24.2.3. Raster extraction

24.2.3.1. Clip raster by extent

Clips any GDAL-supported raster file to a given extent.

This algorithm is derived from the GDAL warp utility.

Default menu: Raster ► Extraction

Parâmetros

Label

Nome

Type

Descrição

Input layer

INPUT

[raster]

The input raster

Clipping extent

EXTENT

[extent]

Extent that should be used for the output raster. Only pixels within the specified bounding box will be included in the output.

Assign a specified nodata value to output bands

Opcional

NODATA

[number]

Default: None

Defines a value that should be inserted for the nodata values in the output raster

Additional creation options

Opcional

OPTIONS

[string]

Default: “”

For adding one or more creation options that control the raster to be created (colors, block size, file compression…). For convenience, you can rely on predefined profiles (see GDAL driver options section).

For Batch Process: separate multiple options with a pipe character (|).

Output data type

DATA_TYPE

[enumeration]

Default: 0

Defines the format of the output raster file.

Options:

  • 0 — Use Input Layer Data Type

  • 1 — Byte

  • 2 — Int16

  • 3 — UInt16

  • 4 — UInt32

  • 5 — Int32

  • 6 — Float32

  • 7 — Float64

  • 8 — CInt16

  • 9 — CInt32

  • 10 — CFloat32

  • 11 — CFloat64

Additional command-line parameters

Opcional

EXTRA

[string]

Default: None

Add extra GDAL command line options

Clipped (extent)

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

Resultados

Label

Nome

Type

Descrição

Clipped (extent)

OUTPUT

[raster]

Output raster layer clipped by the given extent

Python code

Algorithm ID: gdal:cliprasterbyextent

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 Usando os algoritmos do processamento a partir da consola for details on how to run processing algorithms from the Python console.

24.2.3.2. Clip raster by mask layer

Clips any GDAL-supported raster by a vector mask layer.

This algorithm is derived from the GDAL warp utility.

Default menu: Raster ► Extraction

Parâmetros

Label

Nome

Type

Descrição

Input layer

INPUT

[raster]

The input raster

Mask layer

MASK

[vector: polygon]

Vector mask for clipping the raster

Source CRS

SOURCE_CRS

[crs]

Set the coordinate reference to use for the input raster

Target CRS

TARGET_CRS

[crs]

Set the coordinate reference to use for the mask layer

Assign a specified nodata value to output bands

Opcional

NODATA

[number]

Default: None

Defines a value that should be inserted for the nodata values in the output raster

Create an output alpha band

ALPHA_BAND

[boolean]

Default: False

Creates an alpha band for the result. The alpha band then includes the transparency values of the pixels.

Match the extent of the clipped raster to the extent of the mask layer

CROP_TO_CUTLINE

[boolean]

Default: True

Applies the vector layer extent to the output raster if checked.

Keep resolution of input raster

KEEP_RESOLUTION

[boolean]

Default: False

The resolution of the output raster will not be changed

Set output file resolution

SET_RESOLUTION

[boolean]

Default: False

Shall the output resolution (cell size) be specified

X Resolution to output bands

Opcional

X_RESOLUTION

[number]

Default: None

The width of the cells in the output raster

Y Resolution to output band

Opcional

Y_RESOLUTION

[number]

Default: None

The height of the cells in the output raster

Use multithreaded warping implementation

MULTITHREADING

[boolean]

Default: False

Two threads will be used to process chunks of image and perform input/output operation simultaneously. Note that computation is not multithreaded itself.

Additional creation options

Opcional

OPTIONS

[string]

Default: “”

For adding one or more creation options that control the raster to be created (colors, block size, file compression…). For convenience, you can rely on predefined profiles (see GDAL driver options section).

For Batch Process: separate multiple options with a pipe character (|).

Output data type

DATA_TYPE

[enumeration]

Default: 0

Defines the format of the output raster file.

Options:

  • 0 — Use Input Layer Data Type

  • 1 — Byte

  • 2 — Int16

  • 3 — UInt16

  • 4 — UInt32

  • 5 — Int32

  • 6 — Float32

  • 7 — Float64

  • 8 — CInt16

  • 9 — CInt32

  • 10 — CFloat32

  • 11 — CFloat64

Additional command-line parameters

Opcional

EXTRA

[string]

Default: None

Add extra GDAL command line options

Clipped (mask)

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

Resultados

Label

Nome

Type

Descrição

Clipped (mask)

OUTPUT

[raster]

Output raster layer clipped by the vector layer

Python code

Algorithm ID: gdal:cliprasterbymasklayer

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 Usando os algoritmos do processamento a partir da consola for details on how to run processing algorithms from the Python console.

24.2.3.3. Contour

Extracts contour lines from any GDAL-supported elevation raster.

This algorithm is derived from the GDAL contour utility.

Default menu: Raster ► Extraction

Parâmetros

Label

Nome

Type

Descrição

Input layer

INPUT

[raster]

Input raster

Band number

BAND

[raster band]

Default: 1

Raster band to create the contours from

Interval between contour lines

INTERVAL

[number]

Default: 10.0

Defines the interval between the contour lines in the given units of the elevation raster (minimum value 0)

Attribute name (if not set, no elevation attribute is attached)

Opcional

FIELD_NAME

[string]

Default: “ELEV”

Provides a name for the attribute in which to put the elevation.

Offset from zero relative to which to interpret intervals

Opcional

OFFSET

[number]

Default: 0.0

Produce 3D vector

CREATE_3D

[boolean]

Default: False

Forces production of 3D vectors instead of 2D. Includes elevation at every vertex.

Treat all raster values as valid

IGNORE_NODATA

[boolean]

Default: False

Ignores any nodata values in the dataset.

Input pixel value to treat as «nodata»

Opcional

NODATA

[number]

Default: None

Defines a value that should be inserted for the nodata values in the output raster

Additional command-line parameters

Opcional

EXTRA

[string]

Default: None

Add extra GDAL command line options. Refer to the corresponding GDAL utility documentation.

Contours

OUTPUT

[vector: line]

Default: “[Save to temporary file]”

Specification of the output vector layer. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here.

Resultados

Label

Nome

Type

Descrição

Contours

OUTPUT

[vector: line]

Output vector layer with contour lines

Python code

Algorithm ID: gdal:contour

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 Usando os algoritmos do processamento a partir da consola for details on how to run processing algorithms from the Python console.

24.2.3.4. Contour Polygons

Extracts contour polygons from any GDAL-supported elevation raster.

This algorithm is derived from the GDAL contour utility.

Parâmetros

Label

Nome

Type

Descrição

Input layer

INPUT

[raster]

Input raster

Band number

BAND

[raster band]

Default: 1

Raster band to create the contours from

Interval between contour lines

INTERVAL

[number]

Default: 10.0

Defines the interval between the contour lines in the given units of the elevation raster (minimum value 0)

Offset from zero relative to which to interpret intervals

Opcional

OFFSET

[number]

Default: 0.0

Attribute name for minimum elevation of contour polygon

Opcional

FIELD_NAME_MIN

[string]

Default: “ELEV_MIN”

Provides a name for the attribute in which to put the minimum elevation of contour polygon. If not provided no minimum elevation attribute is attached.

Attribute name for maximum elevation of contour polygon

Opcional

FIELD_NAME_MAX

[string]

Default: “ELEV_MAX”

Provides a name for the attribute in which to put the maximum elevation of contour polygon. If not provided no maximum elevation attribute is attached.

Produce 3D vector

CREATE_3D

[boolean]

Default: False

Forces production of 3D vectors instead of 2D. Includes elevation at every vertex.

Treat all raster values as valid

IGNORE_NODATA

[boolean]

Default: False

Ignores any nodata values in the dataset.

Input pixel value to treat as «nodata»

Opcional

NODATA

[number]

Default: None

Defines a value that should be inserted for the nodata values in the output raster

Additional command-line parameters

Opcional

EXTRA

[string]

Default: None

Add extra GDAL command line options. Refer to the corresponding GDAL utility documentation.

Contours

OUTPUT

[vector: polygon]

Default: “[Save to temporary file]”

Specification of the output vector layer. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here.

Resultados

Label

Nome

Type

Descrição

Contours

OUTPUT

[vector: polygon]

Output vector layer with contour polygons

Python code

Algorithm ID: gdal:contour_polygon

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 Usando os algoritmos do processamento a partir da consola for details on how to run processing algorithms from the Python console.