get_target_gridsize

 PURPOSE:  calculate coordinate vectors and target grid size for a grid to
           be resampled to a new cellsize .
 -------------------------------------------------------------------------
 USAGE: [nx,ny,newgrid] = get_target_gridsize(xll, yll, cols,rows,cellsize,targetcellsize);
 where: 
        [xll,yll] are the coordinates of the lower left corner of the input grid
        [cols],[rows] are the number of columns and rows of the existing
        grid
        [cellsize] is the current cellsize of the original grid
        [targetcellsize] is the target cellsize the grid is resampled to
 -------------------------------------------------------------------------
 OUTPUTS:
        [nx],[ny] are the x and y coordinate vectors of the new resampled
        grid
        [newgrid] is a matrix with cols and rows according to the new
        cellsize 
 -------------------------------------------------------------------------
 NOTES: All coordinates used are lower left corner coordinates! New matrix
        has no of rows and cols that sum up to either same size or less than
        original grid. If extent does not match, rows and cols are rounded
        down. Couting from llc.

 Felix Hebeler, Geography Dept., University Zurich, March 2006.

0001 function [nx,ny,newgrid] = get_target_gridsize(xll, yll, cols,rows,cellsize,targetcellsize);
0002 
0003 % PURPOSE:  calculate coordinate vectors and target grid size for a grid to
0004 %           be resampled to a new cellsize .
0005 % -------------------------------------------------------------------------
0006 % USAGE: [nx,ny,newgrid] = get_target_gridsize(xll, yll, cols,rows,cellsize,targetcellsize);
0007 % where:
0008 %        [xll,yll] are the coordinates of the lower left corner of the input grid
0009 %        [cols],[rows] are the number of columns and rows of the existing
0010 %        grid
0011 %        [cellsize] is the current cellsize of the original grid
0012 %        [targetcellsize] is the target cellsize the grid is resampled to
0013 % -------------------------------------------------------------------------
0014 % OUTPUTS:
0015 %        [nx],[ny] are the x and y coordinate vectors of the new resampled
0016 %        grid
0017 %        [newgrid] is a matrix with cols and rows according to the new
0018 %        cellsize
0019 % -------------------------------------------------------------------------
0020 % NOTES: All coordinates used are lower left corner coordinates! New matrix
0021 %        has no of rows and cols that sum up to either same size or less than
0022 %        original grid. If extent does not match, rows and cols are rounded
0023 %        down. Couting from llc.
0024 %
0025 % Felix Hebeler, Geography Dept., University Zurich, March 2006.
0026 
0027         ncols = floor(cols*cellsize/targetcellsize);
0028         nrows = floor(rows*cellsize/targetcellsize);
0029         newgrid = zeros(nrows, ncols);
0030 
0031         % construct index vectors of llc coords
0032         nx = xll + [0:targetcellsize:(ncols-1)*targetcellsize];
0033         ny = yll + [0:targetcellsize:(nrows-1)*targetcellsize];