> adding check timestamps as string tags for every single tag seems a lot of > bloat. One tag per object for me would be acceptable because it is indeed a > valuable information when something was last verified and no changes were > necessary.
Definitely it has the potential for that. And as Mateusz noted in another branch, check_date tags themselves could become out-of-date if successive editors do not update the tag together with the tag it refers to. On the other hand, at least at this time I do not see the danger of this [=every single tag is accompanied by a meta-tag] happening, neither through individual usage of such meta tags nor by being set by StreetComplete automatically because only a small fraction of tags are likely to change in a timeframe of some years or below. In other words, only for a small fraction of tags it makes sense to attach a check_date to. A good example of things that change more frequently would be smoothness or opening hours. For example one surveyor may check on-site the smoothness and surface of a road, but not check if the width is still correct because he doesn't have anything with him to measure it. Also, he doesn't want to check if the speed limit is still correct because that would require him to go up the road at least until the next big intersection to find a speed limit sign (or not). He may also not want to check whether all(?!) the bus routes are still correct. Generally, some information tagged on an element is also not verifiable on-site. What this example should illustrate is that it is illusory to assume that a mapper is both able and willing to check everything at once for a certain element. (Basically, StreetComplete is founded on the idea that surveyors don't have to tag and check "everything" at once for any given element but add/update the information bit by bit.) --- On the topic of map maintenance, there is another information that is currently missing (from the API) which would be helpful to maintain an up-to-date map. It is a bit off topic because this topic is mostly about StreetComplete / on-site map maintenance but I would like to still touch on it shortly: If the date + *source* of the last change made on (the geometry of an) element was readily available, through the API or another meta-tag (source=bing, anyone? ;-) ), this would help to identify areas that should be updated because a new more current and/or detailed source became available. In Hamburg, we are lucky that the public authority provides us with really detailed up-to-date satellite imagery that are far beyond bing but there is no easy way to see which buildings and road geometries have still been mapped on the basis of bing and which are already using the better source. So in a nutshell, the topic of how to find things based on old sources is also very relevant for remote mappers. Cheers Tobias _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
