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ruby-on-railspostgispolygonsrgeo

Find radius from centroid

I'm converting a KML file to a polygon stored on my database thanks to RGeo

I need the centroid: @area.centroid and I would like to find the approximative radius on my shape. I don't know if it's possible. My database field is a geometry. That means I can store polygons AND multi-polygons. The type of my area is RGeo::Geos::CAPIMultiPolygonImpl

Finally I think I need the check if the area is a simple polygon or a multiple. If it's a simple one, I would like to find the radius. Else nothing.

Thank you for your help !

Solution

  • I finally did like below:

    1. Convexe Hull
    2. Centroid of this Convexe Hull
    3. minimum distance between Convexe Hull points (thanks to exterior_ring function) and the centroid

    By the way I don't know why I had to take the minimum. It was to adapt my scale. I don't really understand how the centroid of a polygon (which could have really strange shape) can be found.

    Anyway, it's working thanks to the 3 steps written previously.