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My Ganymede mosaic, Made by hand, around 1999
EDG
post Oct 18 2010, 03:36 AM
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This is a colour global view of Ganymede, taken using Orange, Blue and Violet images (in the RGB channels respectively) from Voyager 2. I made it using ISIS around 1998 or 1999, it's an orthographic reprojection of a mosaic of the antijovian hemisphere. I don't think I stretched the histograms in the component images at all.

I wish I could remember what specific images I used (I'm reasonably sure that I was using the images that start around C2063105). Annoyingly I can't find my notes on it - I'm lucky I actually managed to find the image itself! smile.gif. I think there were around 39 images in total (about 13 for each filter)?

I do remember that I had to manually match the images - I didn't have IDL or any of that other fancy stuff, working in a UK university that didn't have the funds to buy it. I looked at each adjacent/overlapping image pair in a given filter, looked for a minimum of three match points between the images, and noted down the pixel locations for all of them in a little black book and in a text file that ISIS would read, and then did that several times for each overlapping image pair - it took weeks to find all the match points, and sometimes ISIS would still just not match the darn thing properly and so I had to go back and find different ones. As it is it nearly broke the computer I used to make it (which of course was great for the time and completely laughable by modern standards), and I think the end mosaic (in original .cub format) was over a gigabyte in size! I'd have to leave the ISIS script to take it from level 0 to level 4 running overnight and hope it all worked. I also used updated SPICE data for Voyager that I got from Tim Colvin at RAND Corporation (that IIRC wasn't in ISIS at the time). The resolution of the mosaic is 2 km/pxl.

Probably not awesomely useful for science, but I'm pretty proud of it considering the effort it took to make it - hope you like it smile.gif.
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elakdawalla
post Oct 19 2010, 06:26 PM
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Since the scripts are just text files and shouldn't take up too much space, I say post 'em. I have fantasies that I'll get back into using ISIS for image processing but I'll have to get myself a Mac first...


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- EDG   My Ganymede mosaic   Oct 18 2010, 03:36 AM
- - DrShank   >>I wish I could remember what specific imag...   Oct 18 2010, 01:35 PM
|- - tedstryk   One of my Ganymede mosaics uses that set with wide...   Oct 18 2010, 04:28 PM
- - EDG   Only 18 images? Seemed like a lot more! (maybe...   Oct 18 2010, 06:17 PM
|- - ugordan   QUOTE (EDG @ Oct 18 2010, 08:17 PM) So ba...   Oct 18 2010, 06:41 PM
- - EDG   Very nice! Thanks for doing that, I've of...   Oct 18 2010, 07:23 PM
- - DrShank   its about as close to natural color (at high resol...   Oct 18 2010, 11:46 PM
- - EDG   Hooray! I just managed to find all my old Gali...   Oct 19 2010, 08:10 AM
- - tasp   Thanx!!   Oct 19 2010, 05:32 PM
- - elakdawalla   Since the scripts are just text files and shouldn...   Oct 19 2010, 06:26 PM
|- - EDG   QUOTE (elakdawalla @ Oct 19 2010, 11:26 A...   Oct 19 2010, 07:10 PM
- - Bjorn Jonsson   Great mosaic, especially when keeping in mind that...   Oct 19 2010, 06:48 PM
|- - EDG   QUOTE (Bjorn Jonsson @ Oct 19 2010, 11:48...   Oct 19 2010, 07:11 PM
- - EDG   This is the global mosaic of Ganymede's traili...   Oct 19 2010, 07:17 PM
- - EDG   I was going to start a new thread for this but I t...   Oct 20 2010, 07:37 AM
|- - tedstryk   Cool. That looks like the set I used in this one....   Oct 20 2010, 05:20 PM
|- - EDG   QUOTE (tedstryk @ Oct 20 2010, 10:20 AM) ...   Oct 20 2010, 05:52 PM
|- - ugordan   EDG, any idea why you have color shifting in the 3...   Oct 20 2010, 06:20 PM
||- - EDG   QUOTE (ugordan @ Oct 20 2010, 10:20 AM) E...   Oct 20 2010, 06:47 PM
||- - ugordan   QUOTE (EDG @ Oct 20 2010, 08:47 PM) Are y...   Oct 20 2010, 06:51 PM
||- - EDG   QUOTE (ugordan @ Oct 20 2010, 11:51 AM) Y...   Oct 20 2010, 08:34 PM
||- - tedstryk   I didn't notice that problem.   Oct 20 2010, 08:37 PM
|- - tedstryk   I am trying to find my notes...I did that image th...   Oct 20 2010, 07:27 PM
- - EDG   To correct the blurriness (aesthetically anyway), ...   Oct 20 2010, 07:40 AM
- - EDG   The next attempt is actually as close to true colo...   Oct 20 2010, 07:49 AM
|- - ugordan   QUOTE (EDG @ Oct 20 2010, 09:49 AM) All t...   Oct 20 2010, 08:13 AM
|- - tedstryk   QUOTE (ugordan @ Oct 20 2010, 09:13 AM) P...   Oct 20 2010, 05:22 PM
- - EDG   And finally, just for kicks I tried an OGU image (...   Oct 20 2010, 07:52 AM
- - EDG   I've found the scripts for the Voyager 1 mosai...   Oct 21 2010, 05:24 AM
- - ngunn   Titan has veiled wonders and Io suppurates, but to...   Oct 21 2010, 10:35 PM
|- - EDG   QUOTE (ngunn @ Oct 21 2010, 03:35 PM) Tit...   Oct 22 2010, 07:06 AM
- - Decepticon   EDG Have you done other moons? Europa maybe?   Nov 23 2010, 05:59 AM


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