The land surface of the Earth is over 300 million square miles. Mapping to the same accuracy (1/50 inch on the printed map) as the USGS 7.5 minute topographic maps on a raster scan would require something like 1.3 terapixels (that's 1.3 trillion pixels). You probably want finer resolution, perhaps 600 dots per inch, which boosts the number to 190 terapixels, each of which has associated altitude information and thematic information (vegetation cover, highway type, things like that). Numbers like that show what a huge job it will continue to be to produce detailed maps of the whole world. Maybe you can get away with an altitude grid that is a coarse as the finer parts of the USGS DEM grid (Digital Elevation Model). But this will perhaps give you an appreciation of the accomplishment of those who surveyed just the 48 contiguous states on foot and by hand, only a few million square miles out of the Earth's land surface. There are still parts of the US (Alaska, in particular) that are incompletely mapped to the 1:24,000 scale, and large parts of the world that are mapped only to the 1:500,000 scale, and even areas that remain completely unmapped except for satellite photographs and crude sketches.