Jorge,
Your problem is very similar to one I just solved myself thanks to the help on this forum.
See https://www.mathworks.com/matlabcentral/answers/583166-extract-data-points-within-a-closed-boundary
In the code below, Blat is a vector of border latitudes and Blon is a vector of border longitudes. For your example, Blat would be a 1x5 vector containing the latitudes of your 5 points. In my code below, the matrix prom_world contains a large set of points with latitudes in column 1 and longitude in column 2.
The Matlab function inpolygon determines what elements of prom_world lie within or on the polygon defined by Blat and Blon. A logical 1 is returned if the point is in or on the boundary and a logical 0 is returned if the point is outside the boundary.
If you want to extract a matrix of point that are in or on the boundary, compute the vector of indicies of INON which are non-zero and then use that info to pull the data out as shown.
The Matlab help for inpolygon probably explains this better than I have.
% Find points IN or ON the boundary
[IN ON] = inpolygon(prom_world(:,1),prom_world(:,2),Blat,Blon);
%
% Combine IN and ON
INON = IN | ON;
%
% Find indicies of non-zero INON
idx = find(INON(:));
%
% Extract data from prom_world
Prominence = prom_world(idx,:);
