find_nearest_pt

 Find nearest point in Mesh structure to (x,y) 

 function [Point,Distance] = find_nearest_pt(xloc,yloc,Mobj) 

 DESCRIPTION:
    Find nearest point to (xloc,yloc) in the domain of Mobj
    using native coordinates of Mobj

 INPUT:
   xloc   = x location of point (in native Mobj coordinates)
   yloc   = y location of point (in native Mobj coordinates)
   Mobj   = Mesh object with the following fields:
               - nativeCoords = grid type (cartesian or spherical)
               - x, y and/or lon, lat = coordinates (dependent on
               nativeCoords).

 OUTPUT:
   Point = index of nearest vertex in the mesh
   Distance = Distance from x,y to Point in Mobj native coordinates

 EXAMPLE USAGE
    [Point,Distance] = find_nearest_point(50.1,100.2,Mobj)

 Author(s):  
    Geoff Cowles (University of Massachusetts Dartmouth)
    Pierre Cazenave (Plymouth Marine Laboratory)

 Revision history
    2015-01-14 Tidy up the code a bit and add extra information to the
    help.

==============================================================================

0001 function [Point,Distance] = find_nearest_pt(xloc,yloc,Mobj) 
0002 % Find nearest point in Mesh structure to (x,y)
0003 %
0004 % function [Point,Distance] = find_nearest_pt(xloc,yloc,Mobj)
0005 %
0006 % DESCRIPTION:
0007 %    Find nearest point to (xloc,yloc) in the domain of Mobj
0008 %    using native coordinates of Mobj
0009 %
0010 % INPUT:
0011 %   xloc   = x location of point (in native Mobj coordinates)
0012 %   yloc   = y location of point (in native Mobj coordinates)
0013 %   Mobj   = Mesh object with the following fields:
0014 %               - nativeCoords = grid type (cartesian or spherical)
0015 %               - x, y and/or lon, lat = coordinates (dependent on
0016 %               nativeCoords).
0017 %
0018 % OUTPUT:
0019 %   Point = index of nearest vertex in the mesh
0020 %   Distance = Distance from x,y to Point in Mobj native coordinates
0021 %
0022 % EXAMPLE USAGE
0023 %    [Point,Distance] = find_nearest_point(50.1,100.2,Mobj)
0024 %
0025 % Author(s):
0026 %    Geoff Cowles (University of Massachusetts Dartmouth)
0027 %    Pierre Cazenave (Plymouth Marine Laboratory)
0028 %
0029 % Revision history
0030 %    2015-01-14 Tidy up the code a bit and add extra information to the
0031 %    help.
0032 %
0033 %==============================================================================
0034 
0035 % global ftbverbose
0036 subname = 'find_nearest_pt';
0037 % if ftbverbose
0038 %     fprintf('\nbegin : %s\n', subname)
0039 % end
0040 
0041 %------------------------------------------------------------------------------
0042 % Parse input arguments
0043 %------------------------------------------------------------------------------
0044 if ~exist('xloc', 'var') || ~exist('yloc', 'var') || ~exist('Mobj', 'var')
0045     error('arguments to %s are missing', subname)
0046 end
0047 
0048 %------------------------------------------------------------------------------
0049 % Set native coordinates
0050 %------------------------------------------------------------------------------
0051 if strcmpi(Mobj.nativeCoords, 'cartesian')
0052     x = Mobj.x;
0053     y = Mobj.y;
0054 elseif strcmpi(Mobj.nativeCoords, 'spherical')
0055     x = Mobj.lon;
0056     y = Mobj.lat;
0057 else
0058     error('Unrecognised coordinate type.')
0059 end
0060 
0061 %------------------------------------------------------------------------------
0062 % Find the nearest point
0063 %------------------------------------------------------------------------------
0064 [Distance, Point] = min(sqrt((xloc - x).^2 + (yloc - y).^2));
0065 
0066 % if ftbverbose
0067 %     fprintf(['end   : ' subname '\n'])
0068 % end
0069 
0070