function [h]=pltmask(Gname,ptype,C);

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Hernan G. Arango %%%%
% Copyright (c) 2001 Rutgers University.                               %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                                                      %
% function [h]=pltmask(Gname,C);                                       %
%                                                                      %
% This function plots the land/sea mask. If appropriate, It also       %
% ovelays the given coastline data.                                    %
%                                                                      %
%                                                                      %
% On Input:                                                            %
%                                                                      %
%    Gname       NetCDF file name (character string).                  %
%    ptype       plot type flag:                                       %
%                  ptype=0   => Cartesian axis.                        %
%                  ptype=1   => Spehrical axis.                        %
%    C           Coastline indices (structure array):                  %
%                  C.grid    => Grid file name.                        %
%                  C.coast   => Coastline file name.                   %
%                  C.indices => Coastline indices file name.           %
%                  C.lon     => Coastline longitudes.                  %
%                  C.lat     => Coastline latitudes.                   %
%                  C.Icst    => Coastline I-grid coordinates, (0:L).   %
%                  C.Jcst    => Coastline J-grid coordinates, (0:M).   %
%                                                                      %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%  Read spherical switch.

spherical=0;
string=nc_read(Gname,'spherical');
if (upper(string) == 'T'),
  spherical=1;
end,

%  Set coastline switch

ICOAST=0;
if (spherical & (nargin >2)),
  ICOAST=1;
end,

%-----------------------------------------------------------------------
% Plot mask of PSI-points.
%-----------------------------------------------------------------------

figure;
mask=nc_read(Gname,'mask_psi');
[L,M]=size(mask);
if (spherical),
  lon=nc_read(Gname,'lon_psi');
  lat=nc_read(Gname,'lat_psi');
end,
[x,y]=ndgrid(1:L,1:M);
cmask=mask*2+mod(mod(x,2)+mod(y,2),2);

if (ptype & spherical),
  h=surface(lon,lat,cmask); shading flat;
  colormap([0 1 0;.5 1 0;0 .7 1;.3 0 1]);
  set(gca,'layer','top');
  axis tight;
  grid on;
  hold on
  plot(C.lon,C.lat,'k');
  xlabel('Longitude');
  ylabel('Latitude');
else,
  x=1:1:L; x=x';
  y=1:1:M;
  h=image(x,y,cmask','cdatamapping','scaled');
  colormap([0 1 0;.5 1 0;0 .7 1;.3 0 1]);
  set(gca,'YDir','normal','drawmode','fast','layer','top');
  grid on;
  hold on
  plot(C.Icst,C.Jcst,'k');
  xlabel('I-grid');
  ylabel('J-grid');
end,
title('Land/Sea Mask of PSI-points');

%-----------------------------------------------------------------------
% Plot mask of RHO-points.
%-----------------------------------------------------------------------

figure;
mask=nc_read(Gname,'mask_rho');
[Lp,Mp]=size(mask);
if (spherical),
  lon=nc_read(Gname,'lon_rho');
  lat=nc_read(Gname,'lat_rho');
end,
[x,y]=ndgrid(1:Lp,1:Mp);
cmask=mask*2+mod(mod(x,2)+mod(y,2),2);

if (ptype & spherical),
  h=surface(lon,lat,cmask); shading flat;
  colormap([0 1 0;.5 1 0;0 .7 1;.3 0 1]);
  set(gca,'layer','top');
  axis tight;
  grid on;
  hold on
  plot(C.lon,C.lat,'k');
  xlabel('Longitude');
  ylabel('Latitude');
else,
  x=0:1:Lp-1; x=x';
  y=0:1:Mp-1;
  h=image(x,y,cmask','cdatamapping','scaled');
  colormap([0 1 0;.5 1 0;0 .7 1;.3 0 1]);
  set(gca,'YDir','normal','drawmode','fast','layer','top');
  grid on;
  hold on
  plot(C.Icst,C.Jcst,'k');
  xlabel('I-grid');
  ylabel('J-grid');
end,
title('Land/Sea Mask of RHO-points');

%-----------------------------------------------------------------------
% Plot mask of U-points.
%-----------------------------------------------------------------------

figure;
mask=nc_read(Gname,'mask_u');
[L,Mp]=size(mask);
if (spherical),
  lon=nc_read(Gname,'lon_u');
  lat=nc_read(Gname,'lat_u');
end,
[x,y]=ndgrid(1:L,1:Mp);
cmask=mask*2+mod(mod(x,2)+mod(y,2),2);

if (ptype & spherical),
  h=surface(lon,lat,cmask); shading flat;
  colormap([0 1 0;.5 1 0;0 .7 1;.3 0 1]);
  set(gca,'layer','top');
  axis tight;
  grid on;
  hold on
  plot(C.lon,C.lat,'k');
  xlabel('Longitude');
  ylabel('Latitude');
else,
  x=1:1:L; x=x';
  y=0:1:Mp;
  h=image(x,y,cmask','cdatamapping','scaled');
  colormap([0 1 0;.5 1 0;0 .7 1;.3 0 1]);
  set(gca,'YDir','normal','drawmode','fast','layer','top');
  grid on;
  hold on
  plot(C.Icst,C.Jcst,'k');
  xlabel('I-grid');
  ylabel('J-grid');
end,
title('Land/Sea Mask of U-points');

%-----------------------------------------------------------------------
% Plot mask of V-points.
%-----------------------------------------------------------------------

figure;
mask=nc_read(Gname,'mask_v');
[Lp,M]=size(mask);
if (spherical),
  lon=nc_read(Gname,'lon_v');
  lat=nc_read(Gname,'lat_v');
end,
[x,y]=ndgrid(1:Lp,1:M);
cmask=mask*2+mod(mod(x,2)+mod(y,2),2);

if (ptype & spherical),
  h=surface(lon,lat,cmask); shading flat;
  colormap([0 1 0;.5 1 0;0 .7 1;.3 0 1]);
  set(gca,'layer','top');
  axis tight;
  grid on;
  hold on
  plot(C.lon,C.lat,'k');
  xlabel('Longitude');
  ylabel('Latitude');
else,
  x=0:1:Lp; x=x';
  y=1:1:M;
  h=image(x,y,cmask','cdatamapping','scaled');
  colormap([0 1 0;.5 1 0;0 .7 1;.3 0 1]);
  set(gca,'YDir','normal','drawmode','fast','layer','top');
  grid on;
  hold on
  plot(C.Icst,C.Jcst,'k');
  xlabel('I-grid');
  ylabel('J-grid');
end,
title('Land/Sea Mask of V-points');

return