A Digital Elevation Model (DEM) is a data set containing information about a terrains surface. In its most basic form it is a collection of geographical positions with associated elevation information. With this information it is possible to make visualizations or calculations which again can be used to understand how objects on the surface can interact.
As a geographer it is most of the time my job to facilitate for the use of spatial data. Working with elevation data is as fun as it gets, technically. The data sets lends themselves to nice visualizations and given the right questions the data sets might tell us interesting things about the relations between water, biological entities and masses. The much used watershed analysis results in an understanding of to which rivers water in an area drains. Among other things this is used to understand and manage water basins within the European Union.
For some years now there has been a discussion in Norway about the quality of our current elevation model. Most of us would agree that it could be better. I am one of them. In this posting I will try to give the reader some background to my view on this issue.