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Below is the code that we need to modify in order to get all the desired output variables for each curved-edge polygon/arc-polygon (i.e., vertex numbers/coordinates for each arc-polygon, number of edges for each arc-polygon, total perimeter length for each arc-polygon, area of each arc-polygon, or in other words, areas_by_algebra for each arc-polygon), and store all of these outputs in columns within a single file for future analysis:

% close all figures and clear all variables

close all;

clearvars;

% load data

load('fpep.mat');

% create the object

obj=TripletGraph2(fpep);

% draw the figure

% obj.plotspline;

obj.plotcirc;

% hold the figure and draw upon the previous figure

axis equal;

hold on;

% get polygons from the object

[polygons, vertices_index] = getPolyshapes(obj);

% get the arc point information

arcpoint = obj.ArcPoints;

% interpolation length

sq=linspace(0,1,100)-0.5;

% for each polygon, calculate its area and draw it

for i= 1:1:length(polygons)

% get the vertices of current polygon

vertices = polygons(i).Vertices;

% calculate its approximation area

area(i) = polyarea(vertices (:,1), vertices (:,2));

% plot the current polygon

plot(polygons(i));

axis equal;

hold on;

% for each edge of this polygon, build the circular segment from the arc

for edge = 1:1:size(vertices,1)

% use start and end points C1, C2 of this edge as a key, find the two

% bridge points V1 V2 between them

start_point = vertices(edge, :);

if edge + 1 > size(vertices,1)

end_point = vertices(mod(edge+1, size(vertices,1)), :);

else

end_point = vertices(edge+1, :);

end

temp = arcpoint(:,:,sum(arcpoint(:,1,:)==start_point')==2);

res = temp(:,:,sum(end_point'==temp(:,4,:))==2);

if isempty(res)

temp = arcpoint(:,:,sum(arcpoint(:,1,:)==end_point')==2);

res = temp(:,:,sum(start_point'==temp(:,4,:))==2);

end

if isempty(res)

error('can not find V1 and V2!!')

end

% C1 start point, C2 end point, V1 V2 bridge points

C1 = res(:,1,:);

C2 = res(:,4,:);

V1 = res(:,2,:);

V2 = res(:,3,:);

% calcuate by polyarea

L=norm(C2-C1);

U=(C2-C1)/L;

dV1=(V1-C1)/norm(V1-C1);

dV2=(V2-C2)/norm(V2-C2);

theta1=acosd(dot( dV1, U) );

theta2=acosd(dot( dV2, -U) );

theta=(theta1+theta2)/2;

arcradius=norm(C1-C2)/(2*sind(theta));

W=cross( cross([U;0],[dV1;0]), [U;0]);

W=W(1:2)/norm(W);

D=L/2;

t=2*D*sq;

Dcot=D*cotd(theta);

s=sqrt(Dcot.^2-(t.^2-D.^2))-Dcot;

XY=(C1+C2)/2+U*t+W(1:2)*s;

X = XY(1,:);

Y = XY(2,:);

% estimate arc segment as polygon

circle_segement = polyshape(X, Y);

plot(circle_segement);

area_by_polygon = polyarea(X, Y);

% end here

% calculate arc segment w/ algebra

ca = 2* theta;

r = arcradius;

circle = pi * r ^ 2;

triangle = r ^ 2 * sind(ca) / 2;

area_by_algebra = circle * ca / 360 - triangle;

% algebra ends here

% if V1 V2 live inside the polygonal area, we should substract the circle_segement

if inpolygon([V1(1),V2(1)], [V1(2),V2(2)], vertices (:,1), vertices (:,2))

area(i) = area(i) - area_by_algebra;

% if V1 V2 live outside the polygonal area, we should add the circle_segement

else

area(i) = area(i) + area_by_algebra;

end

end

end

% display the area values

disp(area);

Thanks in advance for your help!

Pravin Jagtap
on 23 Dec 2019

Edited: Pravin Jagtap
on 23 Dec 2019

Hello Steve,

The objective mentioned in the question can be easily achieved by using the ‘save’ command. Refer following example for saving the variables the variables

p = rand(1,10); % column vector

q = rand(1,10); % column vector

% make sure that the variable you want save are in require format

data = [p' q'] % collect the variables you want to save in one matrix

save('pqfile.mat','data') % 'pqfile.mat' file will get created in the same directory

% load it for further analysis

For more details, refer following documentation

~Pravin

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