Proposed features/Reserve

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Status: Draft (under way)
Proposed by: Alex McKee
Tagging: boundary=reserve
Applies to: polyline, relation
Definition: Boundaries of reserves
Rendered as: Not in scope
Drafted on: 2010-03-08
RFC start: 2010-03-08
Vote start: Never
Vote end: Never

Why this page exists

I believe there is a need for this tag and as such intend to use it. However, in the spirit of OSM, I thought I should document the tag.

The need

We currently have various ways of putting nature reserves and other reserves into OSM. I believe they are unsatisfactory as I will outline below. As OSM becomes more sophisticated complex patterns have emerged making use of all OSM data primitives to provide satisfactory outcomes to problems like mass transit, addressing and various other challenges. I think it's time to take reserves as seriously.

The Landuse Problem

As various other proposals over the years have noted a polygon approach to reserves using the leisure=nature_reserve tag creates a significant problem of overlapping polygons. As OSM has grown more detailed this problem has grown more acute.

The usual example is that of a lake or wood inside a nature reserve. You could use multipolygon relations to resolve this problem but the lake or wood are not outside the nature reserve but are in fact constituent parts of the reserve. A more semantic way of describing the reserve would be to use the boundary key.

The Leisure Problem

The existing tag for nature reserves exists on the leisure key. Whilst this is unfortunate from the perspective that not all nature reserves are leisure facilities OSM users have worked around such minor semantics for years. A more serious problem, however, is that the tag is also inconveniently narrow. Land is reserved for many purposes: conservation, archaeological interest, leisure and heritage to name a few.

The solution

boundary=reserve is intended to represent all forms of reserved land although it is not intended to cover reservations. Specific sub-types of reserve can be specified using the designation key.

The tag is not intended to imply any access rights, these can be recorded separately using the aforelinked key. Nor is it intended to imply legal protection or the specifics of how the reserve is operated - these should be recorded using the designation key.

Why boundary?

Land set aside as a reserve does not necessarily have any physical properties that demarcate it as such. Most reserves, nature reserves in particular, are simply lines drawn on a map. Such lines are best represented in OSM using the boundary tag.

The use of a consistent boundary value, reserve, will lower the barrier to participation and furthermore allow an unsophisticated way to render all types of reserves. More specific renders can render different types of reserve differently based on the designation.


Local Nature Reserves

As mentioned above local nature reserves around the world vary hugely in protection, quality, legal status and access rights. As such specific designation should be recorded on the designation tag and understood in the context of the geographical location of the reserve.

Map the boundary of the reserve as a polyline or relation and tag as boundary=reserve + designation=Applicable legal status


In the UK there exists a type of reserve known as an SSSI, a special site of scientific interest. It isn't possible to represent these in OSM using the existing nature reserve tag. SSSIs do not exist for leisure purposes and are often unmarked at site. However the information on where such reserves exist can become available to OSM through individuals such as myself who have personal knowledge of SSSIs or through data imports. Using the operator key we can record who is responsible for the management of the site and the physical characteristics of the site can be recorded properly already using appropriate natural and landuse tags.

Map the boundary of the site as a polyline or relation and tag as boundary=reserve + designation=sssi

Country Parks

In the UK and Hong Kong Country Parks are areas of land reserved for recreational purposes. Unlike parks they aren't formal and aren't necessarily anything similar to parkland in any form. Tagging these as parks would introduce significant complications in the rendering of parks in the conventional sense. Also, like nature reserves and other reserves, there is normally a wide range of landuse and natural features within a country park.

Map the boundary of the country park as a polyline or relation and tag as boundary=reserve + designation=country_park.

Marine Reserve

Various countries now have marine reserves. Some of these have been added to OSM as national parks. National Parks are a specific form of legally protected land and have similar status in most jurisdictions. Most marine reserves are not created using national park legislation although some are. The ones which are should indeed be tagged as part of their respective national parks. However marine reserves not created using national park laws could be tagged as boundary=reserve + designation=marine_reserve. More specific designations should be used if applicable.