Data visualisation

Spatial data

The Norse World resource makes use of interactive visualisation of a large spatial dataset. The visualisation itself has absolutely no ambition to represent a historically correct worldview of medieval Scandinavians. Rather, it serves as a method of managing and getting an overview of large amounts of geocoded data (Petrulevich et al., (ms.), see 'References'). Researchers exploring the data via the Norse World interactive map thus should be aware of both the possibilities and the limitations of the visualisation techniques utilised by the resource. For more information, see below and under 'Critical visualisation'. 

Choice of coordinates

The data, or more precisely standard forms, see 'Data and related metadata: spatial references and spatial data', have been geocoded using standard open-source geographical databases and gazetteers such as Geonames and iDAI, as well as the Wikipedia's service GeoHack. Geonames comprises geospatial data mainly on present-day natural features, political and other entities such as countries, cities etc., as well as some features that have ceased to exist, e.g. Ancient Corinth. iDAI.gazetteer contains geodata associated with pre-historical sites, objects and other material from different periods of antiquity in the databases of the German Archaeological Institute (DAI). GeoHack is a service that links Wikipedia articles to a variety of mapping sources containing spatial data. In those cases where Geonames lacks geodata on certain locations we employ the data from iDAI.gazetteer. When the geodata are not available on both of the mentioned gazetteers we take the geodata from GeoHack. Furthermore, each identifiable place name is provided with a stable link to spatial data (including latitude and longitude), a geodata link, taken from GeonamesiDAI, or GeoHack

The rationale behind the gazetteer choice is that there are simply no gazetteers with a pre-medieval and medieval focus large enough to accommodate the project’s needs covering all the places outside Sweden and Denmark mentioned in the East Norse medieval literary texts. For instance, the Pelagios Project exclusively devoted to historical places is incorporating more and more medieval material, but unfortunately its scope is still insufficient. For this reason, the coordinates of modern-day (political) entities have often been used, such as France for Old Swedish Frankarike (Frankish Empire, Kingdom of France) (Petrulevich et al., (ms.), see 'References').

Mapping

Digital maps as both a research tool and as a way of thinking about materials has become of increasing importance in recent years, not least because of the relative ease with which scholars now can make use of geographic information (GIS) technology. Mapping allows us to group the geocoded data in the East Norse corpus as we wish (by date, genre, language, etc.) and visualise them: complex information is distilled down to a visual argument that can be shaped and defined as the researcher needs (Wrisley 2014).

Using the Leaflet library and the Leaflet.markercluster plugin the project utilises interactive GIS to map the geocoded attestation data. The focus lies on quantitative aspects of the data, i.e. how frequently localities are mentioned in the corpus. The employed clustering technique can be utilised as an analytical tool to facilitate comparisons of data distribution in different types of material. The end-user can explore the resource interactively e.g. by using the search function and a number of filters or just by moving around, zooming in and out the map, and clicking on clusters (Petrulevich et al., (ms.), see 'References'). For more information, see 'How to use Norse World' and 'Critical visualisation'.

Basemaps

At the moment, the Norse World resource offers two basemaps taken from open-source map databases:

  • Positron map taken from CartoDB that includes borders of modern political entities. This map serves as a default basemap.
  • Water color map taken from Stamen Design featuring outlines of the continents and other landmasses as well as the World Ocean.

The maps were chosen to clearly state that the visualisation techniques employed by the Norse World resource in many ways are anachronistic and do not represent a historically correct worldview of medieval Scandinavians. For more information, see 'Critical visualisation'.  

Visualisation via the show as field

If a spatial reference lacks coordinates for some reason (e.g. because it is a fictional or an unidentified biblical spatial reference) it can still be visualised via the Show as field. Show as includes information on the geographical entity that the spatial reference in question is assumed to be a part of. It thus reflects geographical contextualisation of the spatial reference in the East Norse corpus. For example, all biblical places (in the Middle East) that lack generally accepted identification and coordinates are visualised as located in the Middle East. Another example is the visualisation of non-names linked to geographical localities, e.g. inhabitant designations. Thus, the inhabitant designation Russian has a show as value 'Russia' for visualisation purposes.

Further customisation of visualisation in offline uses

The Norse World dataset is compatible with offline open-source GIS applications e.g. QGIS. It is thus possible to download a filtered attestation dataset or all the attestations, see 'Exporting the data', to continue working on further customisation. For example, it is possible to improve the visualisation of the dataset by adding other types of spatial data, polygons, and lines, to the dot data that is a default in the Norse World visualisation. As with other software GIS systems, QGIS enables users to create maps with many layers and assemble them in different formats and for different uses.