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20020706: GDRADR problems, projection and grid size errors

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  • Subject: 20020706: GDRADR problems, projection and grid size errors
  • Date: Mon, 08 Jul 2002 06:59:55 -0600
>From: "CORENE J MATYAS" <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200207061438.g66Ecnn17110

>Hi. I?m having difficulty with GDRADR and am receiving errors regarding the pro
> jection and grid size. I?m using archived NIDS radar data and would like to cr
> eate composites of 4 or 5 neighboring stations.   I need to create high-res G
> IF images so I can use standard geographical/image analysis tools. The data?s 
> path is ?pub/NIDS/SITE/PROD/YYYYMMDDHHNN?, with ?YYYYMMDDHHNN? being the name 
> of 
> the NIDS image (this path can be changed if absolutely necessary, but I?d like
>  to avoid it if possible). I modified the NEXRIII entry in the datatype.tbl t
> o reflect this path and filename structure and created a station table that o
> nly includes the 3 stations I am using for my test run. I?ve entered several d
> ifferent ?grdarea? variables including FL state, MLB station, and coordinates 
> f
> or an area around Florida. I set ?proj = RAD? and I?ve left ?cpyfil? blank. I 
> don?t
>  quite understand what values should be entered for ?KXKY? - I tried to 
> create 
> a national composite using ?720;500? as in the !
>gdradr example 1 with the original station table file. But, I don?t understand 
> how grid points map to image pixels, or lat/lon coordinates. I?ve tried a rang
> e but for both those attempts as well as the national attempt, I received err
> ors of ?invalid projection? and ?invalid grid size?. I?ve attempted to view 
> all of
>  the output files in ?gdplot2?, but they appear blank ? no radar data 
> (although 
> state and lat/lon lines appear), so I?m assuming that ?gdradr? didn?t 
> successfull
> y run.   
>Can you offer any help? Thanks a lot.
>
>

Set PROJ to the projection you want for your grid, not RAD.

For example, PROJ=ced, or PROJ=str/90;-105;0 
The set GAREA to the area that the grid will cover.

KXKY is the number of X and Y grid points in the resulting grid. The number of
grid points should be <= 400,000 (the default maximum grid size in gempak).

Steve Chiswell
Unidata User Support