The SCALGO terrain data-processing technology is based on more than two decades of basic and applied research on algorithms for handling massive data, in particular so-called I/O-efficient algorithms and geometric algorithms with fully-specified output. With it you can efficiently handle much larger terrain datasets on a normal desktop than most current software and thus eliminate the need for accuracy-decreasing data thinning. The use of novel mathematical and algorithmic techniques also means that the software works provably efficient on all input datasets delivering a completely specified output without the use of cumbersome workflows such as those introduced by data tiling.