Topography maps for drainage, Part 1

Recently I’ve been looking at elevation data collected from our Trimble FMX GPS system we use in our tractor.

I imported the logs from this years planting operation. We plant on a swath width of 12m so the data resolution is quite good. The data logs are then transformed into a digital elevation model or DEM and then interpolated to create smoother surface. From the DEM, so far I have developed a contour map and an exaggerated 3 dimensional surface.

Exaggerated 3D surface – note that it is twisted 90 degrees to the below contour map. You are looking from the western side of the paddock.
Contours 20cm

You may have noticed from these diagrams that this paddock has quite interesting topography. A couple of places in this paddock water fails to drain freely which can sometimes lead to water logging. My next step is to identify these sinks.

Software used is the freely available QGIS with GRASS & SAGA extensions available at http://qgis.org.