Raster extraction
=================
.. only:: html
.. contents::
:local:
:depth: 1
.. _gdalcliprasterbyextent:
Clip raster by extent
---------------------
Clips any GDAL-supported raster file to a given extent.
This algorithm is derived from the
`GDAL warp utility <https://gdal.org/programs/gdalwarp.html>`_.
**Default menu**: :menuselection:`Raster --> Extraction`
Parameters
..........
.. list-table::
:header-rows: 1
:widths: 20 20 20 40
:class: longtable
* - Label
- Name
- Type
- Description
* - **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**
Optional
- ``NODATA``
- [number]
Default: None
- Defines a value that should be inserted for the nodata
values in 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
:ref:`GDAL driver options section <gdal_createoptions>`).
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**
Optional
- ``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
Outputs
.......
.. list-table::
:header-rows: 1
:widths: 20 20 20 40
* - Label
- Name
- Type
- Description
* - **Clipped (extent)**
- ``OUTPUT``
- [raster]
- Output raster layer clipped by the given extent
Python code
...........
**Algorithm ID**: ``gdal:cliprasterbyextent``
.. include:: ../qgis/qgis_algs_include.rst
:start-after: **algorithm_code_section**
:end-before: **end_algorithm_code_section**
.. _gdalcliprasterbymasklayer:
Clip raster by mask layer
-------------------------
Clips any GDAL-supported raster by a vector mask layer.
This algorithm is derived from the
`GDAL warp utility <https://gdal.org/programs/gdalwarp.html>`_.
**Default menu**: :menuselection:`Raster --> Extraction`
Parameters
..........
.. list-table::
:header-rows: 1
:widths: 30 20 20 30
:class: longtable
* - Label
- Name
- Type
- Description
* - **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**
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``
- [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**
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``
- [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**
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
:ref:`GDAL driver options section <gdal_createoptions>`).
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**
Optional
- ``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
Outputs
.......
.. list-table::
:header-rows: 1
:widths: 20 20 20 40
* - Label
- Name
- Type
- Description
* - **Clipped (mask)**
- ``OUTPUT``
- [raster]
- Output raster layer clipped by the vector layer
Python code
...........
**Algorithm ID**: ``gdal:cliprasterbymasklayer``
.. include:: ../qgis/qgis_algs_include.rst
:start-after: **algorithm_code_section**
:end-before: **end_algorithm_code_section**
.. _gdalcontour:
Contour
-------
Extracts contour lines from any GDAL-supported elevation raster.
This algorithm is derived from the
`GDAL contour utility <https://gdal.org/programs/gdal_contour.html>`_.
**Default menu**: :menuselection:`Raster --> Extraction`
Parameters
..........
.. list-table::
:header-rows: 1
:widths: 20 20 20 40
:class: longtable
* - Label
- Name
- Type
- Description
* - **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)**
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
-
* - **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"**
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.
* - **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.
Outputs
.......
.. list-table::
:header-rows: 1
:widths: 20 20 20 40
* - Label
- Name
- Type
- Description
* - **Contours**
- ``OUTPUT``
- [vector: line]
- Output vector layer with contour lines
Python code
...........
**Algorithm ID**: ``gdal:contour``
.. include:: ../qgis/qgis_algs_include.rst
:start-after: **algorithm_code_section**
:end-before: **end_algorithm_code_section**
.. _gdalcontour_polygon:
Contour Polygons
----------------
Extracts contour polygons from any GDAL-supported elevation raster.
This algorithm is derived from the
`GDAL contour utility <https://gdal.org/programs/gdal_contour.html>`_.
Parameters
..........
.. list-table::
:header-rows: 1
:widths: 20 20 20 40
:class: longtable
* - Label
- Name
- Type
- Description
* - **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**
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.
* - **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"**
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.
* - **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.
Outputs
.......
.. list-table::
:header-rows: 1
:widths: 20 20 20 40
* - Label
- Name
- Type
- Description
* - **Contours**
- ``OUTPUT``
- [vector: polygon]
- Output vector layer with contour polygons
Python code
...........
**Algorithm ID**: ``gdal:contour_polygon``
.. include:: ../qgis/qgis_algs_include.rst
:start-after: **algorithm_code_section**
:end-before: **end_algorithm_code_section**