if you start the arduino IDE and open the monitor you see what is send and how often,
delay(2000); at the beginning
+
delay(500); at the end
might be 2 records in 5 second,
and my graph is width - 2 * 5 = 790 pix
then it starts at the beginning
if the values are already in 90,57 degC and not 745 of 1023 Ain
you need first to convert from string to FLOAT, not INT
and must find a new ranging in each map to make it for 100pix line range
ok, you convert from float to int and send ( very bad resolution ) so
string to int
is OK
range up to you