W3G conference: Geodata at the British Museum
33
description
Transcript of W3G conference: Geodata at the British Museum
Portable Antiquities Scheme
• 17,900 contributors of data
• 640,000 objects recorded• 400,000 geo-referenced
find spots• All available under CC
NC-BY-SA• Driving archaeological
knowledge of rural areas• Funded by DCMS
• Employ 56 people• Deal with public
discovery of archaeology
• Started in 1997• Costs £1.4mill per
annum• IT budget c.£5000
Recording: one chance
Our staff generally have one chance to record Dissemination online is swift, cheap, easy There is no other archaeological database of this size It is underused for research at present The data it contains can tell a thousand stories of our shared heritage
Objects by year
449,359 objects online @ 23:20 26/2/10 – 400K in 7 years!
Most data is sourced from metal-detecting
GPS co-ordinates if possible
All objects recorded online
The Staffordshire Hoard
Frome (Somerset) Hoard
Crosby Garrett (Lancashire) Helmet
A more normal discovery
Objects referencing place:The Staffordshire Moorlands trulla
This is a list of four forts located at the western end of Hadrian's Wall; Bowness (MAIS), Drumburgh (COGGABATA), Stanwix (UXELODUNUM) and Castlesteads (CAMMOGLANNA). it incorporates the name of an individual, AELIUS DRACO and a further place-name, RIGOREVALI.
http://www.finds.org.uk/database/artefacts/record/id/49791
Have you noticed a pattern?
Big discoveries named after place…Place => sense of identity
Why is the spatial data so important?
Without provenance: A museum cannot acquire an object Is it looted? Did the landowner give permission? Context has been lost, we don’t know the significance of the location of discovery.
"X" never, ever marks the spot.
Indiana Jones: Last Crusade
All objects we have recorded
• 1997 – 2010• Topographical features drive
discovery• Landowners and regulations
can prevent discovery• Biases present in data
collection eg. Staff illness, lack of car etc etc
Staff based here
Here be mountains
Using YQL
• Reverse geocode for WOEID for each findspot against flickr.places
• Get flickr shapefile if exists for WOEID• Obtain a co-ordinate for findspots where only place
is known (lower weight for academic use though).• Obtain elevation via the geonames api (for
viewshed analysis – surprisingly good!)• Find objects within bounding boxes• Query for archaeology images on flickr
Problems
• Hit rate limit quickly – now using Oauth calls to Yahoo apis
• Had to filter out places eg Copper Alloy, Tamil Nadu was constantly pulled out with Placemaker
• Took time to process 400,000 records for geodata
Display problems
• Public users can only see find spots at a resolution of 1km sq or 4 figure NGR
• Some find spots have to be hidden from public view completely – we give a place a pseudonym
• Maps make our finders and landowners jumpy• Zoom level had to be reduced for public users• WOEID can give away find location
Enhanced geo data via flickr shapefiles & Yahoo! geoplanet
This object only has a known place of discovery
So Yahoo! does legwork and produces geodata
Integration of old OS Maps
Layer provided by National Library of Scotland
Water Newton (Cambs) rally
Roman town of Durobrivae
Re-use of OS and EH point data
Both of these datasets came as CSV, now converted from grid refs to Lat/Lng and WOEID (and also elevation for centre point) if anyone wants them.
Data export
• All searches can be turned into KML/JSON/CSV/XML (however point data degraded to 1km square unless higher level user)
• Can be easily imported into Google maps for instance
• One example is a search for objects by Parliamentary constituency (powered by YQL on theyworkforyou and Haversine formula)
Simple YQL query: select * from twfy.getGeometry where name=‘Stratford-on-Avon’;
Powered by theyworkforyou api
<results> <twfy> <max_e>436973.6</max_e> <centre_lat>52.168328098</centre_lat> <area>670735121.325</area> <max_n>274456.4</max_n> <min_lat>51.9553938864</min_lat> <max_lat>52.3680842693</max_lat> <min_n>228616</min_n> <max_lon>-1.46139563588</max_lon> <centre_lon>-1.71287824875</centre_lon> <centre_n>252253.483284</centre_n> <parts>1</parts> <min_e>402695.3</min_e> <centre_e>419756.726723</centre_e> <min_lon>-1.96200666642</min_lon> <name>Stratford-on-Avon</name> </twfy> </results>
Objects in David Cameron’s constituency
What archaeologists would like: A database of places – ancient & modern?
• Ancient place names– Dates in use– Co-ordinates at that time– Affiliation (political)– Example database – Pleiades, NYU
http://pleiades.stoa.org/• Modern place names
