number	BAND	[raster band] Default: 1	The number of the band to use as elevation
Compute edges	COMPUTE_EDGES	[boolean] Default: False	Generates edges from the elevation 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 (|).
Roughness	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output 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
Roughness	OUTPUT	[raster]	Single-band output roughness raster. The value -9999 is used as nodata value.

Python code

Algorithm ID: gdal:roughness

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.

24.2.1.14. Sieve

Removes raster polygons smaller than a provided threshold size (in pixels) and replaces them with the pixel value of the largest neighbour polygon. It is useful if you have a large amount of small areas on your raster map.

This algorithm is derived from the GDAL sieve utility.

Default menu: Raster ► Analysis

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input elevation raster layer
Threshold	THRESHOLD	[number] Default: 10	Only raster polygons smaller than this size will be removed
Use 8-connectedness	EIGHT_CONNECTEDNESS	[boolean] Default: False	Use eight connectedness instead of four connectedness
Do not use the default validity mask for the input band	NO_MASK	[boolean] Default: False
Validity mask Optional	MASK_LAYER	[raster]	Validity mask to use instead of the default
Additional command-line parameters Optional	EXTRA	[string] Default: None	Add extra GDAL command line options
Sieved	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output 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
Sieved	OUTPUT	[raster]	Output raster layer.

Python code

Algorithm ID: gdal:sieve

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.

24.2.1.15. Slope

Generates a slope map from any GDAL-supported elevation raster. Slope is the angle of inclination to the horizontal. You have the option of specifying the type of slope value you want: degrees or percent slope.

This algorithm is derived from the GDAL DEM utility.

Default menu: Raster ► Analysis

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input Elevation raster layer
Band number	BAND	[raster band] Default: 1	Band containing the elevation information
Ratio of vertical units to horizontal	SCALE	[number] Default: 1.0	The ratio of vertical units to horizontal units
Slope expressed as percent (instead of degrees)	AS_PERCENT	[boolean] Default: False	Express slope as percent instead of degrees
Compute edges	COMPUTE_EDGES	[boolean] Default: False	Generates edges from the elevation raster
Use Zevenbergen&Thorne formula (instead of the Horn's one)	ZEVENBERGEN	[boolean] Default: False	Activates Zevenbergen&Thorne formula for smooth landscapes
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
Slope	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output 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
Slope	OUTPUT	[raster]	Output raster

Python code

Algorithm ID: gdal:slope

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.

24.2.1.16. Terrain Ruggedness Index (TRI)

Outputs a single-band raster with values computed from the elevation. TRI stands for Terrain Ruggedness Index, which is defined as the mean difference between a central pixel and its surrounding cells.

This algorithm is derived from the GDAL DEM utility.

Default menu: Raster ► Analysis

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input elevation raster layer
Band number	BAND	[raster band] Default: 1	The number of the band to use as elevation
Compute edges	COMPUTE_EDGES	[boolean] Default: False	Generates edges from the elevation 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 (|).
Terrain Ruggedness Index	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output 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
Terrain Ruggedness Index	OUTPUT	[raster]	Output ruggedness raster. The value -9999 is used as nodata value.

Python code

Algorithm ID: gdal:triterrainruggednessindex

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.

24.2.1.17. Topographic Position Index (TPI)

Outputs a single-band raster with values computed from the elevation. TPI stands for Topographic Position Index, which is defined as the difference between a central pixel and the mean of its surrounding cells.

This algorithm is derived from the GDAL DEM utility.

Default menu: Raster ► Analysis

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input elevation raster layer
Band number	BAND	[raster band] Default: 1	The number of the band to use for elevation values
Compute edges	COMPUTE_EDGES	[boolean] Default: False	Generates edges from the elevation 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 (|).
Terrain Ruggedness Index	OUTPUT	[raster] Default: [Save to temporary file]	Specify the output 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
Terrain Ruggedness Index	OUTPUT	[raster]	Output raster.

Python code

Algorithm ID: gdal:tpitopographicpositionindex

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.