I have image as ndarray with 20 bands with the following shape: (20, 2227, 3676) . I'm trying to save it using rasterio with the following script:


with rasterio.open(savedir /'myImage.tif', 
                                nodata=None, # change if data has nodata value
                                transform=img_transform) as dst:  
        for n in np.arange(0,20,1):

This fails with he following error:

---> 17 dst.write(img_arr[n,:,:],n+1)

File rasterio/_io.pyx:1700, in rasterio._io.DatasetWriterBase.write()

TypeError: object of type 'numpy.int64' has no len()

I'm not sure what is the source of this error, but I know that if I use the same script but instead of iterating through the bands I put manualy each band, it works. for example:


That works.

Hence, I don't know why I get the type error, and I don't waant to put manually all the bands of the image. How can I solve this issue?

  • Juste one question, why don't you do dst.write(img) ?
    – remi.braun
    Commented Feb 22, 2023 at 9:46
  • well usually if I don't specifiy the shape and the specific band, it get mismatched / fail
    – ReutKeller
    Commented Feb 22, 2023 at 10:04
  • You cannot have a mismatch between height/width/count if you specify them correctly : count=img.shape[0], height=img.shape[1], width=img.shape[2]
    – remi.braun
    Commented Feb 22, 2023 at 10:20
  • Ho, I just saw, but the driver should be "GTiff" -> rasterio.readthedocs.io/en/latest/…
    – remi.braun
    Commented Feb 22, 2023 at 10:34
  • thank you for this! that happened when I edited it from the original code, I have used GTiff originally :)
    – ReutKeller
    Commented Feb 22, 2023 at 12:23

2 Answers 2


It's not the dtype of the img array that's the problem, it's your n variable.

rasterio is expecting a python int not a numpy.int64 for the band number.

# this works
for n in range(0,1):
    dst.write(img[n,:, :], n+1)

# this works too
for n in np.arange(0,1):
    dst.write(img[n,:, :], int(n+1))

# this works for me

# this fails with `TypeError: object of type 'numpy.int64' has no len()`
for n in np.arange(0,1):
    dst.write(img[n,:, :], n+1) # n is np.int64 not int

What version of GDAL are you using ? It seems that tyou need a GDAL > 3.5.0 to have the support of writing INT64 dtype: https://github.com/OSGeo/gdal/issues/3325 (and rasterio > 1.3.0)

But do you really need INT64 ? It is really heavy on disk and usually useless.

  • I haven't downlaoded gdal to my venv. I'm using "rasterio==1.3.5.post1" , not sure where this post1 came from, to be honest. and for the data type - no , I don't neeed int64, the bands are either uint8 or float
    – ReutKeller
    Commented Feb 22, 2023 at 10:03
  • 1
    OK, rasterio 1.3.5 includes GDAL 3.5, no issue from that point of view. However, I strongly suggest you to convert your img to the dtype you really need, it will save you a lot of disk space
    – remi.braun
    Commented Feb 22, 2023 at 10:21

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