Lost in Spaces: Updates on Writing

There isn’t a lot to report. I’m in the processes of writing (my first draft of manuscript thesis chapter). There was a little shuffling since our last meeting because I reworked the outline of my manuscript.

  • Introduction (last week/done)
  • Methods (this week/in progress)
  • Results (next week/results in progress)
  • Conclusions (First week of May)

That puts me about a week behind when I had reported to finish last time. That said, I was leaving a week to prepare for Titan meeting so there was wiggle room. I’m on track now, but I do fear a slight lag of ~1/2 week.

For next week, there a couple results I’m still working on.  The first is more tedious than anything. We have 30 new craters that’ll look pretty much like Figure (1). It’ll look like this, but I’ll be making some changes. First, I’ll move the figure from word to Photoshop (to maximize image quality). Then there will be some shifting of the crater images and the labels within it. I’m thinking names/labels in top left of each square with certainty at the top right. Before that, I’ll reorder them to be from largest to smallest (in diameter). Right now, they are biggest to smallest, but they are separated into my and Catherine’s crater findings. This will probably take a few hours but hopefully not more than that.

Figure 1: 30 New craters found on Titan. Certainty from 1 to 4 (1 being certain 4 being possible). Image is being edited and improved.

After that, the next biggest change I need to complete is to measure the depths of craters relative to the average depths of the local topography (Figure 2). There are two ways of doing this, (1) arbitrarily assigning some height by eyeballing it, or (2) take an average on either side of the crater. I’ll be doing the 2nd unless otherwise told otherwise.
This won’t be too difficult. I’ve already got the main code done. What I need to do is make some tweaks. First, I need to change the part of data I pull to extend further outside the crater. You can see in Figure 2 that the topography doesn’t extend to the same width of the RADAR image we use to visualize the crater (~3x that of crater D). I’m thinking using somewhere between 100km and 200km on either side. Hopefully, we have enough data and that does a good job averaging. It’ll be easier to define a set difference than assigning a length (which may be needed due to possible anomalies in local topography). If it is that simple, then it won’t be hard to process all 15 craters again (Figure 3) because the hardest part is assigning boundaries (which are hard to find in the more obscure craters) to search for the rim which I have saved (in an excel doc) for the craters I’ve already done. That also defines the crater floor, so all necessary steps will be done.

Figure (2): The topography profile that goes through the center of Selk crater (80km), plotted along the same longitudinal axis as the RADAR image. The depth (d) is measured (blue dashed line) by measuring the distance from the upper most rim position and the lowest floor position (black circle) on the left and right of the crater, then averaged. The depth is again measured (dL) by subtracting from a localized average topography on either side (green dotted line).


I’ll be updating the comparative plot between Ganymede and Titan (Figure 3) with stereo data and using the local topography to find the depths. The plot is easy, the hardest (but still easy) part will be finding the depths from the local topography of Ganymede, but that just uses the rim heights so it shouldn’t be too bad.

Figure 3: The depths of Ganymede’s craters as measured by Bray et al. (2012) (black diamonds) and Schenk (2002) (black dashed line). Compared to Titan’s craters using SARTopo data (red circles), and eventually stereo data (blue x’s). Then I’ll plot the depths measured from the rim height and depths measured from the local topography in separate plots.


I think this is manageable in a day. Worst case, it’ll take two days (Monday and Tuesday). I’ll be grading Monday, so hopefully whatever extra time I have left after grading will be enough on top of Tuesday. Next week really is the big decider on if I’ll stay on track, but seeing as I need this for the Titan Surface Meeting (May 8th) I’m pretty confident I won’t be going too off track. I guess we will see!



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