Hi.
I understand your sketch of how-to-map-the-shops; but What's the real
benefit?
If there are the value for a "shop-width-unit" in OSM already, someone
worked that out in the past - why shouldn't he add the individual nodes
for the shops instead of helping other mappers to do it later?
The usual case will be, that this unit is different at least from streat
to streat; often perhaps from street segment to street segment.
That in mind I don't think it's really useful.
There ARE already mechanisms to divide housenumber-interpolations to
individual nodes (e.g. in JOSM) for an estimated positioning of these.
regards
Peter
Am 23.11.2010 16:23, schrieb Laurence Penney:
On 23 Nov 2010, at 05:47, Steve Bennett wrote:
On Tue, Nov 23, 2010 at 7:57 AM, Laurence Penney<[email protected]> wrote:
I think it would be particularly useful to demonstrate that the whole of a row
of shops has been surveyed. After taking account of the units tag, any gaps in
a line of nodes - on a fully surveyed street - could be taken to be private
houses or empty space.
If that's the most compelling use case, surely there are more direct
ways of indicating this, like a note=*? I can't see how a renderer
could ever make use of the units=* tag, so it's essentially only for
other mappers anyway?
I am indeed thinking of other mappers rather than renderers.
One reason I'd like it in a predictable place (either units=* or width=*) is to
facilitate an app whose purpose is to populate all the shops along a street.
For example, it would be nice to gather all the shops along Oxford Street:
http://www.openstreetmap.org/?lat=51.514746&lon=-0.146429&zoom=18&layers=M
My imagined app would first work out what street one was walking along using
GPS. Let's say it determined you were walking east along Oxford Street. It
would then divide the area around you into segments:
* North side: Marylebone Lane to Vere Street
* North side: Vere Street to Chapel Place
* North side: Chapel Place to Old Cavendish Street
* South side: Sedley Street to Woodstock Street
* South side: Woodstock Street to New Bond Street
* South side: New Bond Street to Dering Street
It would detect (or ask you to declare) which segment you are in, and then
suggest you add POIs for all the shops by presenting a list of blank slots. It
might start off with a default ~7m shop unit width, adjusting the
width-per-unit as more nodes are placed into the space. Declaring a shop as
width=2 units would get the node placed in the middle.
Here's a before& after:
|-------------- SS2
|
|
|
M
|
|
|
|-------------- SS1
|
Let's say, as you walk north up road M, the app determines there are 7 shop
units available between sidestreet SS1 and sidestreet SS2. It presents 7 input
boxes for you (prefilling some with any shop POIs found).
|-------------- SS2
| N5
|
| N4
M
| N3
| N2
| N1
|-------------- SS1
|
Here's the same street after I've walked up it, filling in 5 of the 7 boxes
with shop POIs (marked N1..N5). For shop N4, I've declared width=3 units
(perhaps by dragging an input box larger in the app's UI), so the node is
placed in the middle of the space it takes up on the ground.
Regarding using addr:housenumber for this, it's not going to work where the
numbers increase non-linearly, which is nearly everywhere. Also won't work
where the large buildings (which might be themselves 3 or 5 shop units wide)
have numbers. Shopping malls are problematic too - the numbers for the shop
units are often difficult to find out. I'd also like to map half-units and
one-third-units, which are quite common - and share a housenumber.
Regarding using the building outline, I'm not convinced it's useful to add
buildings where you cannot see the back.
One cool thing about such an app would be that its main UI would not be a map, just a
list of input boxes. Mobile mappers would NOT be placing dots on maps - something I've
tried (and hate) with Mapzen POI Collector. Having a 2D UI for this kind of POI placement
is suboptimal! The two dimensions of node location, which needless to say are easily
converted to latlong, are: interpolation between sidestreet junctions with the main
street, and a default "distance of shop frontage from road centre" with
override.
I can't think of any quicker way to survey entire streets of shops into OSM. Is
anyone else interested in developing such an app?
- L
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