Region Monitoring - didEnterRegion

I want to check whether iPhone is in a particular region and the region coordinates I am getting from web.On web region is a polygon, but as CLregion has only one function i.e. initCircularRegion, how can I convert that points of polygon region to get a 开发者_如何学运维circular region for which I can do monitoring, or is there any other method by which I can know whether I am in a particular polygon region?

Method for checking geolocation point in a polygon region can be found at

http://od-eon.com/blogs/tudor/geo-location-point-inside-area/

logic can be converted for objective-c Checked and found it correct