does two polygons interest or not?

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CHANDRABHAN Singh
回答： Steven Lord 2022-1-6
Let's say
these are two non interscting ploygons (shown below). How can i get a logical relationship out of this. Something like, if the polygons intersect or touch
paramter = true;
otherwise
parameter = false;
x1 =[-2.6967 -2.0891 -0.0846 1.5544 2.6872 -2.6967];
x2 = [5.6494 6.6386 6.6898 4.0313 1.3002 1.9802 5.6494];
y1 = [ 0.1340 -1.7104 -2.6987 -2.2076 -0.2624 0.1340];
y2 = [1.8624 3.4274 4.2346 6.6998 3.9686 2.2082 1.8624];
plot(x1,y1,x2,y2);
grid on;
poly1 = polyshape(x1',y1');
poly2 = polyshape(x2',y2');
polyout = intersect(poly1,poly2);

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采纳的回答

Steven Lord
Steven Lord 2022-1-6
You may be able to use the approach from this blog post that determines if two states (represented as polyshape objects) share a border.

更多回答（1 个）

DGM
DGM 2022-1-6
编辑：DGM 2022-1-6
Ran in:
You could test for an overlap using the intersection you calculated:
x1 = [0 1 1 0 0];
y1 = [0 0 1 1 0];
x2 = [1 2 2 1 1]-0.2;
y2 = [1 1 2 2 1]-0.2;
plot(x1,y1,x2,y2);
grid on;
poly1 = polyshape(x1',y1');
poly2 = polyshape(x2',y2');
polyout = intersect(poly1,poly2);
theyintersect = polyout.NumRegions~=0 % returns a logical scalar
theyintersect = logical
1
Although that won't return true if they are merely tangent.
x1 = [0 1 1 0 0];
y1 = [0 0 1 1 0];
x2 = [1 2 2 1 1];
y2 = [1 1 2 2 1]-0.2;
plot(x1,y1,x2,y2);
grid on;
poly1 = polyshape(x1',y1');
poly2 = polyshape(x2',y2');
polyout = intersect(poly1,poly2);
theyintersect = polyout.NumRegions~=0
theyintersect = logical
0
  2 个评论
CHANDRABHAN Singh
CHANDRABHAN Singh 2022-1-6
编辑：CHANDRABHAN Singh 2022-1-6
@DGM can you please give me some idea what exactly is "polyout.NumRegions"? And thank you for your kind supoort.
DGM
DGM 2022-1-6
编辑：DGM 2022-1-6
From the webdocs:
https://www.mathworks.com/help/matlab/ref/polyshape.html
The NumRegions property is described as:
Number of regions making up the polygon, specified as a scalar integer. A region is an area bounded by an outer boundary, which may contain hole boundaries that lie entirely inside the outer boundary.
So a simple polyshape (e.g. a square) would have one region. If a polyshape intersects itself (e.g. a bowtie), it might have more than one region. If a polyshape encloses zero area, it has zero regions.
As a trivial polyshape has zero vertices, you could alternatively check to see if the vertex list is empty.
theyintersect = numel(poly1.Vertices)~=0
I just chose to use NumRegions instead.

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