Henry Gomersall wrote: >Sent: 06 April 2010 5:39 PM >To: Jason Cunningham >Cc: [email protected] >Subject: Re: [Talk-GB] tracing lakes with Potlatch > >On Tue, 2010-04-06 at 17:26 +0100, Jason Cunningham wrote: >> The detail for water is excellent and may be the most 'detailed' >> vector data OS is going to provide. It's far better than the OSM >> community could achieve with GPSr's and aerial image tracing. > >Do you know how OS do the water detail? I've often wondered how they >manage to get such good detail of really tiny streams in the middle of >nowhere, often obscured by trees.
They do have about 200 years head start ;-) A lot of stuff nowadays is done from aerial imagery, but they can still drop back to traditional surveying methods if required. Cheers Andy > >Looking at the second link, there are islands in the stream that are >marked on the map, but simply not visible on the aerial imagery. I >suspect ground imaging radar would highlight water, but surely this has >similar tree obscuring issues. > >cheers, > >Henry > > >_______________________________________________ >Talk-GB mailing list >[email protected] >http://lists.openstreetmap.org/listinfo/talk-gb > >No virus found in this incoming message. >Checked by AVG - www.avg.com >Version: 9.0.791 / Virus Database: 271.1.1/2793 - Release Date: 04/05/10 >19:32:00 _______________________________________________ Talk-GB mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk-gb
