ACE/gr (aka xmgr) does netCDF

• To: netcdfgroup@xxxxxxxxxxxxxxxx
• Subject: ACE/gr (aka xmgr) does netCDF
• From: pturner@xxxxxxxxxxxxxxxxxxx (Paul J Turner)
• Date: Mon, 18 Apr 1994 09:52:57 -0700

ACE/gr (aka xmgr) is an XY plotting tool written to X11/Motif. 
You'll need an ANSI compiler and at least X11R4+Motif 1.1 to 
build it.

I'm nearing the end of the alpha test for ACE/gr v 3.00 and 
I've included support for reading 1 dimensional variables 
from netCDF files (only two data types, NC_FLOAT and NC_DOUBLE,
for now).  If you are interested in such a thing, the alpha test is
available via anonymous ftp to:

ftp.ccalmr.ogi.edu:/CCALMR/pub/acegr/xmgr-3.00alpha.tar.Z

This particular alpha has been compiled on RS6000s only
but should build on SGIs, HPs, and Suns (with Motif) without
too much difficulty.

Usage as follows:

New command line options

-netcdf [netCDF file]
-netcdfxy [xvar or "null"] [yvar]

Where xvar and yvar are the names of the variables to read.

if xvar == "null", then load the index of yvar.

These command line options may be used to read variables from
a netCDF file. For example:

xmgr -netcdf t.nc -netcdfxy null y

Reads y from t.nc and loads to X the index (starting from 1).

xmgr -netcdf t.nc -netcdfxy x y -netcdfxy x1 y1

Reads x and y from t.nc, then x1 and y1 from the same file.
2 sets are created, both of type XY, one with (x, y), the
other composed of (x1, y1).

another example reading data from 2 CDF files:

xmgr -netcdf t.nc -netcdfxy x y -netcdf t2.nc -netcdfxy x1 y1


There is a new popup that works as follows:

---------------------------------------
   File/Read netCDF

---------------------------------------
   Select X:    Select Y:

   netCDF file:
   Load to set:
   Autoscale on read

   Accept   Files...   Update   Query   Done
---------------------------------------

Enter the name of the netCDF file in the text item labelled
"netCDF file:" then click on "Update" (note that if -netcdf
[filename] was used on the command line, this step is not
needed, as the lists will be loaded automatically). This will 
read the names of all one dimensional variables into the 
two scrolled lists.  The leftmost list is for X and the 
rightmost for Y. There is an additional item in the X 
list called INDEX (I'm hoping here that no one names a 
variable INDEX, maybe I need to change this) that indicates 
that for X, use the index of the Y variable (numbering 
starts from 1).

Select on a variable from the X list to use for X and select
a variable from the Y list (only single selections for now). 

If information about the selected variables is desired, click on 
Query. Presently, only the values of character attributes are 
displayed.

Select a set using "Load to set:" - the default is to load
to the next available set.

If things look OK, click on Accept to read the data and load 
the set. Use "Autoscale on read" to set/unset autoscaling
after a successful read.

To read data from a new CDF file, enter the filename, or use
File... to scan the directory. Click on Update to freshen up
the X and Y selection lists.

Presently only sets of type XY are created.

If you decide to try it, let me know about problems you 
encounter, enhancements, etc.

--Paul

Paul J Turner
pturner@xxxxxxxxxxxxxxxxxxx