Am Freitag, den 25.03.2016, 11:26 +0000 schrieb Andy Mabbett: > On 20 March 2016 at 00:12, Alexander Matheisen > <[email protected]> wrote: > > > If you have a look at the highway=* tagging: This scheme is > > subjective, > > but there is no alternative. > > Poppycock.
Why? > > As the person who created that station importance draft, I will > > focus > > on stations, but for other features like mountain peaks the > > situation > > should be similar: 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. The scheme I propose can be compared to the place=* scheme. The tagging of places is also a kind of importance ranking. According to the wiki it is not based on population and it can be decided by the user to get better results: "By way of example, the charter city of Alameda in California (population 76,000) is tagged as a town, due to its proximity to the much larger and better known cities of San Francisco (populations 805,000) and Oakland (population 309,000)." ( http://wiki.openstreetmap.org/wiki/Tag:place%3Dcity) Also see this description taken from http://wiki.openstreetmap.org/wiki/Tag:place%3Dtown: "Use place=town to identify an important urban centre that is larger than a place=village, smaller than a place=city, and not a place=suburb. Towns normally have a good range of shops and facilities which are used by people from nearby villages." This definition also mentions "important", so where is the difference to the importance proposal? And why is importance=* so problematic from the view of some mappers, while we are also using a similar scheme for places? > > 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. For example see the number of passengers. In most cases railroad companies do not publish these information except for some big station. That means that a mapper would have to go to the station, stand near the entrance and count how many people go in and out. For larger stations you need more than one mapper to count this. And also if you are able to count the number of passengers, there are more problems: This value depends on time, so it would be necessary to do this more than once at different times, different days, etc. to calculate an average value. Do you think this is praticable? Another suggestion here was the number of trains. This can be done more easily, and if timetable information in standard formats are available, this value can be collected automatically. But the problem is, that this value does not indicate the importance of a station. A suburb station may have trains departing every 2 minutes while a central station may have trains departing every 10 minutes. But that does not indicate that the suburb station is more important. > > 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. 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. Regards Alex
signature.asc
Description: This is a digitally signed message part
_______________________________________________ Tagging mailing list [email protected] https://lists.openstreetmap.org/listinfo/tagging
