Sportage ground clearance looks higher and reason is you are seeing a taller vehicle, with bigger wheels , bigger wheel arches with respect to Corolla or any other vehicle and which gives perception of a vehicle with higher ground clearance.
Measurement are not taken on basis of one's perception. It is taken with a standard and in this case a measuring tape or any other measuring tool. If PKDM Sportage spec says 172mm.. it will be 172mm for Sportage with stock wheels and designed suspension, air pressure in tires.