[OSM-dev] Garmin GPX madness

[David Earl]

On 21/09/2008 13:17, Oliver Eichler wrote:
> On Sunday, 21. September 2008 13:41:58 David Earl wrote:
>> On 20/09/2008 22:08, Stefan de Konink wrote:
>>> I sincerely wonder why anyone in the community would buy a Garmin as
>>> tracking device after (s)he is aware that the device doesn't report
>>> h-/v-/p-dop. This is even more basic functionality...
>> I have no idea what "h-/v-/p-dop" means so it would hardly be a reason
>> for me not to buy one! Am I alone in not understanding your acronym?
>>
>> Mine seems to do the job I bought it for, at competitive price. I wish
>> it had one-touch auto-numbered waypoints though.
> 
> It's the horizontal, vertical and positional dilution of a GPS position, due 
> to satellite position. Without that it's hard to judge the quality of a 
> track. See wikipedia on "DOP".
> 
> You can derive this information from the almanach later on, but it would be 
> nice to have it recorded, too. Next to other information like velocity and 
> heading. 

OK, I understand now. But I still don't know what I'd do with the 
information if I had it. The satellites are where they are when I'm out 
surveying, there's nothing I can do about the positional accuracy. It's 
usually pretty obvious when a track has gone wildly off (usually due to 
woodland cover or urban canyons), and I'm still generally going to use 
the track otherwise.

David