1. Navigating and Visualizing Archaeological
Data on Vastly Different Scales
Introduction
Archaeological research can focus on scales ranging from
observations on individual objects to macro phenomena that
span millennia and continents. Such scalar differences pose a
great challenge in digital data dissemination, particularly in
finding and visualizing relevant data.
Until recently, Open Context (http://opencontext.org) mainly
managed site-specific data. But the Digital Index of North
American Archaeology (DINAA) project requires Open Context
to manage site file data spanning large regions and time periods.
To meet this need, Open Context implemented data indexing
strategies to hierarchically nest time-span and geographic
coordinates.
The approach presented here simplifies interface, visualization,
and interoperability with Open Context. The nested indexing
strategy demonstrated here enables visualization and discovery
at a level of spatial resolution that does not compromise site
location security, but is useful for map visualization of multiple
dimensions of data.
Indexing with “Time-Tiles”
Eric C. Kansa1, Stephen Yerka2,
Sarah W. Kansa3 , David G. Anderson2,
Carl DeMuth4, Joshua Wells4
• Web mapping services(Google, Bing, etc.) provide base
maps indexed by tiles. Tiling is a widely adopted way to
indentify geospatial resources.
• Latitude / Longitude (WGS-84) coordinates can be
expressed as a hierarchically-encoded string:
37.861844, -122.289677  02301021220232231101
• A nearby coordinate will have a slightly different tile.
But note how the left-most characters are the same:
37.861234, -122.276540  02301021220233220031
• Tiles can be easily aggregated at different scales by
lumping together characters of the same value from left
to right.
• Tile strings can be easily converted into map polygons at
any scale for visualization of spatially aggregated data.
• The DINAA project protects site location data by
converting coordinates to tiles limited to 11 characters in
length. This corresponds to location accuracy with
~15km to ~ 20km.
Indexing with Map-Tiles
Further Information
To learn more about DINAA, visit the project blog at:
http://ux.opencontext.org/blog/archaeology-site-data/
Rough Cilicia Survey (N. Rauh)
• Roman era tomb distribution
• Small-scale regional data
Time ranges can be hard to present in hierarchic faceted search (a standard way to present complex metadata
for point-and-click navigation) since ranges do not usually fit into standard buckets. To solve this problem,
Open Context will start to organize time-spans using a hierarchy of “tiles,” similar to the map tiles above.
1M-00000000122000110221
(Roman: 2000 – 1470 BP)
1M-01001322312033201102
(Middle Paleolithic: 300KYA – 30KYA)
1M-00000000312010332212
(Iron Age: 3100 – 2500 BP)
• Need to define earliest and latest possible dates for a tiling grid
• Latest is 0 BP, example below is 1 Million BP (Open Context
allows 10MYA).
• Recursive function to compute tile from earliest and latest BP date
as input. (Source code: https://github.com/ekansa/open-context-
code)
• Tiles can be converted back to earliest and latest dates.
• Like map-tiles above, time-tiles easily aggregate at different scales
by lumping together characters of the same value from left to
right. Shaded regions show different aggregations of time-tiles.
• Tiles allow arbitrary time ranges to be used in faceted search.
• Time-tiles can be combined with controlled vocabulary of named
periods (in development with DINAA).
Florida Site Files (DINAA)
• Shell midden distribution
• Large-scale region
DINAA: 270K+ State Site Files
• Unfiltered as of March 31
• Highest tile resolution shown
for site location security
DINAA: 270K+ State Site Files
• Also heat-maps etc.
• Lower resolution tile
aggregation
1. Open Context (http://opencontext.org) & UC, Berkeley (D-Lab)
2. University of Tennessee, Knoxville
3. Alexandria Archive Institute (http://alexandriaarchive.org)
4. Indiana University, South Bend
Acknowledgments
DINAA is multi-institutional collaboration
funded by a grant from the National Science
Foundation Archaeology program.
EOL Computational Data Challenge
• Percentage of pig bones at sites
• Areas represent numbers of bones in different
time-ranges in Anatolia
Open Context has additional financial support from the
National Endowment for the Humanities and other sources.
The California Digital Library archives Open Context data.