Discussion of ‘Some limitations in the interpretation of vertical stereo photographic images for a landslide investigation’ by A.B. Hart, J.S. Griffiths & A.E. Mather, Quarterly Journal of Engineering Geology and Hydrogeology , 42, 21–30

Abstract

Roly Edwards writes: Having been centrally involved in the early development of terrain evaluation for engineering practice there are two matters of fact, which are misreported in what is otherwise a useful contribution drawing attention to the value of the use of land surface evaluation techniques for land stability studies. First, in their resume and evaluation of the use of vertical stereoscopic aerial photography in the investigation of the nature and distribution of landslide features in the Rio Aguas catchment in Spain, the authors suggest that stereoscopic images in the non-visible part of the electromagnetic spectrum were unavailable until the launch of SPOT in 1986. I would remind them that false colour IR and multispectral stereoscopic aerial photography at 1:5000 and 1:10 000 scales was routinely available, at a cost, as long …