Raster extraction
=================

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.. _gdalcliprasterbyextent:

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

This algorithm is derived from the `GDAL grid utility <https://gdal.org/gdal_grid.html>`_ .

``Default menu``: :menuselection:`Raster --> Extraction`

Parameters
..........

.. list-table::
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   :widths: 20 20 20 40
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   * - 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>`).
   * - **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
   :stub-columns: 0

   * - Label
     - Name
     - Type
     - Description
   * - **Clipped (extent)**
     - ``OUTPUT``
     - [raster]
     - Output raster layer clipped by the given extent


.. _gdalcliprasterbymasklayer:

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

This algorithm is derived from the `GDAL grid utility <https://gdal.org/gdal_grid.html>`_ .

``Default menu``: :menuselection:`Raster --> Extraction`

Parameters
..........

.. list-table::
   :header-rows: 1
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   :stub-columns: 0

   * - Label
     - Name
     - Type
     - Description
   * - **Input layer**
     - ``INPUT``
     - [raster]
     - The input raster
   * - **Mask layer**
     - ``EXTENT``
     - [vector: polygon]
     - Vector mask for clipping the raster
   * - **Source CRS**
     - ``SOURCE_CRS``
     - [crs]
     -
   * - **Target CRS**
     - ``TARGET_CRS``
     - [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
   * - **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
     -
   * - **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>`).
   * - **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
   :stub-columns: 0

   * - Label
     - Name
     - Type
     - Description
   * - **Clipped (mask)**
     - ``OUTPUT``
     - [raster]
     - Output raster layer clipped by the vector layer


.. _gdalcontour:

Contour
-------
Extracts contour lines from any GDAL-supported elevation raster.

This algorithm is derived from the `GDAL contour utility <https://gdal.org/gdal_contour.html>`_ .

``Default menu``: :menuselection:`Raster --> Extraction`

Parameters
..........

.. list-table::
   :header-rows: 1
   :widths: 20 20 20 40
   :stub-columns: 0

   * - Label
     - Name
     - Type
     - Description
   * - **Input layer**
     - ``INPUT``
     - [raster]
     - Input raster
   * - **Band number**
     - ``BAND``
     - [raster band]
     - 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'
     - Defines the attribute name for the field containing the
       values of the contour lines.
   * - **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
   * - **Offset from zero relative to which to interpret intervals**

       Optional
     - ``OFFSET``
     - [number]

       Default: 0.0
     -
   * - **Additional command-line parameters**

       Optional
     - ``EXTRA``
     - [string]

       Default: None
     - Add extra GDAL command line options
   * - **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>`).
   * - **Contours**
     - ``OUTPUT``
     - [vector: line]

       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
   :stub-columns: 0

   * - Label
     - Name
     - Type
     - Description
   * - **Contours**
     - ``OUTPUT``
     - [vector: line]
     - Output vector layer with contour lines