Maps of Wales with slope arrows


09 Oct 2015 - MawKernewek

Here are a couple of maps of Aberystwyth, and Cadair Idris, with the RSGISlib segmented digital elevation model.
Slope direction is shown by arrows, and coloured in the same scheme as previously with thicker arrows for steeper slopes, and longitudinal curvature indicated with convex slopes red and concave blue.

1:10000 seems about the limit of the smallest scale that QGIS will cope with the arrowed lines. Beyond that the computer just hangs - slope lines without arrows can be plotted without problem.

Aberystwyth town centre, and the university campus. full-res version

Cadair Idris. This is a textbook example of a glacial landscape in the British Isles. full-res version
Aberystwyth area and Rheidol Valley. full-res version

Dyfi Estuary showing Borth, Tywyn and Machynlleth. full-res version
To readers: are there any requests of areas you would like to see?

The processed data currently includes the following area though I also have the whole of British Isles (except most of Shetland) DEM from 1 arcsec SRTM (and could download anywhere up to 60° latitude) but not processed to create slope curvature layers and segmented.

Pen-y-fan area, Brecon Beacons

Pen-y-fan main summit to the right of centre, showing the slopes convex at the top, but generally concave further down. full-res version
Broader context at 1:40000. full-res version

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