2. PHOCUS 
2.1 Object-oriented data acquisition in PHOCUS 
MEOD (measure object data) is the central program for object-oriented data 
acquisition in PHOCUS. The objects to be measured are entered in an object 
code table, whose contents can be freely defined and therefore easily adapted 
to a wide variety of requirements. 
During measurement, the collected data are stored in a structured form in the 
data base, but at the same time they can also be logged on several graphic 
output units. The VIDEOMAP and StereoVIDEOMAP are valuable aids here for the 
operator as they enable the direct comparison of the collected data with the 
aerial photo. A special feature of the graphic display terminal is the possi 
bility of guiding the currently used display window along with the floating 
mark movement. This ensures that the current section of the field of view is 
always displayed, even with high magnifications. 
The linking of elements to existing objects or object items is performed by 
the SNAP functions. This way, the topological relations between the objects 
are established and implemented in the data structure. 
All editing functions are already available during data acquisition, permit 
ting the immediate correction of detected errors. In particular the functions 
Snap, Delete last point/object etc., which are of special relevance for the 
operator, ensure the acquistion of a data base where the necessity of subse 
quent editing has been substantially reduced. 
The results of additional, geodetic measurements - e.g. roof projections, 
completion of partly concealed objects etc. - can be integrated during or 
after the measuring process on the instrument.