[Tagging] landuse=farmland and highway=track

Warin 61sundowner at gmail.com
Sun Jan 10 10:08:41 UTC 2016


On 10/01/2016 8:23 PM, Dave Swarthout wrote:
> Haha, welcome to the club. This is a problem everyone faces. Here in 
> Thailand I spend a lot of time breaking up large wood multipolygons 
> because in the early days folks did not take the time to do it right. 
> Woods do not cover highways (unless its a farm track) nor do they 
> cover water features like river valleys or reservoirs. I can tell you 
> this, it's a lot of work either way you decide to do it but future 
> mappers will thank you if you do it properly in the first place.
>
> I have found the Fastdraw plugin to be helpful but only if you're 
> wanting to follow outlines accurately. The tool takes a while to 
> master and it creates many more nodes than would just a quick outline. 
> Take for example an area I just "enhanced" - the wood polygon north of 
> the junction of 1045 and 1047 was originally comprised of about 12 
> nodes. After I traced the southern edge of the wood more closely, it 
> now contains 966 nodes. Imagine how many nodes and how much time would 
> be required to do all the wood multipolygons worldwide. It's 
> off-putting to say the least.
>
> http://www.openstreetmap.org/search?query=%2017.7009941%2C%20100.6239762#map=15/17.6990/100.6190
>
> It looks better and is more accurate but takes up a lot more space on 
> the server. And it took a few patient minutes to trace. YMMV
>
> Cheers,
> Dave
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>
> On Sun, Jan 10, 2016 at 3:21 PM, Gerd Petermann 
> <GPetermann_muenchen at hotmail.com 
> <mailto:GPetermann_muenchen at hotmail.com>> wrote:
>
>     Hi all,
>
>
>     I am currently (armchair) mapping rural areas in Japan, that means
>     realigning nearly all
>
>     existing ways.
>
>
>     Whenever I am mapping landuse=farmland areas I wonder whether I
>     should
>
>     1) draw one rather large polygon stretching across all
>     highway=track ways
>
>     and small buildings which are likely used by the farmer and
>     waterway=ditch ways or
>
>     2) draw small polygons so that none of these objects is "covered".
>
>
>     Obviously option 1) is easier and results in rather few landuse
>     polygons while 2) is
>
>     much more work and results in many typically nearly rectangular
>     shapes.
>

Having spent many hours recently mapping State Forests, national Park and Conservation areas in NSW, Australia ... some comments...

Some of these are multipolygons with nodes over 3,000 on the outside. None of them are  orthogonal for all edges.
The data shows the easements for roads. Unless the easements are very large I have left them off... can only do so much in the time available.

I take the view that residential areas are drawn over an entire area .. and then roads, parks, buildings are drawn over the top of it. I think the same should occur with other things.

The existing multipolygons have taken no account of roads nor streams of any description.

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