> 10 megapixel tiff, per square kilometer. Which I believe is roughly 35MB.
I'm sure they are using a storage medium (at a second level of compression) that provides better space efficiency than that. TIFF supports both lossy and lossless compression through extensions, but for storing source data that is used relatively infrequently (relative being the key term here), it might make sense to use a storage compression geared very heavily for space efficiency. It's not like Google doesn't have the computational power or ability to process in parallel efficiently.
I'm sure they are using a storage medium (at a second level of compression) that provides better space efficiency than that. TIFF supports both lossy and lossless compression through extensions, but for storing source data that is used relatively infrequently (relative being the key term here), it might make sense to use a storage compression geared very heavily for space efficiency. It's not like Google doesn't have the computational power or ability to process in parallel efficiently.