How to get the intersection points ??

Hi all, I have the following code to get the intersection points between these multiple lines and these multiple circles.
%%center of circles
X = [0.02 0.44; 0.08 0.58 ;...
0.22 0.57; 0.3 0.9; ...
0.44 0.79; 0.35 0.318;...
0.54 0.29; 0.95 0.11;...
0.93 0.7; 0.82 0.93];
C_M=[X(:,1) X(:,2)];
hold on
%%Assign labels to the points.
Assign_labels_to_all_points ( X ,X(:,1),X(:,2))
hold on
%%Draw circles
theta = linspace(0,2*pi) ;
x = 0.15*cos(theta) ; y =0.15*sin(theta) ;
C_M=[X(:,1),X(:,2)];
deg = 0 : 2.5 : 90;
for i=1:length(deg)
r =2;
x_ax = r*[zeros(size(deg(i))) cosd(deg(i))];
y_ax = r*[zeros(size(deg(i))) sind(deg(i))];
%%plot lines with different angles
plot(x_ax, y_ax, 'LineWidth',1.3)
for index = 1:length(C_M)
if ~isinf(C_M(index))
xx = x+C_M(index,1);
yy = y+C_M(index,2);
%%plot circles
plot(xx,yy,'-b','linewidth',1.5)
for j=1:length(deg)
P = InterX([x+C_M(index,1);y+C_M(index,2)],[r*[zeros(size(deg(j))) cosd(deg(j))];r*
[zeros(size(deg(j))) sind(deg(j))]]);
%%plot intersection points between lines and circles
plot(P(1,:),P(2,:),'or');
end
end
end
end
%%x and y axis limits
xlim([-0.2,1.2])
ylim([-0.2,1.2])
grid on
grid minor
I used the file exchange function InterX. It only draws the intersection points as the following image. But, I can't get these intersection points to store them in matrix or array.
So, my question is: How to get the intersection points between each line and the circles that intersected with that line and store them in array or matrix?? Any suggestions to modify this code??

1 件のコメント

Image Analyst
Image Analyst 2020 年 2 月 1 日
Original question (in case he delete this one also):
How to get the intersection points between (each line and the circles that intersected with that line)??
Hi all, I have the following code to get the intersection points between these multiple lines and these multiple circles.
%%center of circles
X = [0.02 0.44; 0.08 0.58 ;...
0.22 0.57; 0.3 0.9; ...
0.44 0.79; 0.35 0.318;...
0.54 0.29; 0.95 0.11;...
0.93 0.7; 0.82 0.93];
C_M=[X(:,1) X(:,2)];
hold on
%%Assign labels to the points.
Assign_labels_to_all_points ( X ,X(:,1),X(:,2))
hold on
%%Draw circles
theta = linspace(0,2*pi) ;
x = 0.15*cos(theta) ; y =0.15*sin(theta) ;
C_M=[X(:,1),X(:,2)];
deg = 0 : 2.5 : 90;
for i=1:length(deg)
r =2;
x_ax = r*[zeros(size(deg(i))) cosd(deg(i))];
y_ax = r*[zeros(size(deg(i))) sind(deg(i))];
%%plot lines with different angles
plot(x_ax, y_ax, 'LineWidth',1.3)
for index = 1:length(C_M)
if ~isinf(C_M(index))
xx = x+C_M(index,1);
yy = y+C_M(index,2);
%%plot circles
plot(xx,yy,'-b','linewidth',1.5)
for j=1:length(deg)
P = InterX([x+C_M(index,1);y+C_M(index,2)],[r*[zeros(size(deg(j))) cosd(deg(j))];r*
[zeros(size(deg(j))) sind(deg(j))]]);
%%plot intersection points between lines and circles
plot(P(1,:),P(2,:),'or');
end
end
end
end
%%x and y axis limits
xlim([-0.2,1.2])
ylim([-0.2,1.2])
grid on
grid minor
I used the file exchange function InterX. It only draws the intersection points as the following image. But, I can't get these intersection points to store them in matrix or array.
So, my question is: How to get the intersection points between each line and the circles that intersected with that line and store them in array or matrix?? Any suggestions to modify this code??

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 採用された回答

Matt J
Matt J 2018 年 8 月 17 日
編集済み: Matt J 2018 年 8 月 17 日

1 投票

Can't you just modify as follows,
P{i,j} = InterX([x+C_M(index,1);y+C_M(index,2)],[r*[zeros(size(deg(j))) cosd(deg(j))];r*
[zeros(size(deg(j))) sind(deg(j))]]);
%%plot intersection points between lines and circles
plot(P{i,j}(1,:),P{i,j}(2,:),'or');

6 件のコメント

Eman S
Eman S 2018 年 8 月 18 日
編集済み: Eman S 2018 年 8 月 18 日
@Matt J
Thanks so much for your answer. When I use your code, it gives me the output like that;
P =
Columns 1 through 2
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x2 double] [2x2 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
Columns 3 through 4
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x2 double] [2x2 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
Columns 5 through 6
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x2 double] [2x2 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
Columns 7 through 8
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x2 double] [2x2 double]
[2x2 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
Columns 9 through 10
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x2 double] [2x2 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
[2x0 double] [2x0 double]
To get the values, I must write like that; P{8,1}.
>> P{8,1}
ans =
0.84813 1.052
0 0
Is there any method to get the values instead of [2x0 double]??
Matt J
Matt J 2018 年 8 月 18 日
The 2x0 contents are the values. I assume this means that no intersection was detected.
Eman S
Eman S 2018 年 8 月 18 日
編集済み: Eman S 2018 年 8 月 18 日
Yes, the 2x0 contents are the values and they are empty. But, the 2x2 contents have values, like;
P{8,1}= 0.84813 1.052
0 0
So, how to remove the 2X0 elements and get the values of 2x2 elements??
Matt J
Matt J 2018 年 8 月 18 日
P(cellfun('isempty',P))=[];
But if you get rid of them, how will you know which circle/line pair a 2x2 value corresponds to?
Matt J
Matt J 2018 年 8 月 18 日
This will give you a map of where the non-empty P{i,j} lie
map=~cellfun('isempty',P)
Eman S
Eman S 2018 年 8 月 18 日
編集済み: Eman S 2018 年 8 月 18 日
Thanks so much for your reply and your help.

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