Paul Allen pla16021 at gmail.com
Mon Sep 21 16:04:32 UTC 2020

```[Apologies if this was preceded by a partial reply.  Damned laptop.  Grrrr.]

On Mon, 21 Sep 2020 at 16:11, OSM <osm at bavarianmallet.de> wrote:

>
> Am 21.09.2020 um 14:54 schrieb Paul Allen:
>
> This isn't as simple as you make out.  Assume that I am at point A and
> wish to
> go to point B, which involves a "wild crossing" at some point between the
> two.
> However, there is a real crossing at point C, a mile beyond point B,  A
> router
> will direct me to travel to point C (a mile further than my destination)
> in order
> to cross the road there, so I can then walk a mile back to B.
>
>
> You really walk a mile beyond and back again, knowing your destination is
> - say 10-20 m - across the street?
>

Of course I wouldn't do that.  What I would do, if a router told me to do
that, would be complain that the router was broken.

Or do you not know that your destination is at the street you walk along?
>

If I knew the details, I wouldn't be asking a router.

Back before I had even heard of OSM, I wanted to make a bus journey.
So I went to Google Maps.  I knew the bus route.  I had found the
destination.
I knew where I was stating from.  What I received was a ridiculous answer
that involved me walking a mile unnecessarily.  That was because Google
knew where timetabled stops were but not where the untimetabled stops
were.  It also didn't know that, along most of the route, the bus would stop
upon request whether there was a bus stop there or not.  So rather than
calculating the time to where the bus went past my destination, it
calculated
the time to the nearest timetabled stop (a mile beyond) and then the time
for me to walk the mile to my destination.  It was not very useful.

>
> I call those assumes a 'theoretical island problem'.
>

I call them an "I want the correct answer, not a damned stupid answer"
problems.  I don't want a router to give me a damned stupid answer
because if it does there is no point using it.

> a) Your point A is as near at point B, that you know or can estimate where
> you have to cross.
>

Yes, I can avoid using the router because it gives damned stupid answers.

c) Most routers have a display - and the view should show your destination
> (or route path to) across the street.
>

So they'll show me a damned stupid route to my destination.  Just as Google
did all those years ago.

--
Paul
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tagging/attachments/20200921/abf63bed/attachment-0001.htm>
```