[Talk-GB] GPS vs Potlatch

Dave osm.list at randomjunk.co.uk
Wed Jul 18 17:19:30 BST 2007


On 18/07/07, Thom Shannon <thom at glow-internet.com> wrote:
>
>
> Apologies if this has come up before. But what are the arguments/reasons for
> using the aerial photography or making GPS traces. Is the accuracy of either
> much of a problem? Or is it just that the photos aren't so high-res in
> certain areas, or outdated, so GPS is better.
>

For GPS:
 - GPS was around first before we were allowed to use Yahoo.
 - Yahoo does not cover everywhere, as you say
 - GPS is a record of where you went (useful for linking photos to places etc)
 - GPS lets you map things not immediately obvious from Yahoo, ie:
foot paths in the country side

For Yahoo:
 - GPS is sometimes not very accurate (ie: built up areas) - here it's
easier to trace
 - you don't have to go down *every* road -- you just get the name and
map the extent by tracing -- you have to be careful not to miss foot
paths and side roads though
 - it's easier to put in area features such as park/lake boundaries from Yahoo.
 - you can even get some things like building outlines (for hospitals,
stations prisons etc)
 - you can map some things in places you can't actually go.. mostly
this isn't very useful, but it makes the map look pretty :-)

I mostly use Yahoo, but I always carry a GPS collecting a track log
anyway. That way you get the best of both.

Dave




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