GDAL WriteArray问题 [英] GDAL WriteArray issue

问题描述

我正在使用python GDAL将栅格数据写入.tif文件.这是代码:

I'm utilizing python GDAL to write a raster data into a .tif file. Here's the code:

import numpy, sys
from osgeo import gdal, utils
from osgeo.gdalconst import *

# register all of the GDAL drivers
gdal.AllRegister()

# open the image
inDs = gdal.Open("C:\\Documents and Settings\\patrick\\Desktop\\tiff elevation\\EBK1KM\\color_a1.tif",GDT_UInt16)
if inDs is None:
  print "couldn't open input dataset"
  sys.exit(1)
else:
  print "opening was successful!"
cols = inDs.RasterXSize
rows = inDs.RasterYSize
bands =  inDs.RasterCount
driver = inDs.GetDriver()
driver.Create("C:\\Documents and Settings\\patrick\\Desktop\\tiff elevation\\EBK1KM\\newfile.tif",cols,rows,3,GDT_UInt16)
outDs = gdal.Open("C:\\Documents and Settings\\patrick\\Desktop\\tiff elevation\\EBK1KM\\newfile.tif")

if outDs is None:
  print "failure to create new file"
  sys.exit(1)


outBand1 = outDs.GetRasterBand(1)
outBand2 = outDs.GetRasterBand(2)
outBand3 = outDs.GetRasterBand(3)
data1 = inDs.GetRasterBand(1).ReadAsArray()
data2 = inDs.GetRasterBand(2).ReadAsArray()
data3 = inDs.GetRasterBand(3).ReadAsArray()

outBand1.WriteArray(data1,0,0)
outBand2.WriteArray(data2,0,0)
outBand3.WriteArray(data3,0,0)

print "before closing out the file"
print outDs.GetRasterBand(1).ReadAsArray(700,700,5,5)
print outDs.GetRasterBand(2).ReadAsArray(700,700,5,5)
print outDs.GetRasterBand(3).ReadAsArray(700,700,5,5)

outDs.SetProjection(inDs.GetProjection())
outDs.SetGeoTransform(inDs.GetGeoTransform())

outDs = None
outDs = gdal.Open("C:\\Documents and Settings\\patrick\\Desktop\\tiff elevation\\EBK1KM\\newfile.tif")
print "after reopening"
print outDs.GetRasterBand(1).ReadAsArray(700,700,5,5)
print outDs.GetRasterBand(2).ReadAsArray(700,700,5,5)
print outDs.GetRasterBand(3).ReadAsArray(700,700,5,5)

在关闭和重新打开输出数据集之间的结果输出是不同的:

The resultant output between the closing and reopening of the output dataset are different:

before closing out the file
[[ 36  35  55 121   0]
 [ 54   0 111 117   0]
 [  0 117 152  56   0]
 [ 89 122  56   0   0]
 [102 107   0  25  53]]
[[ 68  66 126 200   0]
 [ 78   0 166 157   0]
 [  0 235 203  70   0]
 [229 251 107   0   0]
 [241 203   0  42 121]]
[[0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]]
after reopening
[[0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]]
[[0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]]
[[0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]
 [0 0 0 0 0]]

在将变量设置为None之前，是否缺少某些命令来确保文件已写入并保存?我尝试添加以下两项都没有运气:

is there some command I'm missing to ensure that the file is written and saved prior to setting the variable to None? I've tried adding both of the following with no luck:

outband1.FlushCache()
outDs.FlushCache()

推荐答案

您不需要先Create然后Open一个栅格(您正在阅读GA_ReadOnly).您也不需要一开始的gdal.AllRegister()，因为在将GDAL加载到Python中时已经调用了它(请参见

You don't need to Create then Open a raster (which you were reading GA_ReadOnly). You also don't need gdal.AllRegister() at the beginning, as it has already been called when you load GDAL into Python (see the Raster API tutorial).

在上方某处拾起(有修改):

Picking up somewhere above (with modifications):

# Create a new raster data source
outDs = driver.Create(out_fname, cols, rows, 3, gdal.GDT_UInt16)

# Write metadata
outDs.SetGeoTransform(inDs.GetGeoTransform())
outDs.SetProjection(inDs.GetProjection())

# Write raster data sets
for i in range(3):
    outBand = outDs.GetRasterBand(i + 1)
    outBand.WriteArray(data[i])

# Close raster file
outDs = None

有时，我添加此代码是为了确保文件已完全释放，并防止遇到某些 gotchas :

Sometimes I add this to ensure the file is fully deallocated, and to prevent running into some gotchas:

del outDs, outBand

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