Hi Patrick,
Also, once you have opened your file in Ferret, you can just use the
command
SET AXIS/DEPTH sigma
to have Ferret treat it as a depth axis. Note how there is now a minus
sign in the #pts column on the SHOW AXIS listing.
yes? use multipleaxis.nc
yes? sh axis/all
name axis # pts start end
...
SIGMA Z 11 i 0.019148 0.98942
ALT Z (Km) 11 i 0.12948 37.295
yes? set axis/depth sigma
yes? sh axis/all
name axis # pts start end
sigma Z 11 i- 0.019148 0.98942
ALT Z (Km) 11 i 0.12948 37.295
and when you plot a variable whose Z axis is sigma, its upper axis
will have the axis in the correct direction.
Ansley
Ansley Manke wrote:
Hi Patrick
Yes, you can have vertical axes with different senses, positive upwards
or or downwards.
If you are creating the netcdf file, then adding this attribute to the
axis will ensure that it is treated as a depth axis.
sigma:positive = "down" ;
Or if defining an axis in Ferret, just add the qualifier /DEPTH to the
definition of the axis when it is to be positive in the downward
direction.
Ansley
Brockmann Patrick wrote:
Hi all,
How to store two vertical coordinates in different order in a netCDF
file ?
I have a 3D variable XYZ where Z is a sigma vertical coordinate
(from 1 at ground to 0 at the top of the atmosphere).
The netcdf variable is stored with k=1 ground, k=11 top of the atm
Now, if I define sigma as
sigma = 0.989417, 0.9596861, 0.9065547, 0.8214576, 0.7043947,
0.5639313,
0.4149028, 0.2744395, 0.1573766, 0.07227948, 0.01914804 ;
So with a decreasing order
when I open the file with ferret, the axis is reordered and variable is
then available with
an increase axis.
Thus I get
yes? shade var[k=1] representing top of the atmosphere. It should be
ground.
The problem could be a simple convention to accept but it is more
complicated to explain
if you have 2 vertical axis such as an altitude (with an increasing
order) and a sigma (with a descreasing order).
In first case k=1 will represent ground, k=11 in the second case.
k=1 should reprensent the ground in both case.
So is there a way to store in a netcdf file, one vertical axis in a
descreasing order and one in
an increasing order ?
Patrick
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