Prehistoric Britain
Megaliths
Currently (September 2014) OSM data of UK megalithic sites is poor, with many sites unmapped. Furthermore the tagging of sites that are mapped is generally incomplete, using various and incompatible tags making it difficult for map renderers and applications to find and display. Some examples of tags currently in use;
historic=archaeological_site site_type=dolmen or site_type=bigstone
The aim of this project is to map the extant prehistoric man-made stone structures in the United Kingdom. As such we want to;
- Add missing megaliths to the map, using Bing aerial imagery or ground surveys.
- Make tagging consistent
- Make tags as complete as possible
- Add links to external sources of information - Wikipedia etc.
I propose the following schema to standardize the mapping of prehistoric megaliths in the UK, including a set of tags which, as far possible, follows the majority of the tagging schemas already in use for megaliths in the UK and abroad.
Mapping
Megaliths should be mapped with one of;
- a node at the centre of the site
- a closed way marking the perimeter of the site.
- a relation connecting a set of nodes or ways which mark structures in the site
At a minimum the following tags should be applied to all prehistoric megalithic sites;
name=*
historic:civilization=prehistoric
And one of;
megalith_type=dolmen For megalithic tombs, dolmens, quoits and cromlechs.
megalith_type=menhir For standing stones
megalith_type=alignment Stone alignments or rows
megalith_type=stone_circle Stone circles
If required, individual stones or structures can be mapped as closed ways and tagged;
Optionally, the following tags can also be used for individual stones (though these tags and values seem non-standard);
If individual or multiple stones are mapped, then either
a) an area around them should be mapped by a closed way (this may only be approximate), with the tourism=*, name=*, historic=archaeological_site etc tags.
or
b) they should be connected with a relation, which is itself tagged with the standard set of tags.
Dating
A distinction can be made between stone age and bronze age megaliths - in the British Isles the beginning of the bronze age is often stated as somewhere between 2000 and 2300 BC. However this is not a completely objective distinction - the 'bronze age' arrived at different times in different places around the globe, and furthermore the age of many megaliths in the UK are uncertain.
However, if there is a generally accepted era for a site then the following tags could be used;
For stone age sites;
For bronze age sites;
More specific dates can also be used, if they exist.
Access
access=yes Site is on public land or land over which the public has legal right of way.
access=permissive Site is on private land but is open to the public. The owner can at some time in the future revoke permission.
access=no or access=private Site is inaccessible to the public.
fee=yes Site has an entrance fee.
opening_hours=* Site opening hours.
operator=* The company or authority that runs the site, e.g. operator=English Heritage
Condition
Britain's prehistoric megaliths exist in a variety of states; some well preserved, others have been recently restored, but many have been completely destroyed or survive only as a few scattered rocks. I would propose a tagging scheme to indicate the current condition of megaliths, something like site_condition=* or megalith_condition=*, with perhaps a descriptive or numerical value attached.
Would be worth investigating how this could be objectively quantified, or what, if any, authoritative sources exist for this information.
Links to other websites
wikipedia=* Link to the Wikipedia article for the site, if it has one.
website=* Link to the official website for the megalith, if it has one.
Cornwall
Dorset
| Name | Type | Rendering | Notes |
|---|---|---|---|
| Stonehenge | Circle | 37118074 37118074 |
Devon
| Name | Type | Rendering | Notes |
|---|---|---|---|
| Kingston Russell Stone Circle | Circle | 425722873 425722873 |
Wiltshire
| Name | Type | Rendering | Notes |
|---|---|---|---|
| Stonehenge | Circle | 37118074 37118074 |
External Links
- Overpass Turbo a rendering of the megalithic sites in Britain following the above schema