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Map Features Overlays on a Cylindrical Projection
post Jan 28 2012, 07:25 PM
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Thought I'd mention I'm starting a mini-project to make map feature overlays for planets and satellites. These are set up on a cylindrical projection so they can be displayed with Science On A Sphere, Celestia, and the like. The key is that text for feature names has to be "pre-distorted" so it looks correct when viewed on a sphere. This is especially important at high latitudes. The overlays are for now in the form of transparent PNG images.

So far I've started with Mars and Enceladus. The programming language is IDL, and the lat/lon info for the feature names is from the USGS Map-A-Planet Gazeteer. I'll try to post some results once they are a little better.

Enceladus is a special case, since the map I had put together is in planetocentric coordinates, and the feature lat/lons are in planetographic. So a conversion of one or the other would need to be done.


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post Feb 18 2012, 08:12 PM
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Here's Iapetus, with a 5 degree shift that appears to reconcile the image with the IAU convention of the feature longitudes.

Attached Image

Other versions can be found here (for Iapetus along with other objects):


I just figured out how to select the fonts, so future revisions should have an improved look.

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Posts in this topic
- scalbers   Map Features Overlays on a Cylindrical Projection   Jan 28 2012, 07:25 PM
- - scalbers   I have now a preliminary map of Mars with the feat...   Feb 3 2012, 06:25 PM
- - JohnVV   nice but a question on the location of 180 in the ...   Feb 3 2012, 10:49 PM
- - djellison   That's a debate that's been a part of plan...   Feb 3 2012, 11:07 PM
- - scalbers   John - I had used the 180 center longitude that cu...   Feb 3 2012, 11:10 PM
- - JohnVV   as djellison pointed out both are right i was just...   Feb 4 2012, 12:40 AM
- - scalbers   The funny thing is that the quasi-standard way of ...   Feb 4 2012, 12:55 AM
- - scalbers   Meanwhile, here's the latest with Enceladus. T...   Feb 4 2012, 02:22 AM
- - Phil Stooke   Don't get too hung up on the question of havin...   Feb 4 2012, 03:45 AM
- - scalbers   Here's Enceladus with the longitudes a little ...   Feb 4 2012, 05:09 PM
- - john_s   The longitude system on Enceladus and the other ic...   Feb 8 2012, 05:21 PM
|- - scalbers   QUOTE (john_s @ Feb 8 2012, 05:21 PM) The...   Feb 14 2012, 04:33 PM
|- - john_s   QUOTE (scalbers @ Feb 14 2012, 09:33 AM) ...   Feb 14 2012, 05:50 PM
|- - scalbers   QUOTE (john_s @ Feb 14 2012, 05:50 PM) Th...   Feb 14 2012, 06:04 PM
- - hendric   Someone should make a map with 0 Longitude going d...   Feb 9 2012, 09:20 PM
|- - scalbers   Hendric, yes that would be an interesting presenta...   Feb 14 2012, 04:28 PM
- - Phil Stooke   Re: Post 12. That is called a Transverse Cylindr...   Feb 14 2012, 04:37 PM
- - JohnVV   QUOTE Very confusing- it took me a long time to so...   Feb 14 2012, 05:56 PM
- - scalbers   Next one - here's what I have so far for Io sh...   Feb 15 2012, 07:37 PM
- - scalbers   And here is Europa with features larger than 40km....   Feb 15 2012, 08:47 PM
- - scalbers   And back at Saturn, here are the Mimas features (a...   Feb 15 2012, 09:18 PM
- - scalbers   Here's Iapetus, with a 5 degree shift that app...   Feb 18 2012, 08:12 PM
- - Phil Stooke   A very nice project, Steve - I'm enjoying thes...   Feb 29 2012, 02:00 PM

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