Of Jupiter's Galilean satellites, Europa has the best imaging coverage. Much of the surface has been imaged at a resolution of 1 to 4 kilometers per pixel. There is also significant coverage at about 200 meters per pixel, plus small areas at higher resolution, in some cases down to 10 to 20 meters per pixel. But there are also large areas that are poorly imaged. Several global maps have been made of Europa but I felt they could be improved so I decided to make a new one. An important factor is also that no spacecraft that can image Europa well enough to make a new map outdated is going to arrive at Jupiter until the late 2020s at the very earliest (but of course I would love to see my new map become completely outdated as soon as possible!).

To make a map of Europa it is necessary to reproject the spacecraft images to a common projection -- I use simple cylindrical projection -- and then seamlessly mosaic them into a big map. I started by making a global full-color map from the available global color coverage. The best resolution of this color data is approximately 1.5 kilometers per pixel, but the resolution is worse in large areas (typically about 7to 15 kilometers per pixel). I then added the higher resolution data (most of it about is 200 meters per pixel but in some cases the resolution is higher or lower) to the color map. Almost all of the high-resolution data is monochrome (grayscale). High-resolution grayscale data can be added to a color image in Photoshop by making an intensity layer, pasting the grayscale data into that layer and then adjusting brightness and contrast in that layer. The result is an image where the topographic details come from the high-resolution grayscale data, and the color is from lower-resolution color data.