Plot data vs time color coded by ID

Hi,

MATLAB newbie here. I'm trying to plot the range in miles of two aircraft from where I am over time on the same plot.

Here is an example of the data from a table named 'data':

'15:02:03' 1 24.492

'15:02:03' 2 25.653

'15:02:04' 1 24.489

'15:02:04' 2 25.650

'15:02:05' 1 24.485

'15:02:05' 2 25.646

'15:02:06' 1 24.482

'15:02:06' 2 25.643

'15:02:07' 1 24.478

'15:02:07' 2 25.639

---------------------------

The variables I'm using are:

Column 1 is data.time

Column 2 is data.ID

Column 3 data.range

I'm able to plot time vs. range using plot(data.time, data.range), but what I need to do is plot each aircraft's range vs. time color coded by data.ID and I thought it would be simpler than it is, but I'm a stumped. I'm pretty sure I need a for loop to loop through data.ID in data but can't figure out the syntax. Thanks for any help!

JB

[Image Analyst]

Is data.time string or character variables? Or time series variable? Or doubles? It's easiest if they're numerical not strings. Please attach your table in a .mat file with the paperclip icon so we can begin on helping you.

save('answers.mat', 'data')

[Jen B]

Hi,

I wasn't sure how to attach the file before and it looks like there are a couple of other answers as well but I've attached it anyway. Thanks for the help!

Answer 1

[William Rose]

@Jen B,

I have copied your data into a text file and have attached it.

I notice there are two planes and a distance to each one at each time. The times are strings.

Let's figure out how many planes rhere are, so the code will generalize for a future input data file in which there are 3 or more plane distances at every time. Then lop through th code to make a vector of times and a distance array with time along the rows and a different plane in each column.

Then we will plot time vs dist1 and time vs dist2, with different colors.

T=readtable('jbdata.txt');          %T has strings and numbers
nPlanes=max(T.Var2);                %number of planes
nTimes=length(T.Var2)/nPlanes;      %number of times
A=zeros(nTimes,nPlanes);            %allocate array
for i=1:nTimes
    t(i)=T.Var1((i-1)*nPlanes+1);
    for j=1:nPlanes 
        A(i,j)=T.Var3((i-1)*nPlanes+j);  %distance
    end
end
%If there are more than 2 planes, make next line a for loop over planes
plot(t,A(:,1),'rx',t,A(:,2),'bx');  %plot time vs distance for each plane
legend('Plane 1','Plane 2');        %adjust if >2 planes
xlabel('Time'); ylabel('Distance'); grid on

Try it.

[Jen B]

Thank you!

[William Rose]

You're welcome @Jen B

Answer 2

[Cris LaPierre]

I wonder if gscatter does what you want. There is no line, however.

gscatter(x,y,g)

time = ['15:02:03';	'15:02:03';	'15:02:04';	'15:02:04';	'15:02:05';	'15:02:05';	'15:02:06';	'15:02:06';	'15:02:07';	'15:02:07'];
ID = [1	2	1	2	1	2	1	2	1	2]';
range = [24.492	25.653	24.489	25.65	24.485	25.646	24.482	25.643	24.478	25.639]';
data = table(time,ID,range);

% convert times to duration
data.time = duration(string(data.time),"InputFormat","hh:mm:ss")

data = 10×3 table
      time      ID    range 
    ________    __    ______

    15:02:03    1     24.492
    15:02:03    2     25.653
    15:02:04    1     24.489
    15:02:04    2      25.65
    15:02:05    1     24.485
    15:02:05    2     25.646
    15:02:06    1     24.482
    15:02:06    2     25.643
    15:02:07    1     24.478
    15:02:07    2     25.639

gscatter(data.time, data.range,data.ID)

If you want a line, perhaps unstack can be used to get you closer to what you want.

idData = unstack(data,"range","ID")

Warning: Table variable names that were not valid MATLAB identifiers have been modified. Since table variable names must be unique, any table variable names that happened to match the new identifiers also have been modified.
To use the original INDVAR values as table variable names, set 'VariableNamingRule' to 'preserve'.

idData = 5×3 table
      time        x1        x2  
    ________    ______    ______

    15:02:03    24.492    25.653
    15:02:04    24.489     25.65
    15:02:05    24.485    25.646
    15:02:06    24.482    25.643
    15:02:07    24.478    25.639

plot(idData.time,idData{:,["x1","x2"]})
legend

[Jen B]

Thank you so much!