polygon

In order to create a VBO in OpenGl, I need to convert polygons to triangles. Is there an example of script/code somewhere that would describe this ? I would need something robust for convex and concave polygons. Ear clipping is by far the best way to do this. It is fully robust for both convex and concave polygons and runs in O(n^2) time Implement Chazelle's method . Triangulation in linear time! What's not to like? :) More realistically, poly2tri . GLU tesselators provide a flexible way to do this. 来源： https://stackoverflow.com/questions/7316000/convert-polygon-to-triangles

I'm new to the mongodb geolocation features. I stored some polygons that represent the country borders in a database along with the country name. Now what i would like to do is checking which country a point is in. For example if i give my own geolocation i would like to get the country where i am. Is there a way to do it with mongodb? Maybe with geoWithin? Thank you You must store your location data like this schema: {"loc": {"coordinates":[ [ [1.0,1.0], [1.0,10.0], [10.0,10.0], [10.0,1.0], [1.0,1.0] ] ], "type":"Polygon" } } and then send $geoIntersects queries db.polygons.find({"loc":{"

I am looking for a javascript library that supports the ability to pass a zipcode or city as a parameter, and get a list of x,y coordinates to draw a polygon using google maps? Does this exist? Does the google maps API support such queries? I am looking for an array of coordinates similar to those that google uses to draw maps on a google query: Google Maps API doesn't support that kind of solution. There are a couple other places from which you can get the coordinates, though: Flickr API There is a Flickr API based on photos that people tag, but it's only as accurate as the people who tag

I have been looking for how to determine coordinates of the points which consist a polygon(feature) in OpenLayers. Let's say I have created a polygon like the one in this example. I need to know the points which consist the polygon, so I can save them somewhere. I bet it is an easy one. I just couldn't find anything, probably I don't know what I should search for. Thanks in advance. Found it finally! vectors.features[0].geometry.getVertices() 来源： https://stackoverflow.com/questions/3836676/how-to-get-coordinates-of-a-polygon-in-openlayers

I've recently encountered a need for a library or set of libraries to handle operations on 2D polygons. I need to be able to perform boolean/clipping operations (difference and union) and triangulation. So far the libraries I've found are poly2tri , CGAL , and GPC . Poly2tri looks good for triangulation but I'm still left with boolean operations, and I'm unsure about its maturity. CGAL and GPC are only free if my own project is free. My particular project isn't commercial, so I'm hesitant to pay or request for any licenses. But I may want to use my code for a future commercial project, so I'm

I have a Google map with drawing manager enabled where a user can draw a polygon and save it to my db. I added an event listener to the drawingManager object for the overlaycomplete event. When the event is fired, the coordinates of the polygon are written to a hidden field. This works great - the only problem being that if the individual vertices are dragged/changed after that point the event isn't fired. I need to either update the field on(any)change or iterate through the polygon vertices when the user hits submit and write them to the hidden field. I can't quite figure out how to get this