getMap.m

function [ Xz, Yz, Zz ] = getMap( strfile,box )
% GETMAP Gets a binary map as generated by mapbuilder
% [ Xb, Yb, Zb ] = GETMAP( strfile )
% Argument strfile is filename to read from. Zb = f( Xb, Yb ) is returned.
% box = [xmin xmax ymin ymax] all in meters for zoom around cross-point

  xmin = box(1);
  xmax = box(2);
  ymin = box(3);
  ymax = box(4);
  
  xmin = round(xmin/200);
  xmax = round(xmax/200);
  xmin = 1001+xmin;
  xmax = 1001+xmax;
  ymin = round(ymin/200);
  ymax = round(ymax/200);
  ymin = 1001+ymin;
  ymax = 1001+ymax;

  fid = fopen( strfile, 'rb' );
  if fid<0
      disp(sprintf('Error! Could not open map file %s!',strfile))
      return
  end
  nx = fread( fid, 1,   'int16' );
  ny = fread( fid, 1,   'int16' );
  dx = fread( fid, 1, 'float32' );
  dy = fread( fid, 1, 'float32' );
  x0 = fread( fid, 1, 'float32' );
  y0 = fread( fid, 1, 'float32' );
  Zb = zeros( ny, nx );
  for ky = 1:ny
    Zb( ky, : ) = fread( fid, nx, 'int16' )';
  end
  fclose( fid );
  Xb = x0 + dx*[ 0:(nx-1) ];
  Yb = y0 + dy*[ 0:(ny-1) ];
  
  %contourf(Xb,Yb,Zb)
%   if ymax<0 | xmax<0
%       Xz = 0;
%       Yz = 0;
%       Zz = 0;
%       return;
%   end
  Xz = Xb(xmin:xmax);
  Yz = Yb(ymin:ymax);
  Zz = Zb(ymin:ymax,xmin:xmax);
  %contourf(Xz,Yz,Zz,20)