A map of Europa
This map of Jupiter's satellite Europa was created by taking the Europa map from the US Geological Survey (USGS) that was created from Voyager spacecraft images and replacing almost all of it with higher resolution images from the Galileo spacecraft. I used a total of 14 Galileo images (the so called G1, G2, E4, E6, G7 and C9 images) and used the viewing geometry information embedded in the image files to project the images on a cylindrical map and at the same time using information on illumination conditions to remove the effects of different illumination. Following this, removing the seams between all these images, completely adjusting for different illumination conditions between the various images and doing other cosmetic enhancements was a lot of work but I was happy with the result. As a final step I used several Voyager 1 and 2 global images to colorize the map.
You can view the full size version (235 KB 1800x900 pixel JPG) by clicking the map below. The text below contains more details on it for those interested.
In fact my original version of this map is 3600x1800 pixels which is too big to include here. This map should be pretty accurate, there were no big discrepancies between the location of features in the Voyager and Galileo frames, indicating that the location of features on the original Voyager map was accurate.
I made cosmetic enhancements in several places, most notably southwest of the bright crater Pwyll and in a narrow, horizontal strip in the southern hemisphere right of center (there was an ugly gap there in one of the Galileo images). I also removed the seams between the individual frames used to create this map. Following this I removed blank (black) areas near the poles by painting in smoothly colored areas and/or cloning adjacent areas. This means the southern/northernmost areas are fictional. A "mask" showing the extent of the fictional areas near the poles can be viewed here. The final step was to colorize the map from lower resolution global Voyager images.
The map is in simple cylindrical projection with latitudes running with a uniform interval from -90 (bottom) to 90 (top) and longitude 0 at the left edge of the map. It should be rendered by projecting it onto a sphere of 1565 km radius or some equivalent unit. See also my planetery rendering tips page for further info.
This map is better and more realistic than the map at David Seal's site since that map is based on Voyager imagery only (which is older and inferior to the Galileo imagery I used). That map also seems to be based on "hand-drawn"/airbrushed maps of Europa by the USGS instead of being created directly from spacecraft photos.
In the fiuture I plan to do an improved map that will incorporate more recent Galileo data than this map does. In particular, fairly high resolution images are now available for the right half of the map which is rather fuzzy in the map above.
23.05.1998: First version of the map, based on the G1, G2, E4, E6 and G7 images from the Galileo spacecraft and Voyager data where Galileo data was not available (mostly the right half of the map).
01.10.1998: Added the recently released C9 data from Galileo. This improved the resolution in the right half somewhat but it is still low. After this change, very little Voyager data remains. Also removed a dark feature northeast of the Tyre impact basin after I found it was spurious (it shows up as a dark, circular spot in the original G7 Galileo image but is not present in any of the Voyager images).
29.03.2002: Replaced the map with a version that has a more realistic color and brightness. The color is no longer synthetic, it is now taken from Voyager 2 global images. In particular, the hemispherical color difference is now visible. The map is also considerably brighter than before, reflecting the fact that Europa is a very bright object. Now the only remaining problem is the right half of the map which needs to be replaced with the higher resolution data that has been available for some time (or maybe I'll replace the entire map).
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