20020605: Color Fill Using oagrid/oabsfc/gdplot

Patrick,

OAGRID only creates CED gridsi and uses the mean station spacing calculated
from your data set. You can use GDCFIL to have more control
on the grid produced, including the grid area, projection, and
grid point spacing.

The problem with using OAGRID is that the mean station spacing for land stations
is significantly different than your ship/buoy data. The resulting grid point
spacing is likely too small for the ocean areas.

The SEARCH parameter in OABSFC using /EX will extrapolate where you don't have
at least 3 stations within the search radius, but your grid is probably
too fine over the area. In GDCFIL, decrease the number of X and Y grid points.

Another thing you can do to improve data void regions is to use the first guess
capability to create a zeroeth pass from one of the global grids.

Steve Chiswell
Unidata User SUpport

On Wed, 5 Jun 2002, Patrick O'Reilly wrote:

> Hello gembuds,
>
> I have a script to color contour surface temps using surface and ship/buoy 
> data.  My one problem is that there is no data in a certain spot I am mapping 
> (W of Baja California) and therefore no color fills are drawn.  What 
> parameters in either OAGRID or OABSFC may I adjust to help fill this spot?  
> What I have now is below:
>
> # Create the grid file for use in plotting surface isotherms #
>
> oagrid<< OAGRID_FLAG
> gdfile=sfctmp.grd
> deltan=1
> deltax=.5
> deltay=.5
> grdarea=15;-155;55;-55
> extend=4;4;4;4
> dtaarea=
> source=SF
> sffile=$sffile
> sfparm=tmpf
> dattim=$dattim
> levels=0
> maxgrd=200
>
> run
>
> exit
>
> OAGRID_FLAG
>
> # Run the Barnes analysis on the surface file #
>
> oabsfc<< OABSFC_FLAG
> sffile=$sffile+$sbfile
> gdfile=sfctmp.grd
> search=40/ex
> dtaarea=data
>
> run
>
> exit
>
> OABSFC_FLAG
>
>
> The output file is at:
>
> http://www.uni.edu/storm/wximages/images/f_ustemps.gif
>
> Thanks for any suggestions.
>
> Patrick
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Patrick O'Reilly                               Support Scientist
> The STORM Project            address@hidden
> 208 Latham Hall                             ph: 319-273-3789
> University of Northern Iowa
> Cedar Falls, IA 50614
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>