MATLAB: Pleas, i seek a programme (.*m) of polygon interior detection (non-convex polygon)

convexdetectionpolygon

hi, please, i seek a programme (.*m) of polygon interior detection (non-convex polygon and non contour polygon)

Best Answer

Is there some reason why inpolygon is unsatisfactory? It is already in MATLAB.

My guess is, you did not know it exists is the reason.

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Use bwconvhull.

MATLAB: Select points inside a polygon

Here is the code using POLYSHAPE

load('Points.mat')
load('polygon1_x.mat')
load('polygon1_y.mat')
lat = Points.lat;                                         % x of points = lat
lon = Points.lon;                                         % y of points = lon
wpixel = 0.5;
hpixel = 0.5;
pixel0 = [-1  1 1 -1;
          -1 -1 1  1]' .* [wpixel, hpixel]/2;
Island = polyshape([polygon1_y(:) polygon1_x(:)]);
for k=1:length(lat)
    poly = polyshape([lon(k) lat(k)]+pixel0);
    Ik = intersect(poly,Island);
    isin = ~isempty(Ik.Vertices);
    pixel(k).poly = poly;
    pixel(k).isin = isin;
end
% Index of pixel that intersect with Island
idxin = find([pixel.isin]) % <=== HERE IS THE INDEX YOU NEED 
% Graphical output
close all
plot(Island)
hold on
for k=1:length(pixel)
    if pixel(k).isin
        color = 'r';
    else
        color = 'w';
    end
    plot(pixel(k).poly, 'FaceColor', color);
end
axis equal

Best Answer

Related Solutions

MATLAB: Merge non-intersecting polygons

MATLAB: Select points inside a polygon

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