# [Tagging] importance=* tag (for transportation etc)

Andy Mabbett andy at pigsonthewing.org.uk
Fri Mar 25 16:36:30 UTC 2016

```On 25 March 2016 at 12:19, Alexander Matheisen
<AlexanderMatheisen at ish.de> wrote:
> Am Freitag, den 25.03.2016, 11:26 +0000 schrieb Andy Mabbett:
>> On 20 March 2016 at 00:12, Alexander Matheisen
>> <AlexanderMatheisen at ish.de> wrote:
>>
>> > If you have a look at the highway=* tagging: This scheme is
>> > subjective,
>> > but there is no alternative.
>>
>> Poppycock.
>
> Why?

For the reason I gave in an earlier post: it is often an objective,
verifiable legal designation.

>> > It is not possible to calculate the importance
>> > of a station just by some values.
>>
>> How do you calculate it, then? Rolling dice?
>
> I do not use any calculation based on measures?! My proposal (seems
> that you did not read it) uses a list of characteristic criterias for
> each category.

You seem to mean different things by:

* values
* measures
* characteristic criterias [sic]

> The scheme I propose can be compared to the place=* scheme.

> This definition also mentions "important", so where is the difference
> to the importance proposal?

The former does not try to quantify importance. It uses the term
descriptively in the page about the key, not as the key.

> And why is importance=* so problematic from
> the view of some mappers, while we are also using a similar scheme for
> places?

We are not; and for the reason given earlier in this thread.

>> > I also see problems in getting some of the proposed values. For
>> > example, the amount of passengers or trains per time is difficult
>> > to
>> > measure for a mapper and is not easy to be checked by other
>> > mappers.
>>
>> Please explain what measure you are using, that is *more easily
>> checked* by other mappers.
>
> If you think that the number of passengers or trains is easy to map in
> a larger scale, then please describe how you would map these values.

>> > I also see the problem that calculating the importance by a complex
>> > algorithm might be very intransparent.
>>
>> Please explain what measure you are using, that is *more
>> transparent*.
>
> As I said, I do not use any calculation based on measures.

> My proposal
> requires that a mapper classifies a station to one station category. It
> is more transparent because everyone can see that a station is tagged
> with a certain category. So a user easily understands why e.g. a
> station is rendered in a certain zoom level or was recognized as more
> important in the ranking of search results.

Then the tag would be transparent, but not the means used to arrive at it.

> If you just calculate the importance from a list of measurable values,
> you may get good results with a complex algorithm that recognizes many
> aspects. But then it is very difficult for a mapper to understand why
> station A was ranked more important than station B, and it is also
> difficult to influence the ranking if it is wrong. That is what I mean
> with transparency.

So long as the algorithm is published, it would be entirely transparent.

--
Andy Mabbett
@pigsonthewing
http://pigsonthewing.org.uk

```