Proposed features/fieldmargin

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Field Margin
Status: Draft (under way)
Proposed by: descilla
Tagging: landuse=fieldmargin
Applies to: Area
Definition: Areas around or between fields/farmland or meadows
Drafted on: 2014-07-12

Motivation

Tagging examples

In most regions of agriculture a lot of fields and meadows are surrounded or separated by strips of various plants (trees, grass, shrubs,...). These areas are called field margins/borders (in german: Feldrain).

Purpose

There are several purposes for field margins.

  • Firstly they support the diversity of species. Birds and other smaller animals are protected and also fed by these plants.
  • Secondly they are important for farmers. They can raise the crop yield because field margins are protecting surrounded fields from the impact of wind (soil erosion) and other meteorological effects.

Current situation

Currently these areas are mapped in several ways (some used tags are even inadequate for this purpose). Examples: landuse:meadow,forest,grass natural:wood,tree_row,grassland barrier:hedge and many more.

Tag suggestion

In my opinion there should be a way to tag these areas consistent but also give an option to tag it more detailed. Therefore I recommend the usage of farmland=fieldmargin combined with landuse=farmland because these areas are mainly managed by farmers. Furthermore by using a subcategory of farmland the landuse=* tag becomes/stays cleaner and more structured (cascading usage of landuse).

Tagging

In general only landuse=farmland and farmland=fieldmargin is needed to tag a field margin but you can use an additional tag to specify the type of field margin. Note: If the field margin is grown by several types, the additional tags can also be combined (separated by a semicolon).

Types of field margins
Tag Additional Tag Comment Example pictures
landuse=farmland and
farmland=fieldmargin
fieldmargin=grass Grass. The field margin is mainly covered by grass. Field margin south of Lebberston Carr Farm - geograph.org.uk - 558071.jpg Arable field margin at Bodney, Norfolk - geograph.org.uk - 358522.jpg Curved field margin - geograph.org.uk - 1055762.jpg Field margin, Tarlton, Gloucestershire - geograph.org.uk - 451126.jpg
landuse=farmland and
farmland=fieldmargin
fieldmargin=trees Trees (more than a few) Fieldmargin-wood1.JPG Fieldmargin-wood2.JPG
landuse=farmland and
farmland=fieldmargin
fieldmargin=hedge Hedges, close and even grown shrubs and/or little trees. Fieldmargin-hedge1.JPG Fieldmargin-hedge2.JPG
landuse=farmland and
farmland=fieldmargin
fieldmargin=scrub Shrubs/Bushes (not close/even enough to be a Hedge, maybe some grass between them.) Field margin - geograph.org.uk - 583665.jpg Field margin and bird scarer - geograph.org.uk - 1063335.jpg Field margin, south of Whitehill Lane, Grittenham - geograph.org.uk - 1209936.jpg The D'Arcy Dalton Way - geograph.org.uk - 213199.jpg
landuse=farmland and
farmland=fieldmargin
fieldmargin=wetland Wetland area as fieldmargin (wetland between two fields) Looking S along ditch on farmland near Plucks Gutter - geograph.org.uk - 463390.jpg
landuse=farmland and
farmland=fieldmargin
fieldmargin=wall An (earth-) wall currently no image
landuse=farmland and
farmland=fieldmargin
fieldmargin=<any value> Another type of fieldmargin.

Benefits

The consistent tagging of field margins has several benefits:

  • Firstly there is no specific tag for these areas at the moment.
  • Secondly unique tagging of field margins would be helpful for landuse researches/studies.
  • Thirdly this tag could assist outdoor navigation (easier localisation of "Where am I?" or "Is this way in front of or behind this hedge. (Okay, this is also possible at the moment, but see point four).
  • Fourthly this specific tag may raise the interest of mappers to map these areas (may more mappers will create smaller areas of farmland (one for every field) an field margins between instead of a huge landuse=farmland for several fields).
  • Last but not least point Five. By using a consistent tagging, renderers would be able to render these areas more homogenous (as far as I know this is a discussed problem of Mapnik at the moment) and/or they can use the parent-category as fallback if a fieldmargin=* attribute isn't known by the renderer.

Additional informations

This idea was also discussed on the tagging mailing list and in the german part of the osm forum.

Discussion

Feel free to discuss this draft. If you have found other types of field margins please let me know. --Descilla (talk) 14:06, 12 July 2014 (UTC)

Fieldmargins are almost always narrow linear structures. I would prefer to have them tagged more by using ways rather than by areas, optionally with a width=*. Consequently I don't consider landuse as the appropriate category (always area). I'd suggest natural. This is used for areas (wood) as well as for ways (tree_line). I think it's a better approach than the usual barrier=hedge. The barrier property is in most cases merely existent, at least not the main purpose. --Seichter (talk) 20:46, 14 July 2014 (UTC)

See above I modified the detailed tagging part (at least). I had two motivations for this proposal. Motivation one was to get a chance to map filedmargins as areas (In my region fieldmargins are often a combination of straight lines and "islands"/areas of trees or scrub soccasionally, so its not a line all the way). Motivation two was already mentioned by you. In my point of view the usage of barrier=* for fieldmargins is not correct because fieldmargins aren't barriers. (I added option 2 (fieldmargin=* only now, because some people on the mailing list told me that the usage of barrier=* for filedmargins isn't wrong. Apparently there are other opinions.) Thanks for your feedback. --Descilla (talk) 12:24, 15 July 2014 (UTC)
I have no objections against mapping fieldmargin as areas, I simply don't want to be forced to.
landuse implies area - I'm not allowed to map simple lines in trivial cases (e.g. a field margin of several hundred meters one meter wide)--Seichter (talk) 21:24, 15 July 2014 (UTC)


I consider the use of natural or landcover for additional tagging as not appropriate. They are used for first level tagging typically mutually exclusive. Common practice is to repeat the value as subtag key:

natural=fieldmargin
fieldmargin=hedge

--Seichter (talk) 21:10, 14 July 2014 (UTC)

I agree (that was also my opinion) See changed "Tag suggestion" part and answer to Seichter above. Thanks for your feedback --Descilla (talk) 12:24, 15 July 2014 (UTC)

A minor issue: Field margin is written in two words. That is usually expressed by underscore for tagging keys: field_margin.--Seichter (talk) 21:24, 15 July 2014 (UTC)

(Discussion on the talk page??? - http://wiki.openstreetmap.org/wiki/Talk:Proposed_features/fieldmargin)--Geri-oc (talk) 06:23, 15 July 2014 (UTC)