INTRODUCTION 
It is the purpose of this report to review the present 
situation regarding those photogrammetric errors occurring 
up to the moment of placing a plate into an instrument for 
photogrammetric mensuration. It is not possible, however, 
to exclude the mensuration process completely from the 
discussion, because knowledge about the actual dimensions 
can only be attained from measurements. In order to 
eliminate measuring errors as far as possible, an accurate 
comparator has been used. 
The discussion of sources of image geometry changes 
will follow the sequence of their actual occurrence. 
The paper consists primarily of a review of material 
published since the last congress of the International 
Society of Photogrammetry. In addition, so far unpublished 
results of this reporter have been included for two reasons: 
firstly, to fill certain gaps which remained after the 
review of published material and, secondly, to provide for 
consistent examples throughout this report. 
The first two sections will set out certain definitions 
and explain the method for the presentation of the effect 
of the various errors on the image geometry. The following 
sections will be devoted to the discussion of a larger number 
of sources of image geometry changes. They will be followed 
by a short review of material published regarding image 
deformation correction, a summary and conclusions.