overall area of intersecting rectangles

Hi all, I have multiple rectangles defined by the rectangle() function, as seen in picture 1. The Hight and Width of the rectangles are variables. The positions of the rectangles are affected by each other, so if if the red rectangle gets bigger, the other rectangles will shift along the x- and y- axes.

I want to calculate the overall Area, so basically as shown in picture 2, the area between the axes and the outermost rectangle boundaries.

Any help is appreciated, thanks!

Answer 1

[Matt J]

If you put the rectangles in the form of a polyshape vector, poly, then it is quite easy:

Area= area(union(poly));

[Tobias Eißler]

So you mean, building 1 polyshape vector from outermost points of the rectangles (from points on the drawn red line)?

[Matt J]

No, a vector of polyshape rectangles. E.g.,

poly(1)=polyshape([0,0; 0 1; 1 1 ; 1 0 ]);  %first rectangle

poly(2)=polyshape([0.5,0.5; 0.5 2; 2 2 ; 2 0.5 ]); %second rectangle

plot(poly)

Area  = area(union(poly))

Area = 3

[Tobias Eißler]

I didn't know it was possible like that, thanks a lot!

[Tobias Eißler]

Do you know if there is a simple replacement for polyshape ? MATLAB R2016b doesnt have the function

[Matt J]

No, not unless you can find something on the File Exchange. You can't upgrade?

[Tobias Eißler]

sadly not, it is not my personal version but the one at the institute im working at.

but thanks again for your help! much appreciated!

[Matt J]

Ask them to upgrade...