我需要从4波段图像中提取3个波段。我使用一个名为NumpyArrayToRaster()的函数,它最多只接受3个波段图像。如何使它适用于4波段图像?在
这是我现在的密码-
import arcpy
arcpy.CheckOutExtension("Spatial")
from PIL import Image
import matplotlib.pyplot as plt
import numpy as np
from skimage import io
from skimage.segmentation import quickshift
arcpy.env.overwriteOutput = True
# The input 4-band NAIP image
img = r'C:\Users\Alekhya\Desktop\Krishna\NRSC\processed image\newclip4\clip4.tif'
# Convert image to numpy array
imgarr = io.imread(img)
print imgarr
print imgarr.shape
print imgarr.dtype
# Run the quick shift segmentation
segments = quickshift(imgarr, kernel_size=3, convert2lab=False, max_dist=6, ratio=0.5)
print("Quickshift number of segments: %d" % len(np.unique(segments)))
# View the segments via Python
plt.imshow(segments)
print segments
print segments.shape
print type(segments)
print segments.dtype
# Get raster metrics for coordinate info
imgRaster = arcpy.sa.Raster(img)
# Lower left coordinate of block (in map units)
mx = imgRaster.extent.XMin
my = imgRaster.extent.YMin
sr = imgRaster.spatialReference
'''
# Note the use of arcpy to convert numpy array to raster
seg = arcpy.NumPyArrayToRaster(segments, arcpy.Point(mx,my), imgRaster.meanCellWidth, imgRaster.meanCellHeight)
outRaster = r'C:\Users\Alekhya\Desktop\Krishna\NRSC\processed image\newclip4\segments_clip4.tif'
seg_temp = seg.save(outRaster)
arcpy.DefineProjection_management(outRaster, sr)
'''
# Calculate NDVI from bands 4 and 3
b4 = arcpy.sa.Raster(r'C:\Users\Alekhya\Desktop\Krishna\NRSC\processed image\newclip4\clip4.tif\Band_4')
b3 = arcpy.sa.Raster(r'C:\Users\Alekhya\Desktop\Krishna\NRSC\processed image\newclip4\clip4.tif\Band_3')
ndvi = arcpy.sa.Float(b4-b3) / arcpy.sa.Float(b4+b3)
print ndvi
# Extract NDVI values based on image object boundaries
zones = arcpy.sa.ZonalStatistics(segments, "VALUE", ndvi, "MEAN")
zones.save(r'C:\Users\Alekhya\Desktop\Krishna\NRSC\processed image\newclip4\zones_clip4.tif')
# Classify the segments based on NDVI values
binary = arcpy.sa.Con(zones < 20, 1, 0)
binary.save(r'C:\Users\Alekhya\Desktop\Krishna\NRSC\processed image\newclip4\classified_clip4.tif')
在阅读代码时,我意识到您需要计算NDVI值。也许您可以稍微修改一下您的方法,而不是使用函数
NumpyArrayToRaster(
),您可以使用更简单的方法?在这里我提供我的代码,它: -从多个日期读取单个的哨兵数据堆栈(多波段合成) -使用
rasterName/Band_X
确定NDVI计算所需的波段 -从波段计算NDVI -将每个日期的NDVIs保存到输出文件夹,保留其名称和日期在陆地卫星中,NDVI的波段是波段4和波段3
我的代码:
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