Scatter plot of data based on speed and load

Hi,

I am new to Matlab and was wondering if I can plot something like this.

I have a 275x3 matrix and particular speed and load points for an engine that form a 275x2 matrix

I want the speed and torque/fueling to form the x and y axis while I have the 275x3 matrix as smooth scatter line fed columnwise.

The output should be 3 lines that form a contour over the speed and load curve for the engine.

The input is like this:

Speed torque/fueling

700 9

700 13

700 17

700 20

700 25

700 30

700 40

700 60

750 9

750 13

750 17

750 20

750 25

750 30

750 35

800 9

800 13

800 17

800 20

800 25

800 30

800 40

800 60

800 90

800 125

800 145

850 9

850 13

850 17

850 20

850 25

850 30

850 35

900 9

900 13

900 17

900 20

900 25

900 30

900 40

900 60

900 90

900 125

900 150

950 9

950 13

950 17

950 20

950 25

950 30

950 35

950 60

950 90

950 125

950 150

950 175

1000 9

1000 13

1000 17

1000 20

1000 25

1000 30

1000 40

1000 60

1000 90

1000 125

1000 150

1000 175

1000 198

1050 9

1050 13

1050 25

1050 30

1050 35

1050 60

1050 90

1050 125

1050 150

1050 175

1100 9

1100 13

1100 17

1100 20

1100 25

1100 30

1100 40

1100 60

1100 90

1100 125

1100 150

1100 175

1100 205

1150 9

1150 13

1150 17

1150 20

1150 25

1150 30

1150 35

1200 9

1200 13

1200 17

1200 20

1200 25

1200 30

1200 40

1200 60

1200 90

1200 125

1200 150

1200 175

1200 215

1250 9

1250 13

1250 17

1250 20

1250 25

1250 30

1250 35

1300 9

1300 13

1300 17

1300 20

1300 25

1300 30

1300 40

1300 60

1300 90

1300 125

1300 150

1300 175

1300 215

1350 9

1350 13

1350 17

1350 20

1350 25

1350 30

1350 35

1400 9

1400 13

1400 17

1400 20

1400 25

1400 30

1400 40

1400 60

1400 90

1400 125

1400 150

1400 175

1400 215

1450 9

1450 13

1450 17

1450 20

1450 25

1450 30

1450 35

1500 9

1500 13

1500 17

1500 20

1500 25

1500 30

1500 40

1500 60

1500 90

1500 125

1500 150

1500 175

1500 215

1550 20

1550 25

1550 30

1550 35

1600 20

1600 25

1600 30

1600 40

1600 60

1600 90

1600 125

1600 150

1600 175

1600 215

1650 20

1650 25

1650 30

1650 35

1700 20

1700 25

1700 30

1700 40

1700 60

1700 90

1700 125

1700 150

1700 175

1700 215

1750 20

1750 25

1750 30

1750 35

1800 20

1800 25

1800 30

1800 40

1800 60

1800 90

1800 125

1800 150

1800 175

1800 215

1850 20

1850 25

1850 30

1850 35

1900 25

1900 30

1900 40

1900 60

1900 90

1900 125

1900 150

1900 175

1900 205

1950 25

1950 30

1950 35

2000 25

2000 30

2000 40

2000 60

2000 90

2000 125

2000 150

2000 175

2000 195

2050 25

2050 30

2050 35

2100 25

2100 30

2100 40

2100 60

2100 90

2100 125

2100 150

2100 175

2100 190

2150 25

2150 30

2150 35

2200 30

2200 40

2200 60

2200 90

2200 125

2200 150

2200 173

2200 177

2230 170

2250 30

2250 35

2300 30

2300 40

2300 60

2300 90

2300 125

2300 150

2350 30

2350 35

2400 30

2400 40

Answer 1

[KSSV]

Read about Scatter, griddata, scatteredinterpolant ..to plot a contour straight away from scattered data, you can use the below function:

https://in.mathworks.com/matlabcentral/fileexchange/38858-contour-plot-for-scattered-data

It seems your data is structured...you can reshape it to a grid and use contour. If you want more help...attach your data as a text file.

[Sridutt Gokul]

Here is the data I am working with, I want Cyl1_m1, Cyl1_m9, Cyl1_m11 as lines over graph where the axes are decided by the first two columns.

Thank you.

[KSSV]

A = importdata('Matlab_forum_question.txt') ;
data = A.data ;

x = data(:,1) ;   % speed 
y = data(:,2) ;   % torque 
z = data(:,3) ;    % cyl1

m = 100 ; n = 100 ;
xi = linspace(min(x),max(x),m) ;
yi = linspace(min(y),max(y),n) ;

[X,Y] = meshgrid(xi,yi) ;
Z = griddata(x,y,z,X,Y) ;

contour(X,Y,Z)

[Sridutt Gokul]

I'm sorry, my requirements have changed.

I want to do a scatter of columns 3 to 5 with correspondence to engine speed being points on the x axis and torque being points on the y axis.

So I can tell if column one is more towards a certain speed/torque area.

[KSSV]

Read the respective columns and use Scatter

A = importdata('data.txt') ;
data = A.data ;
x = data(:,1) ;   % speed 
y = data(:,2) ;   % torque 
c1 = data(:,3) ;    % cyl1
c2 = data(:,4) ;    % cyl2
c3 = data(:,5) ;    % cyl3


figure
hold on

scatter3(x,y,c1,20,'r','filled')
scatter3(x,y,c2,20,'b','filled')
scatter3(x,y,c3,20,'g','filled')

legend({'cyl1','cyl2','cyl3'})