[Dart-dev] [4480] DART/trunk/models/wrf/matlab/get_var_grid.m: Reads the grid information for a variable from either a WRF netcdf file

[nancy at ucar.edu]

Revision: 4480
Author:   thoar
Date:     2010-08-23 13:47:18 -0600 (Mon, 23 Aug 2010)
Log Message:
-----------
Reads the grid information for a variable from either a WRF netcdf file
or a DART netcdf - as soon as the DART netcdf variables have the 
"MemoryOrder" and "coordinates" attributes.

Added Paths:
-----------
    DART/trunk/models/wrf/matlab/get_var_grid.m

-------------- next part --------------
Added: DART/trunk/models/wrf/matlab/get_var_grid.m
===================================================================
--- DART/trunk/models/wrf/matlab/get_var_grid.m	                        (rev 0)
+++ DART/trunk/models/wrf/matlab/get_var_grid.m	2010-08-23 19:47:18 UTC (rev 4480)
@@ -0,0 +1,128 @@
+function output = get_var_grid(fname, varname)
+%% get_var_grid gets the grid variables for a given WRF variable.
+%
+% Example using a DART file: 
+% fname      = 'Prior_Diag.nc';
+% varname    = 'U_d01';
+%
+% mygrid = get_var_grid(fname, varname);
+%
+% Example using a WRF file: 
+% fname      = 'wrfinput_d01';
+% varname    = 'U';
+%
+% mygrid = get_var_grid(fname, varname);
+
+
+%% DART software - Copyright \xA9 2004 - 2010 UCAR. This open source software is
+% provided by UCAR, "as is", without charge, subject to all terms of use at
+% http://www.image.ucar.edu/DAReS/DART/DART_download
+%
+% <next few lines under version control, do not edit>
+% $URL$
+% $Id$
+% $Revision$
+% $Date$
+
+%% Copy the global attributes of interest
+filename    = fname;
+varname     = varname;
+memoryorder = deblank(nc_attget(fname,varname,'MemoryOrder'));
+
+if (exist(fname,'file') ~= 2)
+   error('%s does not exist',fname)
+end
+
+if (nc_isvar(fname,varname) ~= 1 )
+   error('%s does not exist in %s',varname,fname)
+end
+
+bob      = nc_info(fname);
+DARTfile = -1;
+
+%% Look for a telltale DART attribute to determine DART file or WRF file.
+
+for i = 1:length(bob.Attribute)
+   if (strcmpi(bob.Attribute(i).Name, 'model'))
+       DARTfile               = 1;
+       Zname         = 'ZNU_d01';
+       Zname_stag    = 'ZNW_d01';
+       Zdimname      = 'bottom_top_d01';
+       Zdimname_stag = 'bottom_top_stag_d01';
+       break
+   else
+       Zname         = 'ZNU';
+       Zname_stag    = 'ZNW';
+       Zdimname      = 'bottom_top';
+       Zdimname_stag = 'bottom_top_stag';
+   end
+end
+
+x = nc_getdiminfo(fname,Zdimname);      bottom_top      = x.Length;
+x = nc_getdiminfo(fname,Zdimname_stag); bottom_top_stag = x.Length;
+
+%% Get the variable information so we can query the dimensions etc.
+
+varinfo = nc_getvarinfo(filename, varname);
+
+switch lower(memoryorder)
+case '0'   % Time
+   error('unsupported storage order (%s) for %s',memoryorder, varname)
+
+case 'z'   % Time, bottom_top
+   error('unsupported storage order (%s) for %s',memoryorder, varname)
+   
+case 'xy'  % Time, south_north, west_east
+   coordinates     = nc_attget(fname, varname, 'coordinates');
+   bob             = strread(coordinates,'%s');
+   output.xvarname = char(bob(1,:));
+   output.yvarname = char(bob(2,:));
+   output.xvar     = nc_varget(fname, output.xvarname);
+   output.yvar     = nc_varget(fname, output.yvarname);
+   
+case 'xyz' % .... you get the picture
+   coordinates     = nc_attget(fname, varname, 'coordinates');
+   bob             = strread(coordinates,'%s');
+   output.xvarname = char(bob(1,:));
+   output.yvarname = char(bob(2,:));
+
+   % WRF doesn't provide the same mechanism for a Z coordinate
+   % find dimension index for vert
+   bob = strfind(lower(varinfo.Dimension), 'bottom') ;
+   zindex = -1;
+   for i = 1:length(bob)
+      if ( bob{i} == 1 )
+         zindex = i;
+         output.zdimname = varinfo.Dimension{i};
+         output.zdimsize = varinfo.Size(i);
+      end
+   end
+   if (zindex < 0) 
+      error('dagnabbit')
+   end
+   if (    output.zdimsize == bottom_top )
+           output.zvarname =  Zname;
+   elseif (output.zdimsize == bottom_top_stag )
+           output.zvarname =  Zname_stag;
+   else
+       error('gollygoshdagnabbit')
+   end
+
+   output.xvar      = nc_varget(fname,output.xvarname);
+   output.yvar      = nc_varget(fname,output.yvarname);
+   output.zvar      = nc_varget(fname,output.zvarname);
+   
+otherwise
+   error('unknown storage order (%s) for %s',memoryorder, varname)
+end
+
+inds              = output.xvar < 0;
+output.xvar(inds) = output.xvar(inds) + 360;
+output.minlon     = min(output.xvar(:));
+output.maxlon     = max(output.xvar(:));
+
+%% Set the latitude limits - must check for southern hemisphere
+
+absmin            = min(abs(output.yvar(:)));
+output.minlat     = min(output.yvar(:));
+output.maxlat     = max(output.yvar(:));


Property changes on: DART/trunk/models/wrf/matlab/get_var_grid.m
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Added: svn:mime-type
   + text/x-matlab
Added: svn:keywords
   + Date Rev Author HeadURL Id
Added: svn:eol-style
   + native