In OSM edit mode, I recently found parking lots nearly filled up with neatly arranged points for street lights, trees, fire hydrants, etc. They seem to create a lot of clutter. Are they somehow needed?
The points are located on and near a Yale University campus. It may be that some college student had nothing better to do. If the object points are not needed, would it be ok to delete them?
They might be not needed for your purposes, but if they are really there, please do not remove any objects from database.
This kind of accurate mapping small objects is called micromapping:
The definition of what is important depends on the mapper. As long as it is true, verifiable, objective, and long enough lived, it is OK, but there is no obligation on you to add such features.
I won’t delete the objects I mentioned.
I’m new to OSM and mapping, but my opinion on minor objects is that due to the current margins of error, when added together, mean that a small object’s actual location may be so far from where the database locates it, that the location info would probably be useless for any purpose I know of. As I see it, potential errors would include background map mislocation, the OSM mapper not placing the object in the exact spot as shown in the background map, and the map user’s GPS receiver having a varying accuracy, up to perhaps 50 feet. I assume some of those errors will be reduced in the future, though.
With current aerial imagery it’s easy to get proper location of objects with ~0.1 m margin error, which is good enough even for street lights, trees, fire hydrants, etc. Fire hydrants on OSM are used by fire services in some countries, for example.
The objects should be placed to ensure correct small scale geometry. That means that, if the surrounding area is offset from the true WGS-84 position, they should be offset by the same amount.
In addition to what others have replied, the position relative to nearby features (is it to the left or the right of this road) as well as the existence and attributes of the object are often more important for an entry’s usefulness than the absolute error.