[OSM-talk] Bing maps is misplaced

[Steve Bennett]

On Wed, Dec 22, 2010 at 6:27 AM, M∡rtin Koppenhoefer
<dieterdreist at gmail.com> wrote:
> yes, in you example you would have 100 wrong streets. I'm not
> believing your numbers btw.: I doubt that you can only visit and map
> 10 streets with the effort you have to put 1000 streets from
> orthofotos (1%). Even if this ratio was only 10% (in my experience
> mapping takes as long as surveying, which would result in 50% for no
> survey at all) I would prefer 100 reliable streets to a thousand of
> which a hundred are wrong. If there is no information, this is at
> least reliable in the sense that you know you can't rely on it ;-)

Well, you're welcome to your preference.

As to my numbers being wrong, it's probably the other way. When I'm on
a roll, I'm probably mapping a street from imagery every 5 seconds or
so. Click, click, click, "r", done. I don't know how long it would
take to drive up and down it (surveyors recommend at least two GPS
passes don't they?), then import, then trace, then tag. A lot more
than 50 seconds, anyway.

And it's not as if GPS traces give brilliant results anyway.

> A very good map can't be done just from orthophotos.

You thought I was saying the opposite? I would say a perfectly usable
map can be made just from tracing imagery: you'll have the roads, with
basic category distinctions, plus some footpaths, bike paths, parks,
carparks, buildings etc etc. There will be occasional mistakes like
driveways mapped as roads, incorrect junctions (ie, two roads that
pass near each other but for some reason don't join), missing gates
etc.

And of course you won't have names. For the way I use maps, that's
actually pretty acceptable: I tend to load them on a GPS and use them
for navigation to a known point. So, knowing about roads that connect
places is far more important than knowing what they're called or speed
limits or whatever. (Also, since I cycle, a lot of that extra
information about roads is irrelevant).

Of course, we don't build maps just for our own individual
preferences, but we're certainly biased towards including the
information that interests us personally.

Steve