Date: Monday, 06 December 2021
 

Monitoring Team: 
 

Analysis & Report: David Bills-Thompson, PFCG Technical Officer and Data Co-ordinator

 

Commentary: 

The PDF files show the transverse profiles at all of the posts with separate profiles for the beach (in front of the post ) and for the dune behind the post except for post 4 which has a strong secondary dune in front protecting the main dune and hence no need for a rear profile at this time.

On the charts there is a new feature used to validate drone mapping measurements.
The red diamond on the "zero" post axis is the validation check for the drone profile at the post and is derived from a direct physical measurement of the length of the post at the time of mapping. Special thanks to Nick for his measurements during the last mapping on 6/12/2021.

The way the validation works is that the thin red profile line calculated from drone images should emanate from the centre of the red diamond for a perfect validation.
ie. The measured sand elevation at the post equals or is close to the calculated elevation from drone images. When these values are not equal, the chart legend lists the difference in elevation between the measured value and the calculated value. (Showing the validation detail in the chart legend carries the validation data with the chart when it is copied from the spreadsheet and embedded in a separate report).
The limit value for validation determines the detail in the error message displayed in the spreadsheet and is adjustable in the Control Panel.

It should be noted that where a post is located in a secondary dune with vegetation and undulating surface, validation readings are less closely matched than in other areas.

Due to the volume of material available from drone mapping, results between the Parks Victoria car park and Mills Reef have not yet been analysed. I will issue these as soon as possible along with the updated spreadsheet that includes the new validation process.

 

​