how to scale values while plotting graphs in matlab

in my program i have to read a variable from an excel sheet of size 3600sec*24hrs.(column wise)

GDOP1=[]
GDOP=xlsread('positions.xlsx','GDOP'); => size=3600*24
for j=1:1
    GDOP1=[GDOP1 GDOP(j:end)] =>size=1*86400(i.e one day data in sec)
end

now my problem is to plot this data(GDOP1) on y-axis against time on x axis in the form of 0 to 24hrs rather than from 0 to 86400 seconds

[Star Strider]

It appears that you have data collected every second for 24 hours.

What do you mean by ‘scale this data(GDOP1) from 0 to 24hrs’. How do you want to ‘scale’ it?

[Divya]

while plotting i want x axis in hrs rather than seconds

[Image Analyst]

How are you plotting it? Which variable, or column, is x and which is y?

[Divya]

GDOP1(of size 1*86400) should be plotted on y axis and time on x axis the thing is time is in seconds but i would like it to scale down to hours

[Image Analyst]

That didn't answer a single one of my questions. I was expecting something like "the y values are in column 2 of GDOP1, and the x values are in column 1 but are in units of seconds instead of hours like I want. I'm plotting them like this

x = GDOP1(:, 1);
y = GDOP1(:, 2);
plot(x, y, 'b-');

Now, can you try again? Or, for bonus points, attach your workbook?

[Divya]

in workbook i have only gdop values read for 24hrs such that each column represents 1 hour data and each block in that column is the gdop value for a sec

Answer 1

[Star Strider]

This seems close to what you want to do:

sec = [1:86400]';                                   % Time In Seconds
GDOP1 = 0.1*randn(86400, 1) - cos(2*pi*sec/86400);  % Create Data

hrs = sec/(60*60);                                  % Convert Seconds To Hours

figure(1)
plot(hrs, GDOP1)
grid