arcpy.NumpyToRaster fails with error two or three dimensional NumPy array is required

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10-31-2019 11:14 AM
CharlesFried
New Contributor III

The following code:

arcpy.AddMessage("shape of zOutput {} ".format(zOutput.shape))
arcpy.AddMessage("no of dimensions of zOutput {}".format(zOutput.ndim))
# Convert array to a geodatabase raster
myRaster = arcpy.NumPyArrayToRaster(zOutput, arcpy.Point(xmin,ymin), cellsize, cellsize, -999999)

produces the following output. As you can see the numpy array IS two dimensional. Yet NumPyArrayToRaster fails.

shape of zOutput (375, 524)
no of dimensions of zOutput 2
...
ValueError: Argument in_array: A two or three dimensional NumPy array is required.

Is this a bug in NumPyToRaster?  Is there some other way to export a numpy array to a raster?

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2 Replies
DanPatterson_Retired
MVP Esteemed Contributor

No it works fine

import arcpy

zOutput = np.random.randint(0, 10, size=(10,10)) # ---- some data

zOutput # ---- a raster
array([[6, 1, 6, 2, 4, 9, 7, 6, 5, 4],
[5, 2, 4, 3, 0, 0, 0, 4, 7, 2],
[5, 3, 6, 0, 5, 5, 7, 0, 4, 9],
[1, 4, 6, 4, 8, 2, 8, 5, 3, 6],
[2, 5, 0, 1, 8, 6, 8, 6, 6, 1],
[9, 0, 2, 0, 9, 1, 2, 5, 3, 7],
[2, 9, 5, 9, 0, 0, 6, 0, 0, 3],
[7, 9, 8, 1, 6, 7, 3, 6, 7, 6],
[0, 7, 4, 8, 5, 6, 4, 8, 1, 4],
[4, 6, 7, 0, 9, 9, 3, 3, 6, 0]])

type(zOutput) # ---- the type, shape, whatever you need
numpy.ndarray

# ---- out it goes... then save it, preferably as a *.tif!!!
myRaster = arcpy.NumPyArrayToRaster(zOutput, arcpy.Point(0.0,0.0), 1.0, 1.0, -999999)
myRaster.save("c:/temp/a.tif")

# ---- close the loop as a test
back_in = arcpy.RasterToNumPyArray("c:/temp/a.tif")
type(back_in)
numpy.ndarray

back_in
array([[6, 1, 6, 2, 4, 9, 7, 6, 5, 4],
[5, 2, 4, 3, 0, 0, 0, 4, 7, 2],
[5, 3, 6, 0, 5, 5, 7, 0, 4, 9],
[1, 4, 6, 4, 8, 2, 8, 5, 3, 6],
[2, 5, 0, 1, 8, 6, 8, 6, 6, 1],
[9, 0, 2, 0, 9, 1, 2, 5, 3, 7],
[2, 9, 5, 9, 0, 0, 6, 0, 0, 3],
[7, 9, 8, 1, 6, 7, 3, 6, 7, 6],
[0, 7, 4, 8, 5, 6, 4, 8, 1, 4],
[4, 6, 7, 0, 9, 9, 3, 3, 6, 0]])
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CharlesFried
New Contributor III

It turns out that if the numpy array is masked, the NumpyToRaster fails with the misleading error message about the dimensions of the array.  So the solution is to fill the masked array before running the command.