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.

craters
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.

depths.PNG
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.

titandepths3.19
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.

Continue reading Lost in Spaces: Updates on Writing

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LPSC and a Race to the Finish

LPSC was an amazing experience. The best part was probably being able to experience to interact with people I know (see the cover photo of Kevin, Gavin, Jeff, and me). And, I say that as more than a matter of just socializing (although it was great getting to catch up with Kevin!). Going to this and running into people I know really affected how I perceived my own sense of belonging to the community in a way that changed the entire experience for me. Other than that, I had an oral presentation and I think it went rather well. My favorite session was probably the Pluto session. My first LPSC was brand new Pluto data, and it’s fascinating how much things have changed over the last two years. Of course, I really enjoyed the Titan and Cassini sessions. Although, I was really caught up in my own presentation during those sessions. I haven’t sat down and reviewed my notes, but I should review my thoughts on the things I saw.

With the recent acceptance into Western’s PhD program (yay), there is more pressure to finish writing my master thesis for my defense at the end of the summer to ensure I make it into the PhD program in September. With that in mind, I think an itinerary for the summer is in order.

First up is the month of April.

My focus this month is on the first draft of my manuscript for my thesis and paper. The current outline/plan is as follows:

  • Intro stuff (April 6th) (although I’m not sure if this is necessary if I have a ch1 intro already)
    • Discuss Cassini Data and Titan data and Titan overview (as it relates to impact craters) and a Crater Population overview
    • This is to be done by the end of this week (April 6th). I think the Crater Population overview is the main focus for the week.
  • Crater Population (April 13th)
    • Discuss new craters, the radar imagery and then present a complete tabular data review
    • Discuss the distribution (quantifying spatially) and present updated calculations on surface ages
    • Meet with Catherine, discuss final list and review SARTopo depth data
  • Morphology (April 19th)
    • This involves finalizing sartopo data set (ensuring right rim positions and determine whether all craters used should be used)
    • Gather data for stereo and altimetry (from past sources)
      • compare in depth and diameter and in discussion
    • Each week is planned for Monday-Tuesday writing with Wednesday-Friday free to finalize this topo data and do an analysis of resolution limitations. And that also gives ample time during the rest of the week to catch up if I don’t finish during the first two days of each week.
  • Global Degradation (April 23rd)
    • Depth to Diameter plot and discussion on implications for Titan’s surface
      • easy plot to update with previous week data completed
  • Future Work and Conclusions (April 23rd)
    • Chapter 3?
  • With room to review over weekend and beginning of following week before sending to Catherine for edits.

My May schedule begins to be more hectic and will become more defined as I get a better idea of what my final chapter will be.

My idea of chapter 3 is as follows:

  • Opportunity for future work
    • high-resolution ISS map
    • Dragonfly
    • Landscape evolution modelling
  • Conclusions
    • Summary of crater distribution, morphologies, and the state of Titan’s surface

Really, this is maybe 4 pages of double-spaced work, maybe 5? I don’t really understand how this constitutes a chapter unto itself or how I make it independent.

That said, my May schedule and plan is as follows:

  • May 1-8 prepare updated/final presentation for Titan Surface Meeting*
    • This will be the starting template for master defense presentation
  • Write review opportunities with ISS map and Dragonfly (May 15th)
  • Make any other edits to chapter 1 and crater population of manuscript/ ch2 (May 18th)
  •  Visit Mother May 21-24
    • unlikely to have time to write/edit
  • Visit Dad starting May 25th*
    • Landscape evolution and conclusion (May 28th)
    • Edits to Morphology (May 29th-May 30th)
    • Edits to Global Degradation (May 30th-31st)

Okay, with that outlined, I’ll elaborate on the starred/bolded points. First off, the Titan Surface Meeting is May 9-11. I received notice that I will get my housing and travel covered. I was planning on driving, and I’ll probably be given a room with a local grad student (because I was the only male to receive the travel award and they would have to buy a room for just me). I expect the presentation to be mostly like LPSC with more finalized tabular results, and a depth/diameter plot that compares different topographies with my final take away points listed. This will allow for final comments, suggestions and points for me as I approach my defense.

I’m visiting my mom in mid to late May and do not expect to be free to work those four days. Then I will be visiting my dad right after. I did not initially intend to stay so long. I had to cordinate with my mom, and the timing just made more senses to stay until AbGradCon rather than travel back to london then back to Atlanta (my dad is in Jacksonville). Then I got this huge last second news that my dad is getting married on June 2nd. The timing does work out. My current schedule leaves me with just the final summary of the chapter 3 (may require more work prior to trip if I have underestimated Chapter 3) and edits during the trip. I feel like this schedule is managable, but it is my goal to get the hardest part done BEFORE my trip. Comments and suggestions are welcomed.

For the AbGradCon, I have recieved notice that I will have a poster (impact craters on Titan which I’ll tie to dragonfly and Catherine’s paper in review). I am also getting registration and lodging covered.

I said I could cover flight (and possibly lodging with friends) but they gave me what I hoped for, which was a a comfortable conference expereince. I have registered and made the request for my room (with roommate). The poster, I would rather work on while traveling. I have friends at Tech who can help me get it printed for ~$15 or less on campus. That’s just a lower priority, and I’d like to be able to put that second to revisions and writing.

With that, June becomes a little less hectic than May:

  • AbGradCon June 4th-8th (return morning of the 9th)
  • Ch 1 Edits (if needed) (June 11th)
  • Reedits Ch 2 (June 15th)
  • Edits Ch 3 (June 20th)
  • Science of Early Life (McMaster University) June 24th-June 27th
    • using same poster as AbGradCon
  • Final read through (June 28-29th)

Then July becomes Thesis defense prep

  • Make Presentation July 2-6
  • Edit/Practice Presentation (July 9-13th)
  • Do what July 16-27th?
  • Defend July 30th, 31st?

I know there is more to my defense than presenting it to the public. I need to be prepared to defend it to the committee. Topics to review (to what level?) last couple weeks:

  1. Impact Cratering (9th-11th)
    1. Impact Crater Mapping
    2. Formation Mechanics
    3. Modification (relaxation and erosion)
      1. Landscape Evolution
        1. aeolian (dune processes)
        2. fluvial (rain, river, lake processes)
  2. Icy Moon Structure (Titan vs others) (12th-13th)
    1. tools for defining
    2. implications on impact cratering
    3. differences and comparing
  3. Titan Ionosphere and Atmosphere (and how they interact on a physical level) (16th-18th)
    1. Chemistry review (tholin production…chemical processes)
      1. understanding of early earth atmosphere
    2. Interaction with methane, water, and atmosphere
    3. Implications for life?
  4. Cassini (19th-20th)
    1. Mission life
    2. Instruments
      1. Detailed understanding of radar and making of sartopo (I think I’m still lacking this)

One last thing (summer outreach)

I’m not planning on participating in Fake Space Camp, but I would like to do outreach this summer. Last year I presented twice to the Cronyn Observatory public nights (on Saturdays May-August), and I really enjoyed it. I would like to do that again this year. I have several presentation ideas lined up that will take a little prep work, but will be a fun easy discussion with the public about icy moons, Saturn, Cassini, and astrobiology (i.e. my interests).

I’ve actually got more than ideas, I’ve got an out line for 6 different (sometimes lightly overlapping) presentations. Heres a list of ideas and outlines just because I happened to already have thought about it.

  • A voyage through the solar system (and our place in the solar system)
    1. The sun
    2. Mercury
    3. Venus
    4. Earth and the moon
    5. Mars and its moons
    6. Jupiter
    7. Jupiters moons (galilean)
    8. Saturn
    9. Saturns rings and moons
    10. Uranus and its moons
    11. Neptune and its moons
    12. Pluto nad Charon
    13. Keiper Belt and the Orrt Cloud

This is similar to existing presentations, I would restructure it a bit to make it my own or just use an old one.

  • Life in the solar system
  1. What is life? (and stuff for life)
  2. Life on Earth
  3. Life on Mars
    1. Viking Lander
  4. Europa
  5. Titan
  6. Search for life in the Universe
  7. Kepler mission
  8. SETI
  9. Contact plug

This is a ppt I have from last year.

  • Remembering Cassini (a year later)
  1. History
  2. Launch
  3. Arrival
    1. probe to titan
  4. Life span
    1. Studying Saturn
    2. Visiting Titan and Enceladus
    3. Other Moons and the Rings
  5. End of Mission
    1. Playing iconic end of mission clip from youtube (bring speaker)
  6. Inspirations for future missions
    1. Titan
    2. Enceladus

A new presentation to talk about Cassini and its ending

  • Titan: the most unique moon in the solar system
  1. Location (Saturnian system)
  2. Cassini
  3. previous expectations
  4. Huygens probe findings
  5. Atmosphere
  6. Structure compared to other icy moons
  7. Surface (and processes)
  8. Chemistry and Life
  9. Dragonfly (proposed lander/quadcopter)

Talking about Titan

  • Europa: finding life on an ocean world
  1. Icy moons (an explanation)
  2. Galilean satellites
  3. Tidal forces and liquid ocean
  4. Similarities to Enceladus
  5. Ingredients for life
  6. Europa flyby
  7. Europa Lander
  8. Tests for life
  9. Reality check (on finding life and a Europa Lander)

Talking about Europa

  • Telescopes and satellites: how astronomers study the universe
  1. History lesson
    1. prior to Galileo and Galileo
    2. Galileo to now
  2. Modern Telescopes (amateur astronomy)
  3. Ground Based Telescopes (examples. abilities and limitations)
  4. Space Telescopes (examples, abilities and limitations)
  5. Types of light
    1. explaining what it we are detecting
  6. Rovers, Satellites, and probes
    1. Rovers
    2. Satellites and probes (with examples)
    3. Notable missions
      1. Voyager
      2. Galileo
      3. Cassini
      4. New Horizons, Juno and more

Inspired, I think, by the chapter in the Encyclopedia of the Solar System.

  • Icy moons and Ocean Worlds
  1. Earth
  2. Mars
  3. Icy moons
  4. Ceres and Vesta
  5. Europa
  6. Enceladus
  7. Titan
  8. ??

[see last year ppt; would overlap with titan and europa talks]

 

 

Crater Hunting in HISAR (and writing)

So, I visited home and had a good time visiting friends (and my sister). I played some fun deception games at Deceptacon. Unfortunately, I came back with a bit of a cold, so I ended up working from home during reading week (as a favor to my peers more so than the severity of the cold).

I’ve been writing. The end of the month is here and the first chapter of my master thesis is about to be submitted to Catherine for review and edits. There isn’t much to say about that at the moment.

The other thing I’ve been working on is looking at Titan’s craters again but focused on HISAR images. Past crater searches haven’t focused a lot on HISAR, and we’ve found some interesting features that seem to have gone unnoticed up to now. I won’t try to go through them all here, mostly because I’m running low on media space for my blog. Instead, I will redirect you to a google slide presentation I put together that runs through all the craters I’ve found (not previously known). The first phase of review has already been done, so the list is down to I think 23 craters, and of those ~10 or so are, I believe, completely new from this run through (either that or they weren’t reviewed during the first look through with Catherine).

In this google slide presentation I have made a few notes in slide, but also some in the notes section of each slide (you should be able to add comments to the file if you wish). I think the key features I looked for smooth (dark) circular center with a rougher (brighter) terrain surrounding it in a semi-uniform manner like an ejecta blanket (Figure 1).

crater example
Figure 1: The key features I looked for smooth (dark) circular center (in red) with a rougher (brighter) terrain (in yellow) surrounding it in a semi-uniform manner like an ejecta blanket.

 

Now and Then: Titan’s Crater Editions

So, last time I forgot to talk about all the time I spent over the break working to update the depth to diameter plot for Titan’s craters. This entailed finding the craters that had adequate data then interpreting it. The hard part was needing to go back to the start to extract all the data again because I had not saved error data. Unfortunately, this proved rather difficult to do remotely but I manged to figure it out.

crater depths
Depth to Diameter of Craters on Titan (in progress)

These last couple weeks I’ve spent finishing up my list of craters. Or maybe that’s not a great way to put it. I went through and I found each crater and matched it with the previous crater list. Now, this entailed reanalyzing craters by deleting, resizing, and in some cases adding to the total map. In total, there are a 111 craters including all of my craters and those on the list already, but 13 I’d consider 13 of those as not craters.  Needless to say, this process was tedious, especially since GIS doesn’t recognize the projection properly.
After that, I had to identify which swaths (stretches of images) are available for each crater. My computer is not equipped at handling large amounts of files in GIS. So after several failed attempts of making it work, I ended up using 32ppd projections (compared to 128 mosaic res). Except, I had to insert them one at a time, and study them mostly individually. In the process, I noted which craters it covered. I made note of each one that covered it and I marked coverage in 64ppd (lowest used) with a star*. I also rated each swath on a scale from 1 to 10 (bad to good) for the quality of each imager because not every swath turns out as a well as others (even on the same resolution). Now, this may sound easy, but made I felt like I was going bad doing one, after the other, after the other. I then converted these numbers to letters A through J, and to prevent the lowest resolution swaths from overlying decent quality higher resolution swaths, I labeled them such that the highest quality 64ppd swaths would only make it on top of a given layer of 128ppd (~5/10).

tt
Final Titan Map

 

The result is mostly the same, with some changes. One big change is that one image moves for the north middle to south west (not sure what did this), and some high quality swaths overlap other good swaths that don’t blend as well. But its not as if I can import thse into photoshop and overlay them individually (I mean I can but thats not viable).

The ordering took a long time, but so did mosaiking, but while it was going I worked to update the code. Now each crater gets its exact name (in the existing crater list) and lists its diameter in the literature and that I found. Then it plots each. If SARtopo data is available it is used and the plot uses red dashed lines instead of red lines.
As I right this, the only thing I haven’t achieved yet is that I want to get my code to plot the 13 craters I didn’t plot to see what they look like so I can compare those to previous literature. Hopefully, I will have that ready for my meeting with Catherine tomorrow 🙂 . I am also finding that may images have black regions, where the data is saturated out for some reason. I suspect this is a problem with my code because its having trouble processing such a large image and instead messes up in places. I don’t think I’ll be able to fix this in time, much to my chagrin.

#5 Sinlap 12N016
Note, New (red)/Old (yellow) diameters, but new does not reflect SAR data. (to be fixed)

note any final issues, but mostly see how they’ve changed and how they map in ISS. The reason we see these black spots in the first 4 images is because, even though they include different base resolutions, the project resolution (128ppd) is the same.
One glaring issue with the ISS data is that they rarely match up. I don’t know if I’ve got the wrong coordinates for the ISS (assuming the extent is -90 to 90 in y and 360 to 0 in x).For now, that’s all I’ve got with the possibility of updates before meeting.

UPDATE: Black spots have been removed. I recycle codes and sometimes things get left in. Other times, I do things that seem to make sense then seem like nonsense later on. Either way, it was a problem where I was zeroing out the highest (brightest) points.

 

 

A new year.

Its been a busy start back this year. I got back a couple weeks ago, but friends wanted to go skiing, and I figured I couldn’t pass up skiing at least once while in Canada, and I loved it. It was a lot of fun. I also feel like I improved a lot (which isn’t hard as I had no idea what I was doing).

But not long after getting back, I had to prepare for the Gordon Research Conference on the Origins of Life. But before that, I got to go to a friends wedding in Philly. It was my first time there so it was an amazing experience getting to explore one of the most historic parts of America along with a number of museums (including the Franklin Institute as seen in the cover photo to this post). All in all it was a great experience, and the wedding was awesome and a lot of fun.

I missed the first couple sessions of the conference, which was disappointing, but I quickly got into the swing of things. Needless to say, this isn’t my field of expertise, and this is a very specific field. That said, it is closely related to the field of astrobiology, so I recognize how important it is. It’s also just one of the most interesting scientific endeavors going on today. It was a very informative and fun experience. Although I struggled to follow along a lot of the time, I feel like I left with a better understanding of the field and with a better appreciation for some of what I thought I already knew.

I would have to say the best part for learning was the poster session. I didn’t get to look at as many posters as I would have liked, but the few that I did get to see helped me understand, at the least, the basic principles better. I could probably tell you what most of them did but only because I was able to discuss it with the presenter in detail. The poster session was great for more than just this. It was a great way to meet and network with people in the field.

That leads me to probably the best part of the meeting. It was by no means the smallest meeting I’ve ever been to, but the way the meeting was set up made it a great opportunity for networking. From the communal breakfast, lunch and dinners to the poster session and end of day social. Eating with everyone made it hard not to force yourself into a situation where at the very least its only polite to talk. Then over time I got more comfortable and became more talkative (it also helped after Catherine wasn’t there to sit and talk with 🙂 ). I think it was Tuesday when I found out that there even was a social where we snacked, drank and talked. By thursday night, most of the grad students where all together in the lobby playing Cards against humanity. I found out that there was a large population of Ga Tech students I never even knew.

Oh and did I mention we made a visit to Johnson Space Center?

All in all it was a great experience educationally and socially, and I look forward to seeing everyone again during AbsGradCon. I’m not sure whose able to go to this, but maybe everyone in the group whose interested?

Research wise, its getting down to crunch time. Now that I’ve essentially got the process down, it’s a matter of perfecting my mosaic and finalizing my crater list. The preliminary work is done for most craters with topography. There may be one or two that need a bit more work, and analysis still needs to be done compared to stereo data.

So, I’ve started by creating a low resolution (32ppd) version of all my highest resolution files (256ppd and 123ppd) to sort through them all in arc to perfect the order to make sure the best images are on top. I am a little worried that lowering the resolution may make it hard to compare, but I think quality issues has to do with more than just the type of resolution used. Otherwise, the process gets harder because I only have so much storage on my laptop, and comparing files in qview or just by making picture files would be more difficult.

Thanksgiving research update (Without the thanksgiving 😞😞😞😞😞)

So I’m skipping thanksgiving this year. I’m trying to travel home less to save time and money. I am feeling a tad home sick especially now 😦 . But oh well. I don’t have a lot of content to show this week. I’ve spent a lot of time reading to for my class project and other potential projects. Although I did some work on the crater mapping.

I spent a bit of time importing the ISS map into Arc, only to realize I did it wrong because I couldn’t get the image to go under any layers. So I figured out another way of doing it, but I had a little trouble with the projection because I was working with a regular image. I ended up using the tool in Arc that lets you assign points on the picture to another point (relative to another layer). So I assigned its corners to the corners of the mosaic I already had. It sounds easy, but it’s surprising how many small issues I had that   made it a really annoyance. I’m also a little dissatisfied because I don’t like manually fixing the image. The result appears to be correct, but a more precise way would be preferred.

I know how wide and tall the image should be and know where the mosaic x,y points are. That’s how I originally fixed the original image. I gave it a specific size (in meters where its size was calculated size of Titan), and a point on the map (top right corner of Titan).

eq

However, I couldn’t figure out how to use this to define the size of the layer content. This is the x y coordinates on the shape files though. I said previously they were off but luckily it matches up to what you would expect.
Now, I don’t ahve a bunch of craters to show, but I have gone through and begun looking at the mapped craters in matlab and with SARTOPO and on ARC one by one. I’m erasing those that don’t make sense. Its tedious but its a work in progress.
I noticed a couple of the images may have been because the mosaic I used did not include a lower res image in mosiac I made the chart in. I also went and looked at  Xanadu. I found what were called craters, but to be honest several of them were unclear in my opinion which is why I probably did not get them from the start. Either way I have now.

I’m still going through ISS but first I’m trying to check the ones I already have, using ISS too.
I’ve also spoken to my old adviser Dr. Britney Schmidt and go permission to use my undergrad research to present at the Gordon conference. I’ve written my abstract for the and am going to submit it today (unless Catherine wanted to proof read it first).
Still working on my class project as well where I am comparing river orientations with existing faults.

Thats about all I’ve got for this week.

Initial results from crater mapping on Titan with room for improvement

Titan Mosaics

I have completed an initial map of Titan’s Globe, and its two Poles. I think that was the last thing we talked about. I’ve since gone through to quadruple check that I had all the images. According to my research (definitely click here), I have all the images that are publicly available.  There is one last flyby that has not been released. I have it but it isn’t correlated, which is to say calibrated to the other images such that it won’t mosaic properly. It’ll be released publicly eventually, or I may process it myself. However, it isn’t a big priority at the moment.

Crater Mapping

Using these beautiful works of art, I’ve finished the first round of crater mapping. I’m going to talk about them and how I’m analyzing them. However, I am not including the polar maps just yet. I’m working in MATLAB with the shapefiles I made in ArcGIS. That means I’m converting the spatial values in the shapefiles, which for some reason do not match up with the original projection of the imported image coordinates.

Allow me to elaborate. The first problem is Arc does not like Titan images. Even when I set the map to degrees, the center is off, and the image goes from like 90 to 180 in the middle to -180 on the other side of the middle to -90 on the other side. I may be off on that, but the general idea is that its off which makes it a hassle to locate images. Although, it isn’t much related to the actual shape files (or the image layers) because the “meters” values are way too high to be accurate for Titan, and they don’t convert to realistic degree values. The point is, it seem far more realistic to convert them to degrees using the arbitrary boundaries that seem to exist for the map. I find the upper, lower, left and right boundary values for the full extent of the entire project, then I can change that to a range from 0 to 180 along latitude and to a range from 0 to 360 along longitude. The net result took some work because obviously I made a few mistakes, but the end result looks as you would expect. The values are also consistent, for the couple I checked, with what ArcGIS says (within its warped axis labels if that makes sense).

global-crater-map.png
Global crater map of Titan (not including poles ~+/-60-90 deg)

You may think you’ve seen this before in my presentation for the Titan Surface Meeting. However, this is different. In that one, I plotted the craters and then changed the axis tick names. Now I have specific spatial values applied to each part of the craters.

Problems moving forward

There are some issues. First being that it wasn’t as straightforward for the polar maps. I decided to focus on the globe first for this discussion. However, I’m having a hard time grasping the spatial values of the polar maps. I have the same upper, lower, right and left values for the shape file. However, these don’t lie within the boundaries of the image layers as the global map did. That is one problem.

The other issue is we have maps that should span between +/-90 to +-45 in latitudes and the entire 0 to 360 in longitude. I made the mistake of assuming its as simple as up/ down and left right for lat and long in these square images. I recognize it’s not that simple. I’m confident I can figure it out with time, but I chose to handle that later. If you have any quick comments or suggestions, it would be appreciated as well.

I have ideas on how to handle the issue with the spatial values of the shape file not matching up with the image layers, but it complicates things. I need it to match up because the shape file extent is only as far as the craters go. The image files extend to the boundaries. I use the boundaries to create the conversion. If I can’t get it to match up, I’ll have to create some shape along the extents of the image files.

Crater Data

Screenshot at Nov 08 10-49-18
An incomplete table of crater data, organized from largest to smallest. See below for further explanation.

Lets talk crater data. Given my new catalog of craters, I was able to find the diameter of these craters (along lat/long). I used the Haversine Formula to convert changes in lat and long to kilometers. This seems logical. I mean I did everything right. Used the right values for the degrees. I used Titan’s radius. Except, the equation isn’t perfect. The shape files give us min/max values for lat and long, so I can do the calculation for a change in latitude or a change in longitude. Naturally, I did it for both.

Diameter Conversion
The diameter of each crater calculated using a change in latitude (y axis) and longitude (x axis). Each point is color coded based on their respective latitudinal position.

The points match up rather well. Clearly, they start to disagree for higher latitudes. In the table above, I give averaged values. However, is this the right decision? Am I overcomplicating this by doing it MATLAB instead of learning how to do it in Arc? I hope the answer is no to that last part because I’ve pretty much got this process down. Any changes to the global map can easily be processed with this code. Soon, the poles will too. Then, we throw in the topography data, and hot damn we got ourselves a new crater population.

Titan’s craters (to be organized better later)

For now, I’ve created a GIF for every crater registered. I’m going to list them here (or as many as it will let me) in descending order by diameter. I used the average values for the diameters. Let me be clear, there are a few that need to be looked at again. There are others that in retrospect should not have been plotted. Then there are a few that make no sense whatsoever. It possible some of these are indicative of a problem in my processing, but with most of them matching up so well, I don’t think thats the issue.