[OSM-talk] Potlatch doing source=GPS in error?

[Shaun McDonald]

The source tag has been in use for the past 3+ years and no one has  
made such a fuss over it as you.

The hdop and pdop will vary widely across the track, thus it would be  
useless adding it. Also what happens when you have many different  
traces. I for example have a few hundred traces from some of the  
streets that I commute to work on. What happens if I load a large  
portion of them for averaging a trace?

You are trying to to store more information than is useful, thus  
wasting space and processing time for people using the data.

Shaun

On 24 Sep 2009, at 11:46, John Smith wrote:

> 2009/9/24 Shaun McDonald <shaun at shaunmcdonald.me.uk>:
>> It does not matter if it is documented. When you read source=GPS  
>> you can be
>> pretty sure that you understand what it means.
>
> In this case survey and gps are synomonous, also I can't verify a GPS
> was in fact used if people move the way due to aerial imagery etc so
> it may not be a verifiable tag.
>
>> Also the source tag is a bit useless once several people have been  
>> along a
>> street and verified it, which is why I think that it should be put  
>> on to the
>> changeset instead.
>
> So why not use survey, since that would most likely be the most  
> accurate.
>
>> Things that are important will become consistent through usage. The  
>> source
>> tag is not an important tag, it is a freeform tag. The items on the  
>> map
>> features page just give some ideas of the values that you can use.
>
> If consistency is let lapse in one area it will go into other areas, I
> could use the same logic for slightly more important tags and state
> it's a free form tag and so on up the chain till I start doing my own
> custom set of highway tags.
>
>> P.S. I'm a bit of a perfectionist, however there aren't enough  
>> hours in the
>> day to be able to make tags that are absolutely perfect and get  
>> everyone
>> using them all consistently. You just need people to start using  
>> them. Then
>> when things break you can fix the tagging of the individual items.
>
> Unless you want to go to significant effort thaere is no point stating
> gps over survey. In fact stating GPS could be slightly misleading, you
> have no idea what type of gps was used, any additional techniques to
> improve from the talk-au list:
>
> gps_chip=antaris/sirfstar3/mediatek/trimble/
> gps_model=
> hdop=
> pdop=
> (precision would be some rough figure for the track, i wouldn't want  
> to see
> them on each single node)
>
> Unless all the above is present you don't have precision, or going a
> step further without surveyor type equipment you aren't going to get
> accuracy anyway.

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