# Area under the curve with conditions?

14 views (last 30 days)
MUKESH KUMAR on 8 Aug 2019
Commented: Star Strider on 13 Sep 2019
I want to do following tasks,
First generate a time series load data between 550-1000 for one day 30 min interval, so is load(48*1) dataset
then set level_1 = 750 and draw a line on the graph,
then find out the area above this level_1 line and area under seprate level (lets say level_2 = 600) line seprately

Star Strider on 8 Aug 2019
Try this:
t = 1:48; % Time Vector
load = randi(1000, 1, 48); % Create Data
level_1 = 750;
level_2 = 600;
above_level_1 = load >= level_1; % Logical Index Vector
area_1 = trapz(t(above_level_1), load(above_level_1)); % Area Under ‘Level_1’
below_level_2 = load <= level_2; % Logical Index Vector
area_2 = trapz(t(below_level_2), load(below_level_2)); % Area Under ‘Level_2’
figure
hold on
plot(xlim, [1 1]*level_1)
plot(xlim, [1 1]*level_2)
hold off
grid

Star Strider on 20 Aug 2019
It is not obvious to me, either. Since your other Question got several views although no replies, it appears that others also could not solve it.
MUKESH KUMAR on 13 Sep 2019
How can I find the area above for level_1 for each two continuous time stamp like for example in figure(L1 is line of Level_1), find area seprate for each color code simillary for area below level_2. and after that how to find the sum of area for 1,(1+2), (1+2+3),(1+2+3+4),.....and so on strips....... Star Strider on 13 Sep 2019
Try this:
t = linspace(0, 24, 48); % Time Vector
load = 450*sin(2*pi*t/20)+550; % Create Data
level_1 = 750;
above_level_1 = load >= level_1; % Logical Index Vector
figure
hold on