Cant see the line in my plot

for H=200:100:36000 %For loop created for the Height of the satellite

Gc = 398000.5 %Gravitational Constant times Earth's Mass

Re = 6371 %Radius of Earth

V = sqrt(Gc/(Re+H)) %Formula for calculating the Satellite Speed

hold on %Allows to plot multiple times on the same graph

plot(H, V,'-b') %Plot the Height with respect the Speed

end

ylabel('Orbital Speed (Km/S)'), xlabel('Height (Km)') %Labels on each axis

grid on %Grid added for easier understanding of data

My code works but i dont get the plot line when i run this..

Answer 1

[Ruger28]

Don't use plot if you are trying to plot each H vs V value. Use Scatter

for H=200:100:36000  
    Height(H) = H;
    Gc = 398000.5;                                                           %Gravitational Constant times Earth's Mass
    Re = 6371;                                                               %Radius of Earth
    V = sqrt(Gc/(Re+H));                                                     %Formula for calculating the Satellite Speed
    scatter(H, V);    
    hold on                                                                 %Allows to plot multiple times on the same graph
                                                                            %Plot the Height with respect the Speed
end
ylabel('Orbital Speed (Km/S)'), xlabel('Height (Km)')                       %Labels on each axis
grid on 

A more effifient way, and the better answer is this:

clear all;
figure;
Gc = 398000.5;                                                        
Re = 6371;
cntr = 1;
for H=200:100:36000
    V(cntr) = sqrt(Gc/(Re+H))
    Height(cntr) = H;
    cntr = cntr + 1;
end
plot(Height,V)
ylabel('Orbital Speed (Km/S)');
xlabel('Height (Km)');
grid on;

The problem in your script is that you are plotting a single point, rather than a set of x&y values. Scatter plots a single point better.

The second bit of code is most likely what you are looking for.

[vas mit]

Thank you so much it works! Just started with Matlabs for my Thesis project and it can get tricky a lot.

[darova]

Preallocate arrays!