On Thursday 18 April 2019, Kevin Kenny wrote: > > I doubt very much that you're saying what you intended here. > > It comes across as saying, for instance, that lakes too big to map on > the ground in a single day should not be mapped, or should not be > named. I think that making large waterbodies disappear would be > ridiculous.
You apparently misunderstood what i said. My 'surveyable in a single day by a single mapper' rule of thumb refers to mapping something as a single feature. A river several thousand kilometers long for example. The river is locally still a verifiable element of the geography and can be mapped - piece by piece as it is generally established practice in OSM. But if you create a feature for the whole river extending over thousands of kilometers that is not something you do based on local knowledge, that is based on social conventions you have read up in a book, on wikipedia or elsewhere. As far as physical geography is concerned (so i leave out boundary and route relations here - which are a different thing) we have essentially only two types of feature that are generally accepted to be mapped with large relations: lakes and islands. Both of these were not always mapped this way - large lakes were for a long time mapped only locally - like the coastline. Both of these are technically unnecessary to be mapped this way (there is no actual information transported in assembling the ways into an MP relation) because their geometry derives non-ambiguously from the locally mapped water outlines. The decision to create MPs none the less mostly comes from the desire to have consistency with smaller features (which are obviously locally verifiable as a whole). Everything else in physical geography is typically mapped locally piece by piece like the rivers and creating large features - while done by some mappers for the purpose of label painting - is generally disliked by most mappers because it is very hard to work with these and represents no additional meaningful information. > Moreover, if you've mapped something on the ground, what difference > does it make how long it took? It is a rule of thumb. The rule itself has no meaning on its own, it is designed to make it easy to determine a reasonable limit. > I understand that there are fairly severe technological issues at > present, where a plethora of enormous multipolygons breaks some of > the software tools. My argument is not a technological one, it is a social one. Mapping only things verifiable based on local knowledge in OSM is essential for the social cohesion of the project across many different cultures world wide without creating an imperialistic dominance of some cultures over others. -- Christoph Hormann http://www.imagico.de/ _______________________________________________ Tagging mailing list [email protected] https://lists.openstreetmap.org/listinfo/tagging
