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 `_. **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 `). 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 `_. **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 `). 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 `_. **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 `_. 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**