27.2.5. Raster projections

27.2.5.1. Assign projection

Applies a coordinate system to a raster dataset.

This algorithm is derived from the GDAL edit utility.

Default menu: Raster ► Projections

参数

标注	名称	类型	描述
输入图层	INPUT_LAYER	[栅格]	Input raster layer
Desired CRS	CRS	[crs]	The projection (CRS) of the output layer

输出

标注	名称	类型	描述
Layer with projection	OUTPUT	[栅格]	The output raster layer (with the new projection information)

Python代码

Algorithm ID: gdal:assignprojection

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

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.2.5.2. 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

参数

标注	名称	类型	描述
Input file	INPUT_LAYER	[栅格]	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.

输出

标注	名称	类型	描述
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代码

Algorithm ID: gdal:extractprojection

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

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.2.5.3. 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

参数

Basic parameters

标注	名称	类型	描述
输入图层	INPUT	[栅格]	Input raster layer to reproject
Source CRS 可选	SOURCE_CRS	[crs]	Defines the CRS of the input raster layer
Target CRS 可选	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 可选	NODATA	[数字] 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 可选	TARGET_RESOLUTION	[数字] Default: None	Defines the output file resolution of reprojection result
Reprojected	OUTPUT	[栅格] 默认: [保存到临时文件]	Specification of the output raster layer. One of: 保存到临时文件 保存到文件…

Advanced parameters

标注	名称	类型	描述
Additional creation options 可选	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) Available options depend on the GDAL version built with QGIS (see Help ► About menu)
Georeferenced extents of output file to be created 可选	TARGET_EXTENT	[范围]	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). 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
CRS of the target raster extent 可选	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 可选	EXTRA	[string] Default: None	Add extra GDAL command line options.

输出

标注	名称	类型	描述
Reprojected	OUTPUT	[栅格] 默认: [保存到临时文件]	Reprojected output raster layer

Python代码

Algorithm ID: gdal:warpreproject

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

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。