[talk-au] Vicmap data copying

[David Bannon]

On Sat, 2014-05-17 at 22:12 +1000, Steve Bennett wrote:
> Hi David,
>   The policy shift you're advocating is enormous......

No, no Steve, I worded my last letter really badly and totally apologise
if I unintentionally offended anyone. My comment related specifically to
your line -

> Yeah. I'm still deciding what to do about places where Vicmap shows a
> track in the bush that can't be seen on any imagery - probably because
> the vegetation is too dense.

I meant leave the 'grey' areas to the survey people. There are many
roads (and particularly tracks) that cannot been seen clearly on the
imagery, and many more where some parts cannot be seen. I'd rather the
people working with imagery or other non (recent) survey data such as
Vic Maps did not make "educated guesses" but go and have a look, or ask
some else to go and have a look. 

I have had a road (into a new estate) removed, apparently because it did
not show up on Bing. Very annoying to a new owner there who was
directing tradies via OSM ! But that in no way means I don't value the
armchair mappers contribution. I'd just like them to double check their
data, one way or another before committing.

Maybe what we need is some sort of register ? The people studying
imagery are good at picking up anomalies, differences between image and
map. They could log it and have some local go and check ? Better than
just jumping in.

You may be amused to know that some years ago, I was shocked to discover
I had apparently built my house in the middle of the Bendigo Region
National Park. I was waiting to get a letter telling me to move it when
I realised someone had just followed the tree line, assuming all was
national park. They had swept up the Park it self, the Welsford State
Forest, Sugarloaf Conservation Park and a large number of private
properties. A very quick check would have prevented that error.

I am pretty sure all we want is for the database to have accurate,
relevant data. 

David


On Sat, 2014-05-17 at 22:12 +1000, Steve Bennett wrote:
> On Fri, May 16, 2014 at 8:31 AM, David Bannon
> <dbannon at internode.on.net> wrote:
>         Guys, can I respectfully suggest that source=survey ? Vicmaps
>         (and
>         
>         others) sometimes show roads that have been closed, land sold
>         off etc.
>         Those roads will show up in imagery because the car tracks
>         last a long
>         time on the ground. Further, visiting the site can clarify the
>         state and
>         status of a road. Road names on published maps are sometimes
>         wrong, lets
>         not propagate those errors !
>         
>         Lets restrict mapping via imagery to those situations where
>         survey is
>         not possible.
>         
> 
> 
> Hi David,
>   The policy shift you're advocating is enormous. You're proposing
> that virtually all armchair mapping cease, that the rate of OSM
> mapping be reduced by 100x, and that many contributors essentially
> stop mapping.
> 
> 
> Naturally, I oppose this suggestion :)
> 
> 
> You seem to be falling into the trap of assuming there is some kind of
> "aerial imagery vs survey" choice. Obviously the best thing for OSM is
> both. 
> 
> 
> Advantages of aerial mapping:
> - many times faster
> - more accurate than GPS traces in some/many/most cases
> - contribution from people for whom site surveys are not
> practical/possible/desirable
> - quickly do the groundwork so a site survey is more efficient and
> focuses on relevant details
> 
> 
> Advantages of site surveys:
> - get details that can't be obtained from the air
> - GPS traces more accurate than aerial mapping in some/many/most cases
> - fun (for some people)
> 
> 
> Me, I do a lot of aerial mapping. When I'm out and about I try to use
> what I've seen to update OSM. But I don't travel hundreds of
> kilometres out of my way just to do a bit of site surveying.
> 
> 
> In summary: let the aerial mappers keep doing their thing, let the
> ground surveyors do their thing, and let's work together for the good
> of the project.
> 
> 
> Steve