24.2.5. Raster projections

24.2.5.1. Assign projection

Applies a coordinate system to a raster dataset.

This algorithm is derived from the GDAL edit utility.

Default menu: Raster ► Projections

參數

Label	名稱	Type	說明
Input layer	INPUT_LAYER	[raster]	Input raster layer
Desired CRS	CRS	[crs]	The projection (CRS) of the output layer

輸出

Label	名稱	Type	說明
Layer with projection	OUTPUT	[raster]	The output raster layer (with the new projection information)

Python code

Algorithm ID: gdal:assignprojection

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 Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.2.5.2. Extract projection

Extracts the projection of a raster file and writes it into a world file with extension .wld.

This algorithm is derived from the GDAL srsinfo utility.

Default menu: Raster ► Projections

參數

Label	名稱	Type	說明
Input file	INPUT_LAYER	[raster]	Input raster The raster layer has to be file based, as the algorithm uses the path to the raster file as the location of the generated .wld file. Using a non-file raster layer will lead to an error.
Create also .prj file	PRJ_FILE_CREATE	[boolean] Default: False	If this is activated a .prj file containing the projection information is also created.

輸出

Label	名稱	Type	說明
World file	WORLD_FILE	[file]	Text file with extension .wld containing transformation parameters for the raster file.
ESRI Shapefile prj file	PRJ_FILE	[file]	Text file with .prj extension that describes the CRS. Will be None if Create also .prj file is False.

Python code

Algorithm ID: gdal:extractprojection

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 Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

24.2.5.3. Warp (reproject)

Reprojects a raster layer into another Coordinate Reference System (CRS). The output file resolution and the resampling method can be chosen.

This algorithm is derived from the GDAL warp utility.

Default menu: Raster ► Projections

參數

Label	名稱	Type	說明
Input layer	INPUT	[raster]	Input raster layer to reproject
Source CRS Optional	SOURCE_CRS	[crs]	Defines the CRS of the input raster layer
Target CRS Optional	TARGET_CRS	[crs] Default: EPSG:4326	The CRS of the output layer
Resampling method to use	RESAMPLING	[enumeration] Default: 0	Pixel value resampling method to use. Options: 0 --- Nearest neighbour 1 --- Bilinear 2 --- Cubic 3 --- Cubic spline 4 --- Lanczos windowed sinc 5 --- Average 6 --- Mode 7 --- Maximum 8 --- Minimum 9 --- Median 10 --- First quartile 11 --- Third quartile
Nodata value for output bands Optional	NODATA	[number] Default: None	Sets nodata value for output bands. If not provided, then nodata values will be copied from the source dataset.
Output file resolution in target georeferenced units Optional	TARGET_RESOLUTION	[number] Default: None	Defines the output file resolution of reprojection result
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). 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. 選項： 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
Georeferenced extents of output file to be created Optional	TARGET_EXTENT	[extent]	Sets the georeferenced extent of the output file to be created (in the Target CRS by default. In the CRS of the target raster extent, if specified).
CRS of the target raster extent Optional	TARGET_EXTENT_CRS	[crs]	Specifies the CRS in which to interpret the coordinates given for the extent of the output file. This must not be confused with the target CRS of the output dataset. It is instead a convenience e.g. when knowing the output coordinates in a geodetic long/lat CRS, but wanting a result in a projected coordinate system.
Use multithreaded warping implementation	MULTITHREADING	[boolean] Default: False	Two threads will be used to process chunks of the image and perform input/output operations simultaneously. Note that the computation itself is not multithreaded.
Additional command-line parameters Optional	EXTRA	[string] Default: None	Add extra GDAL command line options.
Reprojected	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.

輸出

Label	名稱	Type	說明
Reprojected	OUTPUT	[raster] Default: [Save to temporary file]	Reprojected output raster layer

Python code

Algorithm ID: gdal:warpreproject

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 Using processing algorithms from the console for details on how to run processing algorithms from the Python console.