Foto: Werner Karrasch; © Vikingeskibsmuseet.

GIS and mapping

Geographic information systems (GIS) are computer programmes designed for mapping and the analysis of geodata; i.e. data that can be linked to particular positions. In this exercise you will use GIS to analyse The Sea Stallion’s observations from the voyage to Dublin. There are several free GIS programmes available on the Internet.

  • Import the voyage data into your GIS. Map the voyage (you may need to adjust the length and width of the column to a format which your GIS can work with). You could find and download a suitable free background map from the Internet.
  • Find and remove erroneous data. (Tip: Search for impossible values; for example course>360º or width>90º.) Note that it may not be the whole record which is erroneous. For example, the anemometer may have malfunctioned without there necessarily being errors in the other measurements. (This can of course be done in another programme before being imported to the GIS.)
  • You can also choose to remove records from when the ship has lain stationary in harbour.
  • Make thematic maps with the various recorded data as the variable. For example, a map that uses colour to show the ship’s speed. You may need to remove records where the instrument in question was malfunctioning.
  • Look at the trace of the ship. Are there places where there are unexpected changes in course and/or speed? What could be the reason(s) for this? (Tip: Look in the logbooks and diaries and see what happened on board at that particular time.)
  • Use GIS in solving the exercises maximum speed, rowing, tacking abilities, turns and the speed diagram. Does it provide new opportunities for displaying the results?

 

A series of exercises has been produced which aim to analyse The Sea Stallion’s handling abilities under sail and oar power respectively. In other words, the pupil is able to carry out him- or herself much of the research which the Viking Ship Museum is to embark upon after the voyage to Dublin. The exercises are best tackled in the order shown, and it is a good idea to present the results together in a final report.

The data set to be processed comprises the ship’s geographic co-ordinates (recorded with the aid of a GPS) as well as a series of other navigational and meteorological measurements. All of this is assembled in a zipped, semicolon separated text file Datalogger which can be downloaded from Tools in the right hand column of the exercise. This table can be used as the basis for a large number of exercises involving data validation, source criticism, searching and sorting, calculations and column updates and much more. The exercises are best executed with the aid of a spreadsheet and/or GIS and can be incorporated in a wider teaching context dealing with, for example, the GPS system, statistics and cartography.

GIS and mapping is an introduction to solving the other exercises with the aid of GIS but also leads up to the production of thematic maps and other analyses of the recorded metric data. You could query GPS and the surveillance society against the background of the information about and interpretations of the events on board which it is possible to deduce from the GPS trace.

Subjects: Maths, physics, geography, general study.

Level: Sixth form/A level.