Re: [ferret_users] Finding the coordinate value along an axis.

["Ansley C. Manke" <ansley.b.manke@xxxxxxxx>]

    Hi Alexander
    
    Are you working from the PyFerret command line,that is from the
    "yes?"  prompt?  If so you can define a variable that contains the
    coordinates of an axis.  The topic in the documentation is
    "pseudo-variables".  
    
    let zval = z[gz=variable]
    repeat/k=1:32 (let val= `zval`)
    
    
    There is syntax for controling the formatting of values in the
    grave-accent expressions, which may be useful to you when using
    numeric values within a file name.  See this:
https://ferret.pmel.noaa.gov/Ferret/documentation/users-guide/variables-xpressions/EMBEDDED-XPRESSIONS#_VPINDEXENTRY_562

On 9/2/2020 1:02 PM, Alexander Audet wrote:

Hello Everyone,

                           I am trying to return coordinate values along an irregular axis using the index values. So if I have 32 pressure levels (K=1:32:1) spread out between Z=100-1000mb, I might want to say get the value 500 (mb ~ but without the mb) from inputting K=17 somehow. 

What I have done:

I came across the pyferret.get_axis_coordinates ETF, however, that seems to require I code my own ETF to use. Either way, I am still confused about how to use it, and how it could help me get the result I want, even after using help(pyferret.get_axis_coordinates).

It has crossed my mind that I may be able to somehow create a new axis from the old ending at K=17, and then return the end value by using RETURN=XEND. However, I do not currently know how to create a subaxis from another axis. 

What I am actually trying to do (in case that helps): 

I am running a REPEAT and want to create a series of file names with the appropriate pressure levels in the file name. I have a variety of different files, so no 1 size fits all. 

Many thanks,

Alexander

-- 
Ansley Manke
Science Data Integration Group
NOAA Pacific Marine Environmental Laboratory
7600 Sand Point Way NE
Seattle WA 98115

I am currently teleworking and am available Tue-Wed-Thu.