SN=tgeocode(TX,TY,FX1,FY1,FX2,FY2,FX3,FY3,SN,stammname,stammpfad)

function SN=tgeocode(TX,TY,FX1,FY1,FX2,FY2,FX3,FY3,SN,stammname,stammpfad)

% function SN=tgeocode(TX,TY,FX1,FY1,FX2,FY2,FX3,FY3,SN,stammname,stammpfad)
%
% Geocoding with on Screen Digitizing using affine and projective Transformation
% - Digitizing the New Points, Transformation of the der New Points
%
% 19.02.03 Markus Penzkofer

global HFG
global HE_TRAFO
global HA_NN HA_SN
global STATUS

% Control of the Status
if (STATUS < 1)
  disp('Please load data first!');
  set(HFG,'Name','MATLAB DIGITIZER: Please load data first!');
  return;
end
if (STATUS < 2)
  disp('Please digitize Control Points first!');
  set(HFG,'Name','MATLAB DIGITIZER: Please digitize Control Points first!');
  return;
end
if (STATUS < 3)
  disp('Please compute Transformation Parameters first!');
  set(HFG,'Name','MATLAB DIGITIZER: Please compute Transformation Parameters first!');
  return;
end


% File: New Points
neuname = [stammname '_new.mdg'];

% File: transformed New Points
ntrname = [stammname '_ntr.mdg'];

% Digitizing: New Points
disp('Digitize New Points and end with Return Button!');
set(HFG,'Name','MATLAB DIGITIZER: Digitize New Points and end with Return Button!');
figure(HFG);
[xnd,ynd] = ginput;
set(gca,'Layer','top')
hold on
plot(xnd,ynd,'co');

% Save: digitized New Points
eval(['cd ' stammpfad]);
if (STATUS == 3)
  [neufid,mess] = fopen(neuname,'w');
elseif (STATUS == 4)
  [neufid,mess] = fopen(neuname,'a');
  fprintf(neufid,'NaN NaN\n');
end
if (neufid == -1)
  disp(['  ! File ' stammpfad  neuname ' cannot be opened.']);
  error(mess);
end   
disp(['   < Output File ' stammpfad  neuname ' opened.']);
for i=1:length(xnd)
  fprintf(neufid,'%f %f\n', xnd(i), ynd(i));
end

% Number of New Points
NN = length(xnd);

% Initialization
YN = zeros(1,NN);
XN = zeros(1,NN);
YNZ = zeros(1,NN);
XNZ = zeros(1,NN);

% Transformation Type
trafo = get(HE_TRAFO,'Value');

if (trafo == 1)

  % AFFINE TRANSFORMATION: Transformation of the New Points
  XO = TX;
  YO = TY;
  DX = FX1;
  CX = FY1;
  CY = FX2;
  DY = FY2;
  for S = 1:NN
    YN(S) = ynd(S);
    XN(S) = xnd(S);
    YNZ(S) = YO + CY * XN(S) + DY * YN(S);
    XNZ(S) = XO + DX * XN(S) + CX * YN(S);
  end

else

  % PROJECTIVE TRANSFORMATION: Transformation of the New Points
  c1 = TX;
  c2 = TY;
  a1 = FX1;
  b1 = FY1;
  a2 = FX2;
  b2 = FY2;
  a3 = FX3;
  b3 = FY3;
  for S = 1:NN
    YN(S) = ynd(S);
    XN(S) = xnd(S);
    YNZ(S) = (a2 * XN(S) + b2 * YN(S) + c2)/(a3 * XN(S) + b3 * YN(S) + 1);
    XNZ(S) = (a1 * XN(S) + b1 * YN(S) + c1)/(a3 * XN(S) + b3 * YN(S) + 1);
  end

end
 
xnt = XNZ;
ynt = YNZ;

% Save: transformed the New Points
eval(['cd ' stammpfad]);
if (STATUS == 3)
  [ntrfid,mess] = fopen(ntrname,'w');
elseif (STATUS == 4)
  [ntrfid,mess] = fopen(ntrname,'a');
  fprintf(ntrfid,'NaN NaN\n');
end
if (ntrfid == -1)
  disp(['  ! File ' stammpfad  ntrname ' cannot be opened.']);
  error(mess);
end   
disp(['   < Output File ' stammpfad  ntrname ' opened.']);
for i=1:length(xnt)
  fprintf(ntrfid,'%f %f\n', xnt(i), ynt(i));
end

fclose('all');

SN = SN + NN;
set(HA_NN,'String',num2str(NN));
set(HA_SN,'String',num2str(SN));
disp('New Points transformed und saved!');
set(HFG,'Name','MATLAB DIGITIZER: New Points transformed und saved!');

% Status
STATUS = 4;