Thanks, a nice resource. Hmm, I'm wondering how to make some user-creatable land types. The Blue Marble basically give the color of a 500x500m cell. MODIS dataset, from which the Blue Marble was derived, contains several infrared and visible color bands and is able to tell a rough land type from these parameters. However, the type is quite rough, and BM contains far higher variation. My original idea was to get resources for major land types, get their color appearance, temperature and precipitation ranges, and run it over the whole dataset to select the best match for each pixel.
Then if someone produced a new land type, picked one area where it occurs (by color or other factors), it could be detected the next time the processing runs.