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Cassini image database & updates, And notifications of PDS data releases
volcanopele
post Apr 2 2007, 08:43 PM
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http://pds-imaging.jpl.nasa.gov/data/cassi...assini_orbiter/ works fine for me right now.


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volcanopele
post Apr 2 2007, 08:50 PM
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Some highlights from my perspective are the T13 radar SAR swath (the one that crosses Xanadu) and the distant encounters with Janus and Pan.


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ugordan
post Apr 2 2007, 09:14 PM
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Here's Janus, an approximately natural color view and enhanced stretched color to bring out subtle color differences:

Unlike Telesto which appears bluish in natural color and very faintly orangish in stretched color, Janus is more like other rocky moons -- Prometheus and Pandora. Magnified 2x.


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elakdawalla
post Apr 3 2007, 12:07 AM
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QUOTE (Bjorn Jonsson @ Apr 1 2007, 10:08 AM) *
I could make the database available if someone can host it, it's too big for me to do so (about 55 MB zipped). It contains all of the information from all of the index.tab files on volumes COISS_1001 to COISS_1009 and COISS_2001-COISS_2023.
After a bit of a tussle with the remote server I've managed to upload the file, so it's now hosted at:
http://filicio.us/tpss3/files/17314/cassini_images.zip

It's 55 MB and unzips to a 500-MB database. I'll let Bjorn chime in with any comments he'd like to make about it. For my part, I'll just thank Bjorn for assembing this whole thing -- and beg for the inclusion of the north_azimuth field that you calculated for some Saturn images for all the images in the next version of this database.

--Emily


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Bjorn Jonsson
post Apr 3 2007, 05:19 PM
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A few comments:

This is a Microsoft Access database containing two tables, coiss and coiss_revised. Coiss simply combines all of the index.tab files on the Cassini ISS volumes 1001-1009 and 2001-2023 into a single database without any significant modifications, except for the rejection of erroneously formatted numbers (see the list of errors at the end of this message).

The coiss_revised table contains updated values for a few fields. These values are *probably* slightly more accurate (from my experience when doing a cylindrical map of Saturn) than the original values although I cannot completely guarantee this. They are computed from the latest SPICE kernels (CK and SPK). The NORTH_AZIMUTH value is also included as there's no equivalent field in the coiss table. At this time only a few images are included in coiss_revised. I don't know the exact geometric meaning of north_azimuth_clock_angle in the index.tab files but it is totally different from north_azimuth so I added north_azimuth in a separate table. However, I have only determined it for a few images (70 - mostly the ones I used to do a map of Saturn) but plan to do so for all of the images, possibly before the next batch of images gets released 3 months from now.

There are a few simple queries there as well that I decided to include as a simple example of what can be done.

I use this database extensively when searching for interesting and/or specific images, both from within Access and directly from programs I have written. I rarely use the PDS to search for images, I mainly use it to download entire data volumes.

As previously mentioned I found errors in some of the index.tab files. The errors I know of are:

coiss_2017: There are erroneously formatted floating point numbers in rows 1253-1257 in index.tab, columns 2541-2551 (SUB_SPACECRAFT_LATITUDE). I tried 'guessing' the correct values. These are images N1512191594_1.IMG, N1512191728_1.IMG, W1512191728_1.IMG, N1512191860_1.IMG and N1512191993_1.IMG.

coiss_2020: There are erroneously formatted floating point numbers in rows 170-171 in index.tab, columns 2628-2638 (TARGET_SOUTHERNMOST_LATITUDE). I fixed this manually - the fixed values are a guess and the correct value to use is uncertain. These are images N1517273822_1.IMG and N1517273855_1.IMG.

coiss_2021: There are erroneously formatted floating point numbers in rows 1980-1990 and 2648-2649 in index.tab, columns 2541-2551 (SUB_SPACECRAFT_LATITUDE). I fixed this manually - the fixed values are a guess and the correct value to use is uncertain. These are images W1520869299_1.IMG, N1520869388_1.IMG, W1520869388_1.IMG, N1520869616_1.IMG, W1520869616_1.IMG, N1520869705_1.IMG, W1520869705_1.IMG, N1520869934_1.IMG, W1520869934_1.IMG, N1520870023_6.IMG, W1520870023_1.IMG, W1521409807_1.IMG and N1521409944_1.IMG.

coiss_2023: There are erroneously formatted floating point numbers in rows 2785-2788 in index.tab, columns 2616-2626 (TARGET_NORTHERNMOST_LATITUDE). As previously I fixed this by trying to guess the correct values. These are images N1530372696_1.IMG, N1530372841_1.IMG, N1530372986_1.IMG and N1530373131_1.IMG.

There might be more errors.
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tallbear
post Jun 8 2007, 09:07 PM
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Is there any sort of search capability in existence for any of the PDS ISS released products ??

For instance... if one wanted to look for NAC images where the boresite intersect was in the B-ring
and the range was under say 10 Rs ??? or where the target was PROMETHEUS and the range was under
1M km ??

my first impression is that the INDEX.TAB files *seem* to have some problems ... but perhaps I've not
gone thru enough documentation .... any pointers on documentation source would also be great !!

Thanks !!
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elakdawalla
post Jun 8 2007, 10:21 PM
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I'd say the best thing to use to search would be Bjorn's database, referenced earlier in this thread. He's already got basic queries on some targets with ranges in there -- they'd be easy enough to modify to get your Prometheus-under-1Mkm search, but I don't know how you'll do the B-ring one.

Bjorn, if you update your database with the tables of info from the latest release I'll gladly host it for you.

--Emily


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Bjorn Jonsson
post Jun 9 2007, 12:58 AM
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What tallbear wants to do should be trivial to do in my database, in fact the reason I made the database was that I wanted flexible search capabilities. The Prometheus-related query is trivial (there are similar sample queries I did in the database where the target is different but they illustrate how to do this).

The B ring query is probably easy as well although I should mention that I have not tried something like it (I'm on my laptop at the moment and the database is on my desktop computer so I cannot try it at the moment).

I didn't notice any problems with the INDEX.TAB files except for the ones mentioned in my April 3 message earlier in this thread. The database contains all of the fields/columns from all of the index files.

QUOTE (elakdawalla @ Jun 8 2007, 10:21 PM) *
Bjorn, if you update your database with the tables of info from the latest release I'll gladly host it for you.

Great! I will be updating the database in early July following the July 1 PDS release. The updates can be imported into the database so I do not have to upload the database again in its entireity when I update it.
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tallbear
post Jun 9 2007, 04:37 AM
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Cool... I'll try Bjorn's database....read over what it takes to get it up and running....
It's interesting that the Rings Node has really neat search capabilities for Voyager
images... but for Cassini ... it's unmannedspaceflight.com that's forging the way ....
...Thanks ... Great Work ... I'll get in and start nosing around...
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Bjorn Jonsson
post Jun 29 2007, 07:50 PM
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The July 1, 2007 PDS Cassini release is starting to appear. The ISS and VIMS stuff is already there:

http://pds-imaging.jpl.nasa.gov/data/cassi...assini_orbiter/

So far I have downloaded only about 1500 ISS images and have looked at only a few of them but there's one particularly interesting imaging sequence in this release: The ISS data includes the famous imaging sequence showing Saturn and the rings backlit with the Earth visible as a tiny bright spot. That particular imaging sequence starts in directory data/1536725883_1537013377 on the coiss_2025 volume.
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elakdawalla
post Jun 29 2007, 08:32 PM
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Cool!

I've been wanting to do something to make PDS Cassini images easier to find but this data set is way too big for me to do a complete treatment on it. Instead, I was thinking of producing an index page to all moon images where the moon spans more than N pixels. The thing is I haven't decided what N should be yet. 200? 100? 128? What's a good number? I'd probably use a different number for the major icy sats than for the ringmoons and Lagrange point moons. Any thoughts?

--Emily


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scalbers
post Jun 29 2007, 09:39 PM
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Emily,

That would be pretty neat to see an index. From my perspective it sounds like you have some good numbers in mind. In the case for some of my maps I've used images getting down to just over 100-120 pixels, though most are over 200.


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djellison
post Jun 29 2007, 10:03 PM
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What would the diameter be for the middle of the disc to be 1 degree of latitude / pixel. That might be an appropriate figure to work from. My brain can't do the trig to figure it out smile.gif

Doug
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scalbers
post Jun 29 2007, 10:10 PM
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Maybe 115 pixels?


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ugordan
post Jun 29 2007, 10:18 PM
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Yeah, it could be 115. 1/sin(0.5 deg).


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