20011015: ploting realtime grids

>From: Owen Cooper <address@hidden>
>Organization: NOAA Aeronomy Laboratory, R/AL4
>Keywords: 200110152028.f9FKS0123855 McIDAS GRDDISP

Owen,

>Okay, how do I get around this one?
>
>I have a batch that plots AVN realtime grids every six hours, fired off by
>a cron job.
>The AVN data have several projections:
>a full northern hemisphere polar stereographic
>2 polar stereographic versions of N. AMerica
>1 Mercator of the the entire planet
>
>If I use the command:
>GRDDISP RTGRIDS/AVN DAY=#Y TIME=0 PARAM=P LEV=MSL FHOUR=0
>
>It will grab the first GRID that fits this decription and plot it up.

Right.

>This is usually the northern hemi. polar-stereographic, the one that I
>want.

This is not, however, guaranteed.

>But often the first grid that fits this description is one of the
>North American plots, which does me no good as I want to see what's going
>on over Europe.  Is there any way to tell MCIDAS which specific projection
>I want?

Yes.  Use the GPRO= keyword for GRDDISP.  For instance, the following
will always get you the LAMBert Conformal grid:

GRDDISP RTGRIDS/AVN DAY=#Y TIME=0 PARAM=P LEV=MSL FHOUR=0 GPRO=LAMB

>It doesn't look like specifying the grid number will do any good
>seeing as the grid numbers change in addition to the order in which the
>projections are available.

Right.  In order to use the grid number, you would have to do a
GRDLIST to find out the grid numbers first (ugly).  Using the GPRO=
keyword will get you around this, but it wouldn't get you around the
case where you have more than one Lambert Conformal grid of P at MSL
for the same DAY and TIME you are interested in.  For that case, you
would have to do a list and then use the grid number.

>Any suggestions?

Let me know if you run into amy problems using GPRO=.

>Thanks
>Owen
>
>Owen Cooper
>National Research Council Associate
>NOAA Aeronomy Laboratory, R/AL4
>325 Broadway
>Boulder CO 80305
>ph: (303) 497-3599
>fax: (303) 497-5686

Tom