Is Reference3D 100% produced from HRS data?
Reference3D is mostly derived from HRS, but not necessarily 100%. Since HRS revisit capability is only 26 days, we envision that the collection of absolutely cloud-free data over every acre of land could be very long in some areas. That is the reason why it is planned to complement Reference3D with external data : SPOT stereopairs, ASTER, SRTM (DEM layer only), The quality layer will register the corresponding mentions.
