TERRAIN MAPPING
Using an off-the-shelf drone for Flood Management
Combined with the right software, drone imagery can be used to generate a Digital Surface Model (DSM) – this is a 3D model that shows terrain elevation. It can be a very useful tool when looking at flood management and defence on your farm.
In this example, we use the data to calculate the size and location needed for a flood barrier that is being built to protect farm sheds.
1. Map the area
Using Dronedeploy
We use the software to plan our flight to cover the whole area, taking lots of photos for a high coverage. This took about 15 minutes to cover our farm flood basin.
2. Process Data
to Generate 3D Model
Once the data is collected, it is uploaded for processing. The data will then be available as a standard map, elavtion model and 3 model of the area.
3. Access elevation toolbox
to Identify Areas at Risk
The toolbox is used to show areas of low elevation which are likely to flood, knowledge of past floods helps to place a base height marker on the map where flood water has not risen to in the past.
The markers give a height measurement which are accurate to within centimeters relative to other points on the same map. Once a point is identified where flood water normally gets to, other markers are added where the flood barrier is to be located. an elevation offset can then be calculated, giving the required height of the barrier at various points. Length is also measured. Data is then exported as a PDF report for the JCB operator.
4. Re-map area
After Construction Complete
Once the barrier construction is complete, we re-map the area and generate another 3d model and elevation maps in order to check the barrier meets the requirements.
5. Measure barrier height
for Final Report
The elevation toolbox was used again to drop markers on the now complete flood barrier and compare height values with the base safe heights at 0 m (points 4 and 5 in the report).
We found that while each end of the barrier was only 10cm below the requirement, the mid point (number 2) was 0.7 m lower than needed, and required more material to get it up to the required height.
Barrier earth volume can also be calculated and used as a reference for similar future projects.
More information and links
You can view and have a play with the final live version via the link below.
We used the Mavic Agri Pro drone system to fly each map in about 10-15mins. Processing took 24 hours after uploading to the internet.
If you want to learn how to do this with your drone, and a lot more useful applications for your drone on the farm, try our new training course.
