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Re: 20000810: gdcross axis




James,
 
You are using the ETA 211 grid as given below, with cross section longitudes
from -100 to -60. The problem is as I mentioned previously. The eastern extent
of the ETA grid does not reach 60W for points south of 32N or so.
 
The gdinfo you provide shows the lower left and upper right of the grid, which
is on a LCC projection. The lower right corner of the grid is at
approximately 17N 65W. 

As I mentioned previously, if you display the data points from the ETA
grid, you will see that the grid colums do not follow a longitude line
since the grid is not a lat/lon projection. I have attatched a gif image 
showing the region of the eta grid in question for you.

The way to fix you script is to ensure that the eastern pont of
your cxstns parameter is within the grid point domain, eg:
CXSTNS   = 30;-100>30;-62
CXSTNS   = 20;-100>20;-64
etc.,

or use -65 as the eastern extent for all your cross section latitudes.


Steve Chiswell
Unidata User Spport







> >From: "J. Correia" <address@hidden>
> >Organization: UCAR/Unidata
> >Keywords: 200008111524.e7BFOmN29681
> 
> >  This message is in MIME format.  The first part should be readable text,
> >  while the remaining parts are likely unreadable without MIME-aware tools.
> >  Send mail to address@hidden for more info.
> >
> >---559023410-851401618-966007460=:13009
> >Content-Type: TEXT/PLAIN; charset=US-ASCII
> >
> >hello again....i checked the grid and used the cursor command and its in
> >the domain...i must be making a mistake...
> >GRID NAVIGATION: 
> >     PROJECTION:          LCC                 
> >     ANGLES:                25.0   -95.0    25.0
> >     GRID SIZE:           93  65
> >     LL CORNER:              12.19   -133.46
> >     UR CORNER:              57.29    -49.38
> >
> > GRID ANALYSIS BLOCK: 
> >     ANALYSIS TYPE:        BARNES
> >     DELTAN:               4.000
> >     DELTAX:           -9999.000
> >     DELTAY:           -9999.000
> >     GRID AREA:            11.00 -154.00   62.00  -48.00
> >     EXTEND AREA:          11.00 -154.00   62.00  -48.00
> >     DATA AREA:            11.00 -154.00   62.00  -48.00
> >ive included the script that im running...its not pretty but it works.
> >thanks for the help.
> >jimmyc
> >
> >On Thu, 10 Aug 2000, Unidata Support wrote:
> >
> >> >From: "J. Correia" <address@hidden>
> >> >Organization: UCAR/Unidata
> >> >Keywords: 200008101938.e7AJcGT15344
> >> 
> >> >
> >> >
> >> >---------- Forwarded message ----------
> >> >Date: Thu, 10 Aug 2000 15:35:28 -0400 (EDT)
> >> >From: J. Correia <address@hidden>
> >> >To: address@hidden
> >> >Subject: gdcross prob
> >> >
> >> >hello,
> >> >im having a problem with gdcross...im using an eta file from jan 2000...
> >> >gempak refuses to plot a cross section lower than 34 degrees
> >> >latitude...but the dataset says that the limits are 11 to 62 degrees on
> >> >the analysis and 12 to 57 on the projection...(i obtained those from
> >> >gdinfo) ...any idea whats happening?
> >> >james correia jr.
> >> >fsu
> >> >
> >> >
> >> >
> >> 
> >> James,
> >> 
> >> The ETA grid is a lambert conformal projection, so the grid rows
> >> appear curved if you were to plot if on a straight CED projection.
> >> You probably need to ensure that your cross section axis is within
> >> the data domain.
> >> 
> >> Try plotting the grid with gdmap. Ensure that your cxstns input is
> >> within the data domain (you can use to gempak command "cursor cxstns"
> >> to set your starting and endpoints from your cursor).
> >> 
> >> If you cannot get this to work, please send me you parameter settings
> >> for gdcross, and your projection info from gdinfo.
> >> 
> >> Steve Chiswell
> >> ****************************************************************************
> >> Unidata User Support                                    UCAR Unidata 
> >> Program
> >> (303)497-8644                                                  P.O. Box 
> >> 3000
> >> address@hidden                                   Boulder, CO 80307
> >> ----------------------------------------------------------------------------
> >> Unidata WWW Service                        http://www.unidata.ucar.edu/    
> >>  
> >> ****************************************************************************
> >> 
> >
> 
> 

Attachment: eta.gif
Description: ETA grid