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[GEMPAK #COR-205453]: Plotting grid point values

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  • Subject: [GEMPAK #COR-205453]: Plotting grid point values
  • Date: Mon, 09 Mar 2009 18:53:37 -0600
Hi Bob,

Unfortunately the functionality you are asking about is not available, for a 
couple of different reasons. There exists functionality to color surface data 
points (the value of the scalar) based on value in SFMAP, but this is not 
available for grid data displayed at a point.

However, there is a workaround for grid data that is somewhat cumbersome but 
will produce products similar to those produced using the SFMAP method.  An 
example of this type of product can be seen here:

http://www.unidata.ucar.edu/software/gempak/tutorial/images/temps.jpg

Another workaround involves converting gridded data to a surface file using 
SFCFIL and GDGSFC and then plotting according to scalar value as you would with 
regular surface data.

The problem is that this functionality is limited to coloring a scalar value 
(such as tmpc) but not an arbitrary/user-defined symbol.

If you're interested in learning about either of these methods just let me know 
and I'll prepare a short write-up.

Best,

Michael James
Unidata User Support




is only available for surface data in SFMAP, not for grid data displayed at a 
point.



While not exactly easy, if someone were ambitious enough, they could look at 
the code in sfmap and apply it to the point display for gdplot2. SFMCLR 
interprets the user input and SFMPRM connects the colors and parameters. SFMPLT 
does the actual plotting with the color coding.

If you or someone else wants to work on this, I would be glad to review the 
code so that we can put it in the baseline.

Scott 

> Hi,
> 
> I'm using GEMPAK5.11.4 to plot data from a GEMPAK grid file.
> 1. We have a need to plot a symbol (such
> as a dot) at each grid point where the value of the variable is
> greater than zero or a given threshold.
> 2. Also, we would like to vary the color
> of the symbol to indicate the range of the data values.
> 
> I've tried using GDPLOT2 but could not find a way to do this.
> The only options seem to be plotting the numerical values
> at each grid point, or plotting a symbol at each grid point
> regardless of the data value.
> 
> Do you know of a way to accomplish the above type of plotting?
> 
> Thanks, -Bob Rabin
> 
> 


Ticket Details
===================
Ticket ID: COR-205453
Department: Support GEMPAK
Priority: High
Status: Open