Geographical information retrieval – finishing touches
In my last post back in July I wrote about the development of a set of APIs and an interface for geographically querying historical places and their annotations, which allows users to browse a long lost territory and retrieve information about historical artefacts. However, even an application as simple as a map visualisation wouldn’t be possible, if services, data, and tools weren’t made available to the community by a number of different parties. Naming all those upon whose work I have built is no easy thing. But the following have been especially helpful:
- Provinces’ polygons from Depauw University
- Historical tile sets from Regnum Francorum Online (kudos to Johan Åhlfeldt)
- Pelagios API (kudos to Rainer Simon)
- Pleiades project for providing the coordinates of the historical places (kudos to Sein Gillies)
- OpenLayers API
Correction of box annotations
|Grid effect on heat spots|
The effect is quite clear when visiting a province like XI, in Italy, where the spots are seen clearly positioned in an organised grid. Not only. It seems in fact that for regions like these, the majority of the annotations are grouped in this way. Clearly, the presence of numerous annotations like these undermine the purpose of having a heat map in the first place since the information about the original place associated to an annotation is lost and the contribution from the precise annotations is somewhat shadowed.
For this reasons all annotations whose geographical context is not a point has been ruled out as contributors for the final heath map, obtaining as a result a more informative map where hot spots are grouped around historical settlements like in the figure below.
|Heat map without box annotations|
Integration of Historical tile sets
An interesting addition to the interface is the adoption of a particular tile set for historical regions developed by Johan Åhlfeldt in his project Regnum Francorum Online (a description of his work can be read in this blog here). The tile set allows users to provide a background for historical maps which includes names of ancients settlements and depicts also well known roman roads (like the Appian way) alongside known mines and sanctuaries.
Seeing the actual historical landscape with the original names and connections among settlements can only increase the allure of exploring archaeological artifacts and in fact provides the best context in which to put what can be accessed via the different APIs from the Pelagios data galaxy.
This work has been supported by Pelagios and I’d like to thank Leif Isaksen, Elton Barker, Rainer Simon and Johan Åhlfeldt for sharing their ideas, support and resources.
Research fellow WAIS group Electronic and Computer Science University of Southampton