Godlike Powers....

A few weeks ago as part of our module 'Geomatics of the Coastal Zone', we were set an assignment to model the flooding of the village of Arundel. Slightly morbid... but also brilliant. I much prefer doing coursework with practical applications - 'real' stuff that you can imagine yourself needing to do in the future for a job or research project. To get us going we were given a 1 kilometre square set of Light Detection and Ranging (LiDAR) data - which essentially is a set of points with defined coordinates - which crucially include height data. Here's an example of LiDAR data when viewed in 3D - you can see how it creates a surface when colours are used to represent different heights:

So using this, we calculated the height of the river running through the middle of the village (with some difficulty as the LiDAR data we had didn't return any readings from the river, only bathymetric LiDAR does this), and then started to look at what would happen as the height of the river rose metre-on-metre.

The results when graphed looked like the below, which shows water height above the average river height, which was about 1 metre. The colours change from red to blue as the rivers flood defences break!

It's also possible to visualise the flooding using ArcGIS and data from the Ordnance Survey. The below images show the water 2 metres above the river height, and then 5 metres. Notice the flood defences on either side of the river in the first image - meaning that much of the water shown wouldn't actually have reached that area, but then with the 5 metres image it certainly would have done!

So anyway, that's what I've been doing for the last week or so... flooding Arundel. There are quite a few issues with the way that this has been done, such as the calculation of the river height, and the LiDAR data being quite old, but it gives a good demonstration of how LiDAR data can be used in ArcGIS to model different situations.