polygon

I'm looking for a way to draw a self intersecting polygon with holes, I'm using the HTML Canvas element. So given 5 points, I want to draw the red one below. This question is essentially the same thing. Note: I don't want to do this using line intersections and adding more points, the actual paths I will be using will be curved. You can't draw the first pentagram with a single path in Canvas 2D - the fill rule being used there is even-odd and Canvas fills shapes with the non-zero winding rule. I think you'll need to compute the intersection points for the corners of the interior pentagon and

I have as an input a 2D polygon with holes, and I need to find it's straight skeleton, like in the picture: (source: cgal.org ) Maybe there is a good Java library for it? And if not, can you point me to the good explanation of the algorithm, so I could implement it myself? (I haven't found good resources on Google) I wrote this a little while back. Not sure if it's robust enough. https://github.com/twak/campskeleton (edited for 2018...) See http://www.sable.mcgill.ca/~dbelan2/roofs/roofs.html which contains an applet. Edit: Ah. I see that " Straight Skeleton " is a technical term. The

I found in here this document. I read it but I keep wondering how to define a Polygon with 3 rings in WKT ? You can use either the POLYGON or the MULTIPOLYGON type, but make sure the outer container ring is listed first followed by the inner hole rings. The orientations of the inner rings are not important since holes are explicit in the syntax. X & Y are space separated, coordinates are comma separated, and ring extents are limited by parentheses and separated by commas. Polygons (outer ring plus any inner rings) are also limited by parentheses. Finally, inner rings cannot cross each other,

I'm currently building a 'search an area' feature for a site we're working on. A bit like the one on Rightmove . I've got everything up and running except the ability to track event changes to a polygon (the setting of new points and altering existing ones). I need to be able to post the coordinates to the form for submission. I've tried the Google Code docs for editing events . And every time I try it out, I either get a message about 'set_at' not being possible or my object not being defined. I suppose the bit I know is wrong is thePolygon variable not being passed through to the new google

I extracted country outline data from somewhere and successfully managed to convert it into an array of lat-lng coordinates that I can feed to Google maps API to draw polyline or polygons. The problem is that that there are about 1200+ points in that shape. It renders perfectly in Google maps but I need to reduce the number of points from 1200 to less than 100. I don't need a very smooth outline, i just need to throw away the points that I can live without. Any algorithm or an online tool that can help me reduce the number of points is needed. Unreason I think MapShaper can do this online