Summing up two graphs with different starting point

Hey Matlab Community,

I have two graphs as seen from the figure below and I need to sum them up.

For the graph I have 4 separate column vectors. So for Red I have two separate column vectors with X and Y values and similarly for Blue I have two separate X and Y values The challenge is they both start from different point. The Red one starts at 25C and the Blue one starts at 170C. How can I plot the sum of graphs ? ( Just to clarify the resulting graph should be exactly equal to red graph until 170C and then it would start to deviate because of the addition of Blue.)

I hope I managed to explain the challenge I am facing. Any help would be greatly appreciated.

Thanks and Greetings

Kush

Answer 1

[ANKUR KUMAR]

Method 1: Using boolean

clc
clear
YY=rand(151,2);
XX=[[50:5:800]' [175:5:925]']
data=[XX(:,1) YY(:,1) XX(:,2) YY(:,2)]

plot(data(:,1), data(:,2),'k');
hold on
plot(data(:,3), data(:,4),'b');


uniq=unique([data(:,1);data(:,3)]);

for kk=1:length(uniq)
	index1=find(data(:,1)==uniq(kk));
	if ~isempty(index1)
		value1(kk)=data(index1,2);
	else
		value1(kk)=nan;
	end
	
	index2=find(data(:,3)==uniq(kk))
	
	if ~isempty(index2)
		value2(kk)=data(index2,4);
	else
		value2(kk)=nan;
	end
end
hold on
plot(uniq,value1+value2,'r')

Method 2: Interpolation

clc
clear
% generating random data
YY=rand(151,2);
XX=[[50:5:800]' [175:5:925]']
data=[XX(:,1) YY(:,1) XX(:,2) YY(:,2)]

plot(data(:,1), data(:,2),'k');
hold on
plot(data(:,3), data(:,4),'b');

uniq=unique([data(:,1);data(:,3)]);
value1=interp1(data(:,1),data(:,2),uniq);
value2=interp1(data(:,3),data(:,4),uniq);
plot(uniq,value1+value2,'r')

[Kushagra Mehrotra]

Ohh wow, this is incredible !

Thank you so much for taking time out and writing a code to help me, you are a saviour ! I will try to run the code and Accept the answer ASAP. Again thanks for the time you took to formulate that !