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I recently joined OSM to help maintain maps in the area I live. I discovered tonight that someone painstakingly added polygons for many wooded areas that seem to me to be unnecessary considering the data that has to be read to draw them. An example is here:

Is this level of detail really needed, or even desired on OSM??

asked 02 Nov '12, 07:55

VermontFatBoy's gravatar image

accept rate: 0%

edited 02 Nov '12, 10:15

Pieren's gravatar image


First, the way you are pointing is dated of July 2010. It's not really recent.

The question about level of detail is a long-standing debate in OSM. Some people are just interested by motorways for their car navigation system. Some others want to add hospitals and related parking areas for their grandpa. Or map in details funparks, zoos. Others want to say which amenities or shops are accessible for wheelchairs. Mountain bikers or hikers want to know the difficulties related to a countryside path. Etc, etc.. So the level of details is all related to the level of interest and motivation from the contributor. Of course, one disadvantage of high details is that it becomes harder to maintain in the future. This is a pending issue. At the moment, we tolerate details if they are not excessive like 20 nodes to describe a small curve. Or attributes that are really not related to the OSM project itself (e.g. price lists). In other cases, we all appreciate that the level of details is increasing in parallel with accuracy with the number of new contributions. What is not acceptable is that someone downgrades the quality of other's contributions just because he doesn't like so much details on his map. Don't forget that the main slippy map displayed on is mainly for contributors. Other web sites may choose to render less details on their map if they want a more readable map. But that is a rendering and design decision, not something you can decide for others in the database content itself.

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answered 02 Nov '12, 10:14

Pieren's gravatar image

accept rate: 15%

edited 02 Nov '12, 16:49

At last, a definitive answer; 20 nodes for a small curve is excessive (and I don't mean that as a sarcastic comment - it genuinely helps). Could you possibly look at my mapping of Meadowband Road ( and tell me whether I have used an excessive number of nodes to try to get it to render as a smooth curve?

(02 Nov '12, 20:17) Madryn

@Madryn: In my opinion, an additional node that has significant visible effects even with the relatively coarse resolutions rendered in the default Mapnik style is rarely excessive. Your mapping is nice and anything less than that would not fully represent the actual shape of the roads. Ultimately, simplifying a way should be easier for applications than adding detail that isn't in the data.

(02 Nov '12, 21:15) Tordanik

Thank you for your helpful answer. I was in no way intending to delete the hard work done by someone else, but it is kind of irritating (maybe it's a little OCD on my part) that one town has a lot of detail when a neighboring town does not. Guess I'll have to live with it unless I want to add wooded areas in my town as well.

(03 Nov '12, 00:04) VermontFatBoy

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question asked: 02 Nov '12, 07:55

question was seen: 2,934 times

last updated: 03 Nov '12, 00:04

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum