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.
