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GDCFIL is typically used when the user has some knowledge about the data that will be gridded, and is experienced in the selection of the Barnes Analysis parameteres. The program OAGRID is designed to query that data that will be gridded, and suggest reasonable values for the parameters used in Barnes Analysis, which if accepted will be used to create the grid file.
Grid files may also be created by using information in existing grid files and copying the navigation and analysis parameters to the newly generated grid file.
GDFILE new grid file name DELTAN 0 station spacing DELTAX 0 grid spacing DELTAY 0 GRDAREA output grid region EXTEND 2;2;2;2 extra grid rows for first pass DTAAREA Data area for OA blank uses EXTEND area SOURCE data source (SN or SF) SNFILE sounding data input file SFFILE surface data input file SNPARM Sounding parameter list SFPARM Surface parameter list DATTIM Date/time LEVELS Levels to search MAXGRD Maximum number of grids in output file
The computed station spacing DELTAN is the average of the computed and uniform station spacing. This spacing will be used in the Barnes Analysis routines to determine the search radius also known as the radius of influence. A default value of 0 should be used for OAGRID to compute and select its own value. The value of DELTAN is used with the selected grid region to compute DELTAX and DELTAX. If values are given for DELTAN, DELTAX, and DELTAY, OAGRID will accept those values for the grid.
The EXTEND area is the number of grid rows to extend the GRDAREA for the first pass of the Barnes analysis. The purpose of extending the desired grid area is to reduce the edge effects. DTAAREA is the region in which station data is considered.
OAGRID produces evenly spaced lat/lon (CED) grids. For greater flexibility in choosing the projection, GDCFIL may be used.
New Variables
KXKY The number of X;Y grid points
CPYFIL Used to copy grid file information from an existing
grid file. Other variables are ignored if CPYFIL
is not blank.
ANLYSS DELTAN / EXTEND
If the DELTAN field in ANLYSS is left blank, the DELTAN values is assigned as twice the grid spacing computed from the gridarea and KXKY.
CPYFIL can be used to transfer the grid information from an existing file, or to generate a grid based on one of the known grids in the grid navigation table used for model grids.
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