%function burningsDetection
function bue

preband5 = imread("preB05.tiff"); %band5 (NIR)
preband7 = imread("preB07.tiff"); %band7 (SWIR)
postband5 = imread("postB05.tiff"); %band5
postband7 = imread("postB07.tiff"); %band7

pNIR_pre = double(preband5);
pSWIR_pre = double(preband7);
SWVI_pre = (pNIR_pre - pSWIR_pre)./(pNIR_pre + pSWIR_pre);

pNIR_post = single(postband5);
pSWIR_post = single(postband7);
SWVI_post = (pNIR_post- pSWIR_post)./(pNIR_post + pSWIR_post);

[n1, m1] = size(SWVI_pre); % n1 - stroki
[n2, m2] = size(SWVI_post); % m1 - stolbcy
if n1 ~= n2 || m1 ~= m2
  PP = checkIfEqual(SWVI_pre, n1, m1 SWVI_post, n2, m2);

  SWVI_pre = PP{1};
  SWVI_post = PP{2};
endif

DSWVI = SWVI_pre - SWVI_post;
  figure,
  imagesc(DSWVIC)
  %colorbar
  %colormap(jet)

print -dpng -r300 SWVI_pre_1346.png

%fire_calculate
end



function PP = checkIfEqual(pre, n1, m1 post, n2, m2)

  h = abs(n1-n2)
  w = abs(m1-m2)

  if n1 < n2
    post = post(1:n2-h, :);
    flag = 1;
  elseif n1 > n2
    pre = pre(1:n1-h, :);
    flag = 2;
  endif

  if m1 < m2
    post = post(:, m2:m2+w-1);
    flag = 3;
  elseif m1 > m2
    pre = pre(:, m1:m1+w-1);
    flag = 4;
  endif

  PP = {pre; post};

endfunction


function fire_calculate

Square = 76100;
pict = imread("kalmykia_fire.png");

[n, m] = size(pict);
all = n*m;
white = length(find(pict==255));
black = length(find(pict==0));
no_white = all - black - white;

fract = no_white/white;
Percent = fract*100;
Territory = Square*fract;
disp(Territory);

end