Python GDAL writing image output all pixels as zeros

Question

I have an array "array" with numbers range from -5 to 1 (with decimal) and I tried to write it as a geotiff. However, the output geotiff turns out to be all zeros. Can someone tell me why? Here the code.

from osgeo import gdal
ds = gdal.Open('test.tif', gdal.GA_ReadOnly)
driver = gdal.GetDriverByName("GTiff")
outdata = driver.Create('output.tif', array.RasterXSize, array.RasterYSize, 1, gdal.GDT_Float32)
outdata.SetGeoTransform(ds.GetGeoTransform())
outdata.SetProjection(ds.GetProjection())
outband = outdata.GetRasterBand(1)
outband.WriteArray(array)
outband.FlushCache() 

• Marcelo Villa: Maybe add del outdata to the end of the script althought you are already calling FlushCache().
• J.Wang: Thanks, Marcelo. You were right. But I don't understand why deleting outdata is necessary?

Answer 1

You have to delete the output dataset to make sure the script releases that object from memory (although it should do it at the end of the exectution). You can do this by adding del outdata at the end of your script. I always use both band.FlushCache() (which writes the data to disk) and del outdata to make sure I don't end up with an empty array.

• J.Wang: Thanks! That was helpful.
• Marcelo Villa: Glad it was helpful! If it solved your issue marked the answer as accepted so the question is closed.