heat map source code for ThinkSpeak IoT analysis

heatmap.mat

% Enter your MATLAB code below
strength = thingSpeakRead(CHANNEL_ID, '{CHANNEL ID}',READ_API_KEY,'{READ_API_KEY}',1,'fields',[1]);
% Indoor position
X = [10 550 550 10 50 234 393 129 237 328 448 225 344 457 477]';
Y = [10 10 410 410 293 210 202 132 130 142 141 272 268 274 200]';
strengthPercent = 2*(strength+100)/100;
picture = imread('https://{}.png');
[height,width,depth] = size(picture);
OverlayImage=[];
F = scatteredInterpolant(Y, X, strengthPercent,'linear');
for i = 1:height-1
   for j = 1:width-1
          OverlayImage(i,j) = F(i,j);
   end
end
alpha = (~isnan(OverlayImage))*0.6;

imshow(picture);
hold on
OverlayImage = imshow( OverlayImage );
caxis auto  
colormap( OverlayImage.Parent, jet );
colorbar( OverlayImage.Parent );
set( OverlayImage, 'AlphaData', alpha );