[Talk-GB] Mass edits of landuse /natural tags

John Baker rovastar at hotmail.com
Thu Apr 25 15:23:47 UTC 2013


To be honest I am struggling to see anything wrong with what I have done.
Let take grass in your example Jerry.

There are always more suitable tags than natural=grass, landuse=grass being the most obvious there is also natural=grasslands as was pointed out by Tom. I am aware of these. I am surprised at the assumption that I am not.

Now I said I did not update if there was an existing tag. So for landuse=farmland I left it.

But if there was no existing landuse tag what is the harm?

Even if a soccer pitch was changed from natural=grass to landuse=grass what is wrong with that? It still states in the tag that is is grass. It was tagged "wrong" to being with as it should be surface=grass but now it will be tagged slightly less "wrong" as it is at least following some standards.

None of the cases mention I can see that I did any harm. 

And I do tag the landuse/natural for Nature reserves. Why would you not? Why would you leave off information. If the nature reserve is grass, scrub, wood/forest I tag this too. I might/do breakdown the different areas of of the reserve. There is no conflict with leisure=nature_reserve and other tags.

When we say discuss things on the mailing list surely then this goes both ways. I personaly object to others using their own tagging system when there is a well established tagging system in place already. If only 1 person decides to use non standard tagging like natural=grass where more useful, appropriate and standard tagging applies then that doesn't help anyone, in fact I think you should stop as *that* defeats the point of the tags and use what everyone else uses. If you really want this put in an RFC for the wiki and get it more standardised.

If anyone has specific examples about where I made a mistake let me know. I cannot believe there will be many at all and the benefits of doing these changes are IMHO largely beneficial to the map.

Cheers,

John
Date: Thu, 25 Apr 2013 14:19:39 +0100
Subject: Re: [Talk-GB] Mass edits of landuse /natural tags
From: tom at acrewoods.net
To: sk53.osm at gmail.com
CC: rovastar at hotmail.com; talk-gb at openstreetmap.org

I can sympathise with some of what Jerry, John and Frederik have said here.
There is undoubtedly a lot of slightly inappropriate tagging in the database, meaning that serious use of the data often requires a lot of cleaning up. I went around Southwark changing lots of land uses but based on surveys and where it was clearly wrong, so that I could do some analysis and make nice maps of green spaces in the borough. It used to be the case that landuse=recreation_ground was _the_ way that we all tagged any green space that wasn't a park. I routinely change these to landuse=grass when I come across them these days, unless they really are recreation grounds. I wouldn't want to be held back by having to divine (or enquire about) the intention of the original editor each time!

It's also annoying when the tag Jerry is looking for, according to the wiki, is "natural=grassland" not "natural=grass" as you would expect:http://wiki.openstreetmap.org/wiki/Tag:landuse%3Dgrass


Also the tag "natural=meadow" has been merged into "landuse="meadow". There is now another key "meadow=agricultural/perpetual" (oh joy) to distinguish between managed and unmanaged meadow, or what used to be the natural/landuse split!

There is, in general, a longstanding confusion about natural/landuse. The natural=wood/landuse=forest use is pretty interchangeable across the UK, so that we can only really treat them as equivalent and meaning "some trees".

The problem that John, Jerry and I have all run into is the downside of a free tagging system without a mechanism to iron these wrinkles out. We can only really shrug our shoulders and accept that the data is really patchy in terms of coverage and appropriate tagging, and do our best to improve it after discussion. Incidentally, if you want to see a real basket case of a key, look at the values in Taginfo for the building key!

As Frederik said, it is best to discuss ideas for large scale corrections on a mailing list first. That way these issues come out and can be discussed before the edits, clean-up strategies can be improved, and people don't get upset at mistaken edits no matter how good the intentions.

John, I would suggest that you inspect each natural=grass object on a case by case basis to try and determine which of these it best fits:http://wiki.openstreetmap.org/wiki/Tag:landuse%3Dgrass


Regards,Tom

On 25 April 2013 13:59, sk53.osm <sk53.osm at gmail.com> wrote:

Why do you assume that landuse=grass is more correct than natural=grass. This is precisely the problem I have with your edits. If I use natural=* for something someone comes and changes it to landuse=* which is not what I meant. 




I ONLY use landuse=grass for amenity grassland (mainly in cities) which would otherwise not be mapped. I would never use landuse=grass for grassland in a farm or a nature reserve, or on a sports pitch (we have a perfectly good surface=* for that). Unfortunately many people have used landuse=grass indiscriminately (for instance for farmland in Hollandhttp://osm.org/go/0E6w0ZK-- and here in Lancashire (the area around Garstang shows wholly inappropriate use of landuse=meadow too). It seems that people prefer the green colour rendering for these over the brown for farmland. I am unaware that landuse=farmland only refers to arable.




I don't know if you have heard of places like the Steppes & the Pampas, the American Plains, 
or the Serengeti, but there do exist large areas of the world covered by grasses which are natural!




You are not the only remote mapper to do this kind of change, xybot zapped one of my natural=grass tags.

Obviously I will now have to make my intentions absolutely explict with notes etc., which rather defeats the point of tags. Perhaps I should use SK53:natural=wood and then they won't get trampled on.




The problem is that you are anxious for everything to be rendered in a uniform manner, but you are not considering the many other use cases particularly for landuse/landcover data. Continuous tidying up of tagging in this area means that OSM is not currently a viable platform for serious use for conservation




Jerry
.


On Thu, Apr 25, 2013 at 12:48 PM, John Baker <rovastar at hotmail.com> wrote:





Just to be clear about what I am doing.

I have been changing many what I consider typos. The majority have been simple changes I started by cleaning up the lanes tag as I was doing work getting lanes tagged correctly for the new CartoCSS and lanes=90 (where they was not) and lanes=two made no sense. So I fixed each of these worldwide looking at aerial imagery, (e.g. needed so leave a lanes=27 or something for a massive border entrance)



Again inspired by my designing new style at doing CartoCSS styling I looked at other features that I has been doing, fountains, nightclubs, religions, ice rinks, etc

Then fixing some the nature, landuse tags, landuse=maedow to meadow, etc within the same tagtype.



Recently I wanted to tackle one of my biggest personal bugbears of natural=grass which is (now was) tagged incorrectly and should be landuse=grass. There where dozens/hundreds in my local area so I did the whole UK.



In case where I moved tag type (natural to landuse) I looked at if they added anything to the corresponding tag.
 
So if nature=grass already had landuse=park or something I didn't change it over.

Also I looked at the ways that had a name or had notes and decided if they where due more investigation and if to edit them or not. To be honest most didn't and it was quick and easy to check in JOSM when I highlight them all.



I tried to explain myself in the change set notes.

I like to think I have been responsible when doing this and think it improves the database/map.

http://www.openstreetmap.org/user/Rovastar/edits?page=1






> Date: Thu, 25 Apr 2013 09:20:32 +0200
> From: frederik at remote.org
> To: talk-gb at openstreetmap.org


> Subject: Re: [Talk-GB] Mass edits of landuse /natural tags
> 
> Hi,
> 
> On 04/24/2013 04:26 PM, John Baker wrote:
> > AFAIC these were typo edits and getting the whole database more


> > consistent. I have done dozens of changes to fix typos worldwide over
> > the past few weeks and it would be crazy to have lengthy discussions on
> > each one for multiple countries in multiple communication channels.


> 
> If you don't have the time or the will to do it properly, then simply 
> leave it be.
> 
> The rule is that as soon as you make an edit where you don't look at the 
> individual object you edit, it is a mechanical edit that has to be 


> discussed beforehand.
> 
> The reason for this rule is that it is too easy to introduce mistakes - 
> what looks like a "typo" to one person could make sense to another.
> 
> Assume that there's an object tagged landuse=forest *and* natural=meadow 


> *and* it carries a note tag that explains exactly what the mapper meant 
> by this. Someone simply looking for all natural=meadow and replacing 
> them with landuse=meadow would overwrite the landuse=forest and not even 


> see the note tag - he performs a mechanical edit that needs to be 
> discussed beforehand (in order to minimize undesirable side effects).
> 
> On the other hand, if someone were to manually go through all objects 


> tagged natural=meadow, read potential note tags, look at the other tags 
> and/or aerial imagery, and *then* change them to landuse=meadow, that 
> would not be a mechanical edit.
> 
> Bye


> Frederik
> 
> -- 
> Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"
> 
> _______________________________________________


> Talk-GB mailing list
> Talk-GB at openstreetmap.org
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