Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!bloom-beacon!eru!luth!sunic!nuug!ulrik!ulrik!tevfik From: tevfik@ulrik.uio.no (Tevfik Karagulle) Newsgroups: comp.graphics Subject: Re: AREA MEASUREMENT OUT OF POLYGON-CONTOUR DATA Message-ID: Date: 10 Aug 90 08:11:51 GMT References: Sender: tevfik@ulrik.uio.no (Tevfik Karagulle) Distribution: comp.graphics Organization: Anatomical Institute, University of Oslo, Norway Lines: 31 In-Reply-To: dick@prisma.cv.ruu.nl's message of 9 Aug 90 14:15:55 GMT In article dick@prisma.cv.ruu.nl (Dick Bakker) writes: >> I am looking for a method to calculate the area of a >> contour out of the polygon-data that describes the >> contour. >> e.g. I have 100 points that describe a contour (x,y- >> coordinates) and I'd like to calculate the area of it. >> Does anyone know an algorithm that can do such a thing? From 'Foley, Van Dam : Fundamentals of Interactive Computer Graphics, 1982, p.513' : For instance, the area C of the polygon projected onto xy plane is just n ---- 1 \ C = - \ (y + y ) (x + x) 2 / i i@1 i i@1 / ---- i=1 where the operator @ is normal addition except that n@1 = 1. Regards, Tevfik Karagulle, UiO, Norway (Internet : tevfik%vision01@ifi.uio.no)