Well its been a little longer than I anticipated updating this page with what I have been working on but rest assured this isn’t due to a lack of activity more a lack of internet at home.
Numerous projects have been going on both on the surface and underground but I thought I would start with some updated data from Ravens Well. For Christmas I treated myself to a small drone (the DJI Mini2) mainly so I could add some surface features to the underground surveys I have been working on though flying it around aimlessly is equally fun !
The learning curve I found to be very easy and by lunch on Christmas day I had produced a model of my house. After a bit more practice and experimentation I was ready to capture the images required to create a surface model of the area above Ravens Well around the three lamps junction of Bristol, ever curious each time I walk/ cycle/ drive over the top as to where the tunnels are exactly beneath this would provide the answer more accurately than just overlaying the underground model/ survey roughly in Google Earth as the Axbridge Caving Group have done.
The flight took about 20 minutes well within the drones ability and Metashape processed the images very efficiently. I used RTK GPS to measure the positions of some prominent features on the ground mainly road marking which were clear and well defined in the point cloud. These were then matched up in CloudCompare resulting in a reasonably accurate surface model of the area. I once again scrambled down to the entrance to the tunnels and to my surprise found that I had fixed RTK status next to the entrance so I marked a temporary point and quickly surveyed from the GPS point to a point marked inside so that the drone data and underground data could be tied to the same reference and overlaid.
Overall a successful addition to projects, easy to do and gives a better understanding of the relationship between above and underground features.
