How can I connect two points on the world map with an arrow pointing at one end?

To calarify, I am trying to create a graph projected on the world map. Therefore my secondary objective is to show the direction of the flows using arrows for each edge.

The code:

I am plotting the world map using:

figure;
worldmap('World')
load coastlines %#ok<LOAD>
plotm(coastlat,coastlon)

Next, I am adding the two points using scatterm:

ln = [30 -30]; % longitudes of points 
lt = [0 0]; % latitudes
scatterm(ln,lt,'filled','red')

Finally, connecting the points with a geodesic line (great circle):

[l,g] = gcwaypts(ln(1),lt(1),ln(2),lt(2),20);
geoshow(l,g,'displaytype','line','color',[.5 0 .5],...
                          'markeredgecolor','r','marker','none');

Answer 1

[darova]

I'd draw it manually if the line is vertical or horizontal:

x = [2 2];
y = [0 -4];        % line
plot(x,y)
hold on
plot([0  1]+x(2),[0 1]+y(2))
plot([0 -1]+x(2),[0 1]+y(2))
hold off

[Alexandros Tzimas]

Thanks for your answer, however, your answer just connects two points on a 2D cartesian space. My question was about the geographical space (using longitude and latitude) since I am working on a world map as mentioned above. Furthermore, the line should be of great circle and not just a linear one. Also, my question was about an arrow connecting the two points on the map to show the flow. Therefore the answer is wrong.

[darova]

I'm sorry :(

[Alexandros Tzimas]

It's ok, thanks for your time.