Memory Map Question
 

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[Closed] Memory Map Question

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 IHN
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I have 1:50k and 1:25k maps of the same area, but they don't quite 'line-up' - i.e. if I draw a route along a, say, bridleway on the 1:25k and the scale out to the 1:50k, the route's no longer on the bridleway its slightly off to one side. Same if I do it the other way round.

Any ideas? I assume it's something to do with the datum in the maps.


 
Posted : 27/02/2009 12:06 pm
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It's possible to get a shift if you use the wrong geodetic system, but both the 1:50 and 1:25 map should use the same if they are both OS:

http://en.wikipedia.org/wiki/OSGB36


 
Posted : 27/02/2009 12:31 pm
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Common problem. You can see the same if you draw a route along a 1:50k map and then "zoom out" to 1:250k on Anquet


 
Posted : 27/02/2009 12:32 pm
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PIA that. Shouldn't happen but does, all the time. All maps, at whatever scale are supposed to be drawn from the same database


 
Posted : 27/02/2009 12:56 pm
Posts: 3706
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Same thing happens on TrackLogs. Pretty sure it's down to the OS data, not the software.

I've got a route for Stanage Edge that runs parallel to the path on the ground. Following the GPS route precisely would have me over the edge for much of the way.


 
Posted : 27/02/2009 1:02 pm