Re: [ferret_users] Trouble creating an ensemble in Pyferret.

[Ansley Manke <a.c.manke@xxxxxxxxx>]

On 10/18/2023 6:47 PM, Ryo Furue wrote:

Dear Edward,

I’m trying to read 2 data sets and make them into an ensemble.  Each data set has several, but not all, variables in common.  When I read them into Pyferret v. 7.6.5, Pyferret cannot find any variable names with the same grids in common, but that is not true.  Most of my variables on the same grid are in each data set.  Below is the Pyferret session.  Any suggestions?

The first thing you want to look at is the outputs from the `ncdump -h` command.  On your command line,

ncdump -h hydrography_bttm_2008.nc

ncdump -h hydrography_bttm_2019.nc

and compare the outputs to see if the variables you want to use really have the same axes.

Ryo

... or , in the PyFerret session,

yes? show grid variable_name

for variables of the same name in the two datasets.  As datasets are opened, the axes are compared with any axis definitions that have already been made.  The axis name, units, coordinates, positive direction (for z axes), and time origin (for time axes) must be identical.  The messages you're seeing Ned, when trying to define the ensemble, indicate there's some difference.  Then of course, commands like

yes? show axis/x xaxis_name

will list this info for the axes, including the coordinate values, and you'll be able to see how they differ.