gridvecs

clear all; close all;
gridfile = '~gcowles/Data/NOAA_MITSG_TKE/mtm1b.nc';
x1 = 836100;
x2 = 935370;
y1 = -186230;
y2 = -125810;
ds = 2000;
fname = 'mtm1b_2km_nansound_vecs.dat';

0001 function gridvecs(gridfile,x1,x2,y1,y2,ds,thresh,fname)
0002 
0003 %clear all; close all;
0004 %gridfile = '~gcowles/Data/NOAA_MITSG_TKE/mtm1b.nc';
0005 %x1 = 836100;
0006 %x2 = 935370;
0007 %y1 = -186230;
0008 %y2 = -125810;
0009 %ds = 2000;
0010 %fname = 'mtm1b_2km_nansound_vecs.dat';
0011 
0012 % Find elements closest to a grid of points for cleaning up vector plots
0013 %
0014 % function [] = gridvecs(fname,x2,y1,y2,ds)
0015 %
0016 % DESCRIPTION:
0017 % Find elements closest to a grid of points for cleaning up vector plots
0018 %
0019 % INPUT:
0020 %    gridfile:  FVCOM netcdf output file containing x,y
0021 %    fname:  list of node numbers
0022 %    x1:  left side of bounding box
0023 %    x2:  right side of bounding box
0024 %    y1:  bottom of bounding box
0025 %    y2:  top of bounding box
0026 %    ds:  grid lengthscale
0027 %    thresh: threshold distance in units of x.  If nearest FVCOM point to the
0028 %            vector grid is greater than this distance, no point is assigned.
0029 %
0030 % OUTPUT:
0031 %    fname: file containing indices of node numbers where vectors should be plot
0032 %
0033 % Author(s):
0034 %    Geoff Cowles (University of Massachusetts Dartmouth)
0035 %
0036 % References
0037 %==============================================================================
0038 
0039 
0040 % open grid file and read data
0041 if(~exist(gridfile))
0042   error('grid file does not exist')
0043 end;
0044 
0045 nc = netcdf(gridfile);
0046 x  = nc{'x'}(:);
0047 y  = nc{'y'}(:);
0048 nVerts = numel(x);
0049 fprintf('number of nodes in the mesh %d\n',nVerts);
0050 nc = close(nc);
0051 
0052 % create the grid
0053 [X,Y] = meshgrid(x1:ds:x2,y1:ds:y2);
0054 [il,jl] = size(X);
0055 node = zeros(il*jl,1);
0056 cnt   = 0;
0057 for i=1:il
0058 for j=1:jl
0059    xloc = X(i,j); 
0060    yloc = Y(i,j);
0061    dist = sqrt(   (x-xloc).^2 + (y-yloc).^2);  
0062    [mind,imin] = min(dist);
0063    if(mind < thresh);  
0064      cnt = cnt + 1;
0065      node(cnt) = imin;
0066    end;
0067 end;
0068 end;
0069 node = node(1:cnt);  
0070 
0071 % dump the list
0072 fid = fopen(fname,'w');
0073 for i=1:cnt
0074   fprintf(fid,'%d\n',node(i));
0075 end;
0076 fclose(fid);