New approaches in the measurements and analyses with LEED and RHEED lead us to another view of these techniques as a scan method for a wide-range of crystal reciprocal space. Recent progress of the constant momentum-transfer averaging (CMTA) method for LEED structure analysis and development of Weissenberg RHEED method, in which a principle of a Weissenberg Camera for X-ray crystallography was imported to RHEED measurements, are briefly introduced in this review. Both methods capture a huge number of diffraction patterns, and can survey a crystal reciprocal space in three dimension. It is possible to determine the surface structure directly from a simple analysis based on a Fourier transformation of the obtained reciprocal data.