the giCentre, Department of Information Science, City University London,, EC1V 0HB, United Kingdom
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Has geomorphometry really changed in the last 30 years? As someone who mainly
researches in the field of information visualization and GI Science, I ask myself this
question whenever my research takes me back into the realm of digital elevation model
analysis where I started my career 20 years ago.
In the 1970s Ian Evans was proposing the use of quadratic interpolation of DEMs for
the systematic measurement of the first and second derivatives of elevation for general
geomorphometry (Evans, 1972, 1979, 1980). Modern geomorphometry still uses the
techniques and approaches he proposed for slope and curvature measurements over 30
years later. At about the same time David Mark was advocating the systematic use of
gridded elevation models and computer based parameterisation of those models as the
bases for geomorphometric analysis (Mark, 1975a,b). Again, this forms the basis for
modern geomorphometry, albeit with larger DEMs at finer resolutions.
It can be argued that modern hydrological geomorphometry is equally based on the
approaches established in the 1980s, such as flow accumulation, channel delineation
and watershed partition (e.g. Jenson, 1985; Band 1986; Hutchinson, 1989). Little
appears to have changed since then other than the use larger datasets or minor
modifications to algorithms such as moving from D8 to D∞ flow models.
Reviewing Hengl and Reuter’s text Geomorphometry: Concepts, Software and
Applications (2008), it is clear that one aspect of geomorphometry has changed in the
last 30 years or so, almost beyond recognition. The visual presentation of
geomorphometric analysis has evolved from monochrome low resolution overplotting
of line printer output to multi-megapixel full colour output. Yet if we think of
graphical output as solely a mechanism for presentation, geomorphometry will fail to
exploit the true power of recent development in visualization.
In parallel with the development of graphical techniques has been the emergence of
information visualisation and visual analytics – research disciplines that focus on the
use of graphics as an intrinsic part of the data analysis process. The speed at which
graphical output can be created, along with graphical interaction means that
visualization of data can be used as part of the analytical process, feeding back to the
way we handle our data and draw conclusions from it. This paper will argue how we
can learn from the developments in information visualization and visual analytics in
order to enhance the way in which we undertake geomorphometry.