I got the same results with only 26 points as with all 15,000 so I guess the number of points doesn't seem to matter. Something seems to be off a little in MI Pro as to how it creates the voronoi polygons.
-Bob Peter Horsbøll Møller <[EMAIL PROTECTED]> on Thursday, January 12, 2006 at 9:17 AM -0700 wrote: >Have you tried to create voronoi on just those two stores and approx. 30 >stores around these ? >This should give them same result as when you create for all your 58000 >stores > > >Peter Horsbøll Møller >GIS Developer, MTM >Geographical Information & IT > >COWI A/S >Odensevej 95 >DK-5260 Odense S. >Denmark > >Tel +45 6311 4900 >Direct +45 6311 4908 >Mob +45 5156 1045 >Fax +45 6311 4949 >E-mail [ mailto:[EMAIL PROTECTED] [EMAIL PROTECTED] >[ http://www.cowi.dk/gis ]http://www.cowi.dk/gis > > > > > >---------------------------------------------------------------------------From: >Robert DeRubeis [mailto:[EMAIL PROTECTED] >Sent: Thursday, January 12, 2006 4:41 PM >To: [email protected] >Cc: Peter Horsbøll Møller >Subject: Re: [MI-L] voronoi polgon > > >I have used the Distance Calculator in MI Pro v7.8 and that gave the >correct closest store location. But I'm wanting to assign some 58,000 >customers to the closest store. The number of customers will vary >depending on how many customers fall within that particular voronoi >polygon, which is anywhere from zero and up. > >The whole problem seems to be the voronoi for each store is not >representing an area closest to that store for some reason. I'm creating >voronoi polygons from over 15,000 points. Could that be the cause of the >problem? Has anyone else had any similar problems? > >Thanks, >Bob > >Peter Horsbøll Møller <[ mailto:[EMAIL PROTECTED] [EMAIL PROTECTED]> on >Wednesday, >January 11, 2006 at 2:22 PM -0700 wrote: >Bob, > >That sounds kind of strange. The voronoi for each store should represent >the area closer to each store than to any other store - just as you >expect. >And therefore each customer should be within that voronoi that also >contains the store they are closest to. > >Have you tried using the DistanceCalculator, that came with MapInfo 7.8 - >or even the improved one for MapInfo 8.0 ? This tool will give you the >nearest x stores for each customer. x can be 1, 2 or as many as like. So >this would be another way of getting the result, you are looking for. > >The tool from MapInfo 8.0 the result will be represented as a line >between the customer and the store. I'm not sure if this also is the case >with the 7.8 tool > >Peter Horsbøll Møller >GIS Developer, MTM >Geographical Information & IT > >COWI A/S >Odensevej 95 >DK-5260 Odense S. >Denmark > >Tel +45 6311 4900 >Direct +45 6311 4908 >Mob +45 5156 1045 >Fax +45 6311 4949 >E-mail [ mailto:[EMAIL PROTECTED] [EMAIL PROTECTED] >[ http://www.cowi.dk/gis ]http://www.cowi.dk/gis > >-----Original Message----- >From: [ mailto:[EMAIL PROTECTED] >[EMAIL PROTECTED] [[ >mailto:[EMAIL PROTECTED] >]mailto:[EMAIL PROTECTED] On Behalf Of Robert >DeRubeis >Sent: Wednesday, January 11, 2006 5:58 PM >To: [ mailto:[email protected] >[EMAIL PROTECTED] >Subject: [MI-L] voronoi polgon > >List, > >I have 2 point tables, stores and customers. I would like to find all >the customers that are the closest distance to a particular store so I >can assign information from the store to those customers. I created a >voronoi polygon from the store points, then did a select statement where >customer points are within store voronoi polygon. > >My problem is that I noticed in certain cases that some customer points >fell into a store voronoi polygon, but was actually closer to another >store. I measured the distance in MI Pro Ver 7.8 and it was not a big >difference (8.19 instead of 7.78 miles), but wondered why the inaccuracy? > >Thanks, >Bob _______________________________________________ MapInfo-L mailing list [email protected] http://www.directionsmag.com/mailman/listinfo/mapinfo-l
