Digital river mapping

One of the main outputs of the Visualising Geomorphology Working Group was the commentary by Tooth and others (2016). In this commentary, we pondered whether newer, technology-driven artistic approaches could be employed to communicate geomorphology to non-specialist audiences, noting that geomorphological subject matter had yet to feature widely among a recent surge in digital artworks.

Work by digital cartographer Robert Szucs illustrates some of the many possibilities that exist. Under his monikor GrasshopperGeography, Szucs uses open-source geographic information system software to map the world’s rivers. The resulting maps are striking visual displays of river networks on the various continents, and have been picked up widely by various media outlets and websites (to illustrate this variety, see CNN Travel, The Daily Mail (online), and IFLScience!).

Szucs says that the maps are “100% scientific” as they are based on satellite data and digital elevation models, and with every river being placed on a scale of 1-10 according to the Strahler stream order classification (in most settings, stream order is a rough proxy for size). The map designs, however, involve many artistic decisions, especially the choice of line widths and colour combinations. Each map commonly goes through many iterations over days and weeks before the final output is realised. And although the impression of space filling by river flow could be slightly misleading – the line widths obviously cannot be scaled in accordance with the actual map dimensions and the networks don’t reflect the permanency or otherwise of flow – the maps nonetheless illustrate graphically the potential importance of river action.

Map of Australian river networks, with adjacent catchments coloured differently. While most of the river networks form tree-like (dendritic) patterns, the parallel patterns in the centre of the continent reflect the influence of the southeast-northwest aligned linear dunes of the Simpson Desert in controlling the flood flows that periodically occur along the various rivers entering from the northwest and north. [Nb. Here the ‘mapping’ goes a little awry I think, for as ones goes farther and farther southeast into the Simpson dunefields, there really is no coherent surface drainage, so as mapped, the rivers are too long.] [Image provided courtesy of].
For me, Szucs’s work is an interesting example of how science data and digital art can collide in creative ways and highlights the great potential for communication in outreach contexts. The maps are visually arresting and may provoke questions about what the maps actually mean. Why are there so many river networks on the continents?  Why do they typically form tree-like (dendritic) patterns with their roots in the oceans?  Why does the centre of the Australian continent appear to be such a weird exception (see image above)?  These are not necessarily easy questions to answer but perhaps medical analogies could help. For instance, if ones sees mountain ranges as the skeleton of a continent, then could these maps be used to suggest that river networks are effectively the arteries, conveying water, sediment and nutrients from the continental interior (the ‘heart’) to other parts of the landmass (the ‘body’)?

[Posted by Stephen Tooth, December 2017]

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