[OSM-talk] [tagging] Feature Proposal - RFC - landuse=conservation

Tim Berners-Lee timbl at w3.org
Fri Jan 9 15:46:15 GMT 2009

I'd like to propose a tag for conservation land -  land protected from  
There was no alternative for tis tag in the thousands of areas which  
imported recently from the Mass GIS database of open space in  

Details below and on the wiki at:


Tim Berners-Lee



Conservation land is land protected from development.

It is left in more or less a natural state.

It is often maintained to a very limited extent, such as annual mowing  
to prevent forest growth, removal of invasive species, replanting, or  
dealing with or preventing erosion.

The public typically, but not always, has access, as it is a valuable  
recreational resource. (Sometimes the public has no physical way of  
getting to it, or is not allowed for water protection reasons, safety,  

There is often but not always a long-term commitment to preserve the  
state of conservation land over a long timescale. This is necessary  
because is is difficult or impossible and very expensive to re-create  
conservation land. (See protected=perpituity when and if it is proposed)

    * It is very valuable for individuals to be able to find open  
space for hiking, walking, cross-country skiing, or simply relaxing  
away from the buzz of the city. Conserved lands are a destination in  
    * In the suburbs, open spaces may be dense enough to be  
connectible into strings which allow for a long outing. In the Greater  
Boston area, for example, there are a large number of conservation  
areas, but the paths between them are not well signposted (as they  
would be in the UK or Switzerland, for example). The OSM provides a  
valuable resource for those building up a walk, or training run, from  
various different parcels.
    * It is very valuable for those studying humankind's effect on the  
environment to be able to find, measure and do research on areas where  
it has specifically been minimized.
    * Information on conserved lands is essential in the planning of  
greenways. Greenways -- chained areas of openspace with public access  
-- are often a mixture of national and local effort, and OSM can form  
a common resource in their development.
    * Open space management is an important aspect of government at  
each scale. Although many governments have databases of openspace  
resources, the OSM can integrate data from different countries and  

Many conservation areas have no other land use: to tag them as "nature  
reserve" or "park" would be misleading. In a way the essence of  
conservation is to limit use to non-damaging visits by the public. (Is  
it logical to use the landuse tag even though it is a sort of lack of  
use? Of course, just as one can have access=no. While it is as much a  
restriction on land use as much as a land use, it certainly belongs in  
the landuse key.)

Remember that tagging something as landuse=conservation is orthogonal  
to tagging it with its natural state of woodland, heath, marsh,  
wetland, and so on. In general you can't deduce the natural state of  
land from the fact that it is conservation land.

There are many general benefits shared by typical conservation lands.  
They may provide benefits to humans, to wild animals and pets, and to  
plants. They provide a habitat. They allow animals to safely move  
around without human interference. They typically reduce the load on  
the land. They allowing water to drain into the ground (rather than  
drains) promoting the water table. They form sound barriers. They  
reduce light pollution, allowing suburb-dwellers to see a few stars.  
And so on. So the actual uses of conserved lands are many. The actual  
profile varies from parcel to parcel, so the landuse=conservation tag  
covers many things, which it is not practical to individually tag on  
the map.

In the UK, the National Trust has the power to protect land from  
development in perpetuity.

    * The Lizard and Kynance Cove

In Massachusetts, the state Department of Conservation and Recreation  
(DCR) manages a number of conservation lands , as does each town such  
as the town of Sudbury:

    * Town of Sudbury owned Conservation lands

(Note this only lists those owned by the town, not all the ones IN the  

    * Hiking resources managed by Massachusetts Dept of Conservation &  

In Germany, this proposal matches the definition of  
"Landschaftsschutzgebiet". A tag for this sort of area is currently  
Rendering ideas

In the latitude of the examples, open space is often actually a rough  
green, one might think of the green of open heath, wild grass, ferns  
(bracken), and so on. Clearly it should be green, as that is one of  
the most important things about it.

As the fact that is it conservation land does It should be paler than  
the green used for a forest. It could have more yellow in it to  
suggest the wildness, and to distance it from the slightly bluey green  
which is currently used for farmland by some renderers. Yellow is also  
a color associated with open access land by the Ordnance Survey maps  
in the UK. Maybe adding a translucent lime-green wash to underlying  
colors from the natural state would work.

How is this different from a ...


A park is specifically maintained at a higher standard than  
conservation land. It may have mown grass, ornamental features, and so  


A nature reserve has a primary goal of preserving specific species of  
plants or animals.

What wouldn't you tag landuse=conservation ?

    * Land explicitly adapted for specific sports, such as soccer  
fields, golf courses.
    * Commercial forestry land

See also

    * Massachusetts Openspace layer

    * MassGIS Openspace layer

    * Primary Purpose codes in the above

    * C. Schmidt's code mapping the above to OSM

    * National Trust: Conserving nature

    * UK Guide to Greenways

    * Massachusetts DCR: Guide to Greenways


This was proposed while importing the OPENSPACE layer of the  
Massachusetts GIS data into OSM. There are 34,000 conservation area in  
the dataset, a large proportion of which deserved landuse=conservation  
The tag has been associated with features MassGIS marks as  
PRIM_PURP=C, for example.

The need arose earlier when adding open space to the map by hand.

Tim BL

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