Reprint of Norsk tidsskrift for jordskifte og landmäling, nr. 1/1968 
The influence of height differences on the accuracy 
of the stereo-model. 
By I. Hädem 
Institute of Geodesy, the Agricultural College of Norway, Vollebekk. 
XIth International Congress for Photogrammetry, 
Lausanne 1968. 
Paper presented to Commission II. 
1. Introduction. 
The influence of errors in the inner orientation and of ob- 
servational errors in parallaxes and coordinates on height and 
on the residual parallax in the cases of convergent and vertical 
photography has been theoretically investigated in [1], under 
certain assumptions about the shape of the terrain. The present 
paper deals with a further examination of the influence of the 
above-mentioned sources of errors on planimetry and height and 
on the residual y-parallax in the case of vertical photography. 
A bibliography is given in [1]. 
2. Assumptions and basic formulae. 
The coordinate system and the directions of the axis and 
rotations are defined as shown in Fig. 1. 
X Je 
EN Kk 
I Xy 
X Fig. 1. Coordinate systems and direc- 
= tions of relations.