[Tagging] simple_brunnel : one node bridge like xing highway over waterway

Dave F. davefox at madasafish.com
Thu Apr 3 17:08:46 UTC 2014


On 02/04/2014 17:14, Richard Z. wrote:
> as explained in the rationale the dimensions of the bridge/culvert are 
> frequently only a fraction of the achievable precision. Think of a 
> track crossing a small creek in a forest valley int the mountains. The 
> GPS precision will be 10 meters if you are lucky, the brunnel 2-3m. 
> Mapping this the old fashioned way will produce junk data, not precision.

Rubbish. Please don't rely on a GPSr. It is only one, of many, ways to 
survey. If I see a small bridge over a stream, say 3m I'll map is as 
that, because that's how it accurately is in the real world. Some users 
have access to detailed aerial imagery to help map accurately.

David Fox

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