I had to prepare a couple of images this last weekend for an abstract for the London Geological Society Meeting in December and in the process came up with the first stab at digitizing some interpretations to one of the many timeslices from the 500 MHz GPR data collected last June. (More information on the survey can be found in a previous post) Initially I wasn’t very keen on attempting interpreting the slice as we still have not corrected the data for topography or tilt yet, but in the end I think it was a good exercise for me in coming to terms with actually making interpretations on the data- versus simply digitizing every reflection on the timeslice. I think there’s certainly some promising anomalies/features appearing in this particular slice (thus far estimated at 85cm below ground surface, but still a contentious estimate).
In addition to topographic correction and velocity analysis, there still needs to be quite a bit of mosaic correction done as well. As the survey was completed over the course of an afternoon and the following morning the relative amplitude ranges as well as the time zero points vary significantly between the two days. For the initial timeslices I ended up correcting the relative amplitudes through various attempts at adjusting the gain curves on each trace, automating and clipping each radargram to their respective time zero point, and then crudely adjusting the resulting amplitude ranges in the pixel based timeslices themselves. I think with greater refinement to the relative gain curves I can probably avoid the pixel based mosaic corrections, but have yet to have the time (and access to the software) to have a real play with the data. Soon enough though- as the goal is now to make some real progress in preparation for the poster in December. Here’s hoping!