Coordinate reset to int32 should only be performed if `netCDF3` output format is selected (or any format that doesn't support int64)

[atteggiani]

Overview

In the current implementation, within the process_cubes function, there is the following line that resets the coordinates to int32 in case they are int64:

um2nc-standalone/src/um2nc/um2netcdf.py

Lines 595 to 600 in b44e549

	# Check whether any of the coordinates is a pseudo-dimension with integer values and
	# if so, reset to int32 to prevent problems with possible later conversion to netCDF3
	for coord in c.coords():
	if coord.points.dtype == np.int64:
	coord.points = coord.points.astype(np.int32)

I think there are a few issues with this portion:

• The portion could be turn to a function to better explain its intent and be easily tested
• This portion might not be needed if the output netCDF supports int64 coordinates

Solution

• Turn the portion of code to a function (convert_coordinates_to_32_bit)
• Embed the whole code within an if condition that checks if the netcdf output format specified is not compatible with int64