Hello all

Please could I askyour opinions about the best way to add areas showing housing in a suburban environment.

I’m currently drawing little polygons, a little way inside the enclosing roads, as this seems to be the way a lot of London has been drawn. I notice that if the polygon actually shares the nodes of the road, then JOSM complains about overlapping ways, so I presume that is deprecated.

However, I’ve also tried just blocking off areas, crossing over roads in the process. (for example here ) This is generally less work, and also possibly looks better as there isn’t a gap between grey ‘background’ and the road when zoomed right in. Is this way of doing things acceptable? Preferred? Going to break something?

Many thanks


There is no “right” way to do this. There are people who say you should draw the polygons inside the enclosing road, but there are also people that say you should reuse the roads. Both are equally valid.

However there are also people out there who think their method is the only one that should be used. This has lead to some long winding discussions on the mailinglists in the pasts. They didn’t give any definite conclusion though.

Nope, it’s not valid to use the road (assuming you have good enough aerial precision to see the boundaries), unless the road is part of the residential area.

Cool, how did you derive this decision for the whole community, when in the past there was never a consensus about this?

Correctness. Map what’s on the ground rather than an incorrect approximation.

I see . You are one of those: “However there are also people out there who think their method is the only one that should be used.”

I definitively agree with this, but with one addition: It is better to map something than nothing at all. Corrections can be made later if someone desires to do so.

But i does prefer to have a map that exactly represents the real world, but how do I map a forest then? Tree by tree? No, for that an rough approximation is better, else the GPS will never finish rendering!

I fully support this.

And I will also draw tracks over forest areas and not draw smaller forest areas between all the tracks despite the fact that there are for sure no trees on the tracks. Why? Because its common sense that there are no trees on the tracks and no buildings on the residential highways. And because a map is always an abstraction and never will or even should try to show all details of the real world.

In generell and in OSM there are many ways to do something and I prefer to use for each situation the way which I think is fitting best.

I think that I will quote you somewhere sometime when I think that it is appropriate.

I have also found this very good site that we could refer to in endless discussions.

I just think it is funny that some people demand that people map something with great accuracy, when by its definition it is a fuzzy concept. Note the word “predominantly” in the quote from the wiki below.

Hmm, I do not know what predominantly means (I’ll check that up soon, very soon), but I could guess (something dominates by larger part , in this case in an area).
In Sweden we have a database/map that shows specific land portions that has an identifying number, or how to say (like “nånby, nånstans 14:3”) this data could be used as a base for how to map residential areas. But for large-scale use it must be licensed, for pretty high rates (relative to the content of my wallet, anyway). These rates does however have a “roof” (no matter how much data you want, you’ll never havt to pay more than $$ ).

I do get your point - just map away and use your own judgement for how to map.

Sometimes one just want to map something out, but maybe not with that great precision - one other time you might want to have that precision. In any case, anyone who uses the data should not go around “blindfolded” and just rely on the data - they should also use common sense. If there is a river in the real world, but not on the map - don’t trust the map! Or else you’ll get yourself drowned.

Um, sorry if i’m being naggy or something.