Incorrect autoscaling during plot command in matlab

Hello guys, first time poster. I just had a question about my code- I am just trying to plot some data that I imported from a csv file, but the plot itself leaves voids.

I haven't done anything to change the settings.

The code:

clear all; close all; clc

t = load('sampledata.csv');
time=t(1:125000,1);
gage=t(1:125000,2);
plot(time,gage)
xlabel('Sample Number')
ylabel('volts')
title('{\bf Oscilloscope Data}')

below is the image i got from the plot. http://img220.imageshack.us/img220/4417/oscilloscope.jpg

any help or advice will be appreciated. thanks!

sam

[Fangjun Jiang]

What do you mean "the plot itself leaves voids"?

[Jan]

For "clear all" see this: http://www.mathworks.com/matlabcentral/answers/16484-good-programming-practice#answer_22301

Congratulations: You are a first time poster *and* formatted the code correctly *and* embedded a picture instead of posting just a link to it. Although I did not understand what the problem is, the layout is excellent. Therefore this is my personal *question of the week*. +1

[Walter Roberson]

@Jan: I reformatted the post and embedded the image...

[Samuel]

To all, thanks for the response! @walter- how did you manage to embed the image? I wasn't able to find the command to embed the image.

@fangjun- I actually mean't that the plot axes stretches, so to say, farther than the data needs. Especially if you see at -.5, there is an empty space where there are no values. Same follows for the top and bottom axes.

[Walter Roberson]

To embed an image, use a separate paragraph and start it with << followed immediately (no space after << ) by the URL to the image directly, followed immediately (no space after URL) by >>

The tricky part is often in finding the direct URL for the image, especially if you do not have an account on the system being used to host the image. For situations like that, I display the image in my browser, position my cursor over it, right-click, and choose "Copy image location". That URL is then the one I paste in to the posting.

Answer 1

[Bjorn Gustavsson]

That figure looks OK to me I guess. "Guess" since I dont know what your data going in was...

What points are you missing?

Do you want a tighter fit of the plot around the points? Then you should could do:

axis tight

Beside that not much to go on here.

HTH

[Jan]

I do not understand what should be wrong with the diagram also.

[Walter Roberson]

Perhaps the OP is not expecting the straight line of -10 values ?

Or perhaps the OP is expecting a solid outline instead of the high-frequency hopping?

Or perhaps the OP is referring to the parts that sort of look like black "diamonds"? Those might be seen as "holes", especially since there is no apparent reason for them to appear black instead of blue ?

[Samuel]

Sorry for not being so clear guys.

What I would like to have change from this plot will be so that the data axis will be from -10 to 10 on the y axis, and ~.4 to 2.5 for the x axis(just to encompass the data), automatically, after I plot.

This is probably a rather simple problem with a VERY easy solution- any help will be appreciated.

Thanks

Sam

[Fangjun Jiang]

axis([XMIN XMAX YMIN YMAX])

Answer 2

[Samuel]

Thanks Bjorn-

I actually tried "axis tight", and this ALMOST is what I need.. not quite, because I noticed that some data gets cut off from the plot. Still looking- thanks for the suggestion though.

Sam

[Walter Roberson]

set(gca, 'Xlim', [min(time),max(time)], 'YLim', [min(gage),max(gage)])

[Samuel]

that is exactly what I need. Thanks very much walter!