[OSM-newbies] Data precedence: Yahoo or GPS?

[Andy Robinson (blackadder-lists)]

Dave Stubbs
>Sent: 23 June 2008 12:22 PM
>To: newbies at openstreetmap.org
>Subject: Re: [OSM-newbies] Data precedence: Yahoo or GPS?
>
>On Mon, Jun 23, 2008 at 12:00 PM, Victor Snesarev
><victor.snesarev at gmail.com> wrote:
>> I am starting to use a GPS to map trails (highway=footway) around town.
>Some
>> of the trails or sections of a trail are also visible in the Yahoo
>imagery.
>> When there are disagreements between my GPS track and Yahoo imagery,
>which
>> one should take precedence? I am guessing Yahoo, but want to confirm this
>> with the community.
>>
>> For an example see this footpath in Edit mode:
>>
>> http://www.openstreetmap.org/?lat=35.75856&lon=-
>78.78667&zoom=17&layers=0B0FT
>>
>
>
>That depends. Sometimes the Yahoo imagery can be offset a bit, in
>which case you trust your GPS. Also the imagery is often not exactly
>top-down, some places this is more obvious than others -- this means
>that hills can make straight roads look curved when they're just
>humped.
>But in this case the imagery seems to be in the right place, and your
>GPS trace went under some trees... so I'd probably trust the Yahoo
>more.
>


I agree with Dave on this one, although IO tend to average between the two
source where it applies. Over time you and others might get more GPS traces
for the same route and then you can move the emphasis over to the GPS and
ignore the Y!

Cheers

Andy