Contour plot in 2D using x,y,z data

I have x,y,z datalike this the attached text file. I would like to make a contour plot using this data. I am using the code

Sublat = Summer2015(:,2);

Sublong = Summer2015(:,1);

TECDev = Summer2015(:,3);

contourf(Sublong,Sublat,TECDev);

But there is an error.

Can you please help?

[Sargondjani]

Please be more specific about your error

Answer 1

[Star Strider]

Try this —

Summer2015 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/791769/Summer2015.txt', 'VariableNamingRule','preserve')

Summer2015 = 2212×3 table
     Var1      Var2       Var3  
    ______    ______    ________

    86.442     31.05    0.071639
    86.434    31.009    0.075361
    86.427    30.968    0.079066
    86.418    30.931     0.07982
     86.41    30.894    0.077607
    86.403    30.854    0.073443
    86.396    30.814    0.070311
    86.388    30.778     0.06718
    86.379    30.739    0.064148
    86.374      30.7    0.056197
    86.365    30.661    0.052311
    86.357    30.621    0.052557
    86.349    30.586    0.050918
    86.343    30.548    0.044311
    86.335     30.51     0.03682
    86.329    30.472    0.029475

Sublat = Summer2015{:,2};
Sublong = Summer2015{:,1};
TECDev = Summer2015{:,3};

latv = linspace(min(Sublat), max(Sublat), height(Summer2015));
lonv = linspace(min(Sublong), max(Sublong), height(Summer2015));
[Lam,Lom] = ndgrid(latv,lonv);
TECDevm = griddata(Sublat, Sublong, TECDev, Lam, Lom);

figure
contourf(Lam, Lom, TECDevm)
axis('equal')

There may be Mapping Toolbox functions for this that could be more appropriate. Nevertheless, this illustrates how to create the matrices that contourf wants.

.