GeometricMedian

获得 Image Analyst 许可后可用。

摘要

计算多波段影像时间序列中像素的几何中值。

说明

有关此函数工作原理的详细信息，请参阅几何中值函数。

栅格对象所引用的栅格数据集是临时性的。 要将其设置为永久，可以调用栅格对象的 save 方法。

语法

GeometricMedian (rasters, epsilon, {max_iteration}, {extent_type}, {cellsize_type})

参数	说明	数据类型
rasters [rasters,...]	The input multiband rasters.	List
epsilon	The convergence value between two consecutive iterations. When epsilon is less than or equal to the specified value, the iteration will stop, and the result of the last iteration will be used. (默认值为 0.001)	Double
max_iteration	The maximum number of iterations to complete. The computation will end once this value is reached, regardless of the epsilon setting. (默认值为 10)	Integer
extent_type	Specifies the processing extent for the output raster. FirstOf—Use the extent of the first input raster to determine the processing extent. IntersectionOf—Use the extent of the overlapping pixels to determine the processing extent. This is the default. UnionOf—Use the extent of all the rasters to determine the processing extent. LastOf—Use the extent of the last input raster to determine the processing extent. (默认值为 IntersectionOf)	String
cellsize_type	Specifies the cell size to use in the output raster. FirstOf—Use the first cell size of the input rasters. This is the default. MinOf—Use the smallest cell size of all the input rasters. MaxOf—Use the largest cell size of all the input rasters. This is the default. MeanOf—Use the mean cell size of all the input rasters. LastOf—Use the last cell size of the input rasters. (默认值为 MaxOf)	String

返回值

数据类型	说明
Raster	输出栅格对象。

代码示例

GeometricMedian 示例

此示例计算 Landsat 影像集合中的几何中值。

# Import system modules
import arcpy
from arcpy.ia import *

# Check out the ArcGIS Image Analyst extension license
arcpy.CheckOutExtension("ImageAnalyst")

# Construct a collection from a mosaic dataset
rc = RasterCollection(r'C:\data.gdb\time_series_landsat_images')

#Execute
geomedian = arcpy.ia.GeometricMedian(rc, {"epsilon": 0.001, "max_iteration": 5, "extent_type":"UnionOf", "CellsizeType": "FirstOf"})

# Save the output
geomedian.save("C:/arcpyExamples/outputs/geomedian_raster.crf")