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28.2.3. Raster extraction

28.2.3.1. Clip raster by extent

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

This algorithm is derived from the GDAL translate utility.

Default menu: Raster ► Extraction

Параметры

Basic parameters

Ярлык

Имя

Тип

Описание

Исходный слой

INPUT

[растр]

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.

Available methods are:

  • Calculate from layer…: uses extent of a layer loaded in the current project

  • Calculate from layout map…: uses extent of a layout map item in the active project

  • Calculate from bookmark…: uses extent of a saved bookmark

  • Use map canvas extent

  • Draw on canvas: click and drag a rectangle delimiting the area to take into account

  • Enter the coordinates as xmin, xmax, ymin, ymax

Override the projection for the output file

OVERCRS

[логическое значение]

По умолчанию: Ложь

If checked, the output file is assigned the input layer CRS.

Assign a specified NoData value to output bands

Optional

NODATA

[number]

Default: None

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

Clipped (extent)

OUTPUT

[растр]

По умолчанию: [Сохранить во временный файл]

Specification of the output raster layer. One of:

  • Сохранить во временный файл

  • Save to File…

Advanced parameters

Ярлык

Имя

Тип

Описание

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).

Batch Process and Model Designer: 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 (Eight bit unsigned integer (quint8))

  • 2 — Int16 (Sixteen bit signed integer (qint16))

  • 3 — UInt16 (Sixteen bit unsigned integer (quint16))

  • 4 — UInt32 (Thirty two bit unsigned integer (quint32))

  • 5 — Int32 (Thirty two bit signed integer (qint32))

  • 6 — Float32 (Thirty two bit floating point (float))

  • 7 — Float64 (Sixty four bit floating point (double))

  • 8 — CInt16 (Complex Int16)

  • 9 — CInt32 (Complex Int32)

  • 10 — CFloat32 (Complex Float32)

  • 11 — CFloat64 (Complex Float64)

  • 12 — Int8 (Eight bit signed integer (qint8))

Available options depend on the GDAL version built with QGIS (see Help ► About menu)

Additional command-line parameters

Optional

EXTRA

[string]

Default: None

Add extra GDAL command line options

Результаты

Ярлык

Имя

Тип

Описание

Clipped (extent)

OUTPUT

[растр]

Output raster layer clipped by the given extent

Код на Python

Algorithm ID: gdal:cliprasterbyextent

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

ID алгоритма отображается при наведении мыши на алгоритм в Инструментах анализа. Словарь parameter dictionary содержит ключи параметров и их значения. См. Изпользование алгоритмов геообработки в консоли для детального описания того, как запускать алгоритмы анализа из консоли Python.

28.2.3.2. 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

Параметры

Basic parameters

Ярлык

Имя

Тип

Описание

Исходный слой

INPUT

[растр]

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

Target extent

Optional

TARGET_EXTENT

[extent]

Extent of the output file to be created

Available methods are:

  • Calculate from layer…: uses extent of a layer loaded in the current project

  • Calculate from layout map…: uses extent of a layout map item in the active project

  • Calculate from bookmark…: uses extent of a saved bookmark

  • Use map canvas extent

  • Draw on canvas: click and drag a rectangle delimiting the area to take into account

  • Enter the coordinates as xmin, xmax, ymin, ymax

Assign a specified NoData value to output bands

Optional

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

[логическое значение]

По умолчанию: Ложь

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

[логическое значение]

Default: True

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

Keep resolution of input raster

KEEP_RESOLUTION

[логическое значение]

По умолчанию: Ложь

The resolution of the output raster will not be changed

Set output file resolution

SET_RESOLUTION

[логическое значение]

По умолчанию: Ложь

Shall the output resolution (cell size) be specified

X Resolution to output bands

Optional

X_RESOLUTION

[number]

Default: None

The width of the cells in the output raster

Y Resolution to output band

Optional

Y_RESOLUTION

[number]

Default: None

The height of the cells in the output raster

Use multithreaded warping implementation

MULTITHREADING

[логическое значение]

По умолчанию: Ложь

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

Clipped (mask)

OUTPUT

[растр]

По умолчанию: [Сохранить во временный файл]

Specification of the output raster layer. One of:

  • Сохранить во временный файл

  • Save to File…

Advanced parameters

Ярлык

Имя

Тип

Описание

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).

Batch Process and Model Designer: 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 (Eight bit unsigned integer (quint8))

  • 2 — Int16 (Sixteen bit signed integer (qint16))

  • 3 — UInt16 (Sixteen bit unsigned integer (quint16))

  • 4 — UInt32 (Thirty two bit unsigned integer (quint32))

  • 5 — Int32 (Thirty two bit signed integer (qint32))

  • 6 — Float32 (Thirty two bit floating point (float))

  • 7 — Float64 (Sixty four bit floating point (double))

  • 8 — CInt16 (Complex Int16)

  • 9 — CInt32 (Complex Int32)

  • 10 — CFloat32 (Complex Float32)

  • 11 — CFloat64 (Complex Float64)

  • 12 — Int8 (Eight bit signed integer (qint8))

Available options depend on the GDAL version built with QGIS (see Help ► About menu)

Additional command-line parameters

Optional

EXTRA

[string]

Default: None

Add extra GDAL command line options

Результаты

Ярлык

Имя

Тип

Описание

Clipped (mask)

OUTPUT

[растр]

Output raster layer clipped by the vector layer

Код на Python

Algorithm ID: gdal:cliprasterbymasklayer

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

ID алгоритма отображается при наведении мыши на алгоритм в Инструментах анализа. Словарь parameter dictionary содержит ключи параметров и их значения. См. Изпользование алгоритмов геообработки в консоли для детального описания того, как запускать алгоритмы анализа из консоли Python.

28.2.3.3. Contour

Extracts contour lines from any GDAL-supported elevation raster.

This algorithm is derived from the GDAL contour utility.

Default menu: Raster ► Extraction

Параметры

Basic parameters

Ярлык

Имя

Тип

Описание

Исходный слой

INPUT

[растр]

Input raster

Номер канала

BAND

[канал растра]

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)

Optional

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

Optional

OFFSET

[number]

Default: 0.0

Contours

OUTPUT

[vector: line]

По умолчанию: [Сохранить во временный файл]

Specification of the output vector layer. One of:

  • Сохранить во временный файл

  • Save to File…

Advanced parameters

Ярлык

Имя

Тип

Описание

Produce 3D vector

CREATE_3D

[логическое значение]

По умолчанию: Ложь

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

Treat all raster values as valid

IGNORE_NODATA

[логическое значение]

По умолчанию: Ложь

Ignores any NoData values in the dataset.

Input pixel value to treat as «NoData»

Optional

NODATA

[number]

Default: None

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

Additional command-line parameters

Optional

EXTRA

[string]

Default: None

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

Результаты

Ярлык

Имя

Тип

Описание

Contours

OUTPUT

[vector: line]

Output vector layer with contour lines

Код на Python

Algorithm ID: gdal:contour

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

ID алгоритма отображается при наведении мыши на алгоритм в Инструментах анализа. Словарь parameter dictionary содержит ключи параметров и их значения. См. Изпользование алгоритмов геообработки в консоли для детального описания того, как запускать алгоритмы анализа из консоли Python.

28.2.3.4. Contour Polygons

Extracts contour polygons from any GDAL-supported elevation raster.

This algorithm is derived from the GDAL contour utility.

Параметры

Basic parameters

Ярлык

Имя

Тип

Описание

Исходный слой

INPUT

[растр]

Input raster

Номер канала

BAND

[канал растра]

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

Optional

OFFSET

[number]

Default: 0.0

Attribute name for minimum elevation of contour polygon

Optional

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

Optional

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.

Contours

OUTPUT

[vector: polygon]

По умолчанию: [Сохранить во временный файл]

Specification of the output vector layer. One of:

  • Сохранить во временный файл

  • Save to File…

Advanced parameters

Ярлык

Имя

Тип

Описание

Produce 3D vector

CREATE_3D

[логическое значение]

По умолчанию: Ложь

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

Treat all raster values as valid

IGNORE_NODATA

[логическое значение]

По умолчанию: Ложь

Ignores any NoData values in the dataset.

Input pixel value to treat as «NoData»

Optional

NODATA

[number]

Default: None

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

Additional command-line parameters

Optional

EXTRA

[string]

Default: None

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

Результаты

Ярлык

Имя

Тип

Описание

Contours

OUTPUT

[vector: polygon]

Output vector layer with contour polygons

Код на Python

Algorithm ID: gdal:contour_polygon

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

ID алгоритма отображается при наведении мыши на алгоритм в Инструментах анализа. Словарь parameter dictionary содержит ключи параметров и их значения. См. Изпользование алгоритмов геообработки в консоли для детального описания того, как запускать алгоритмы анализа из консоли Python.