proto- 
respect 
er ofa 
Shape' 
in geo- 
Ting"), 
rs that 
erime- 
on, ori- 
again a 
variate 
escribe 
jects in 
icter, it 
h well- 
S or S- 
1iversal 
ession', 
ed in a 
core, it 
ulations 
olume!, 
by sim- 
h with a 
dough- 
ved as a 
he func- 
plemen- 
but the 
Geodata 
umber of 
tive user 
djust the 
nly those 
k will be 
ıb-menus 
omorphic 
S. Rather 
se opera- 
e is used. 
; and per- 
e Platform independence 
Since VGIS is developed independently from the under- 
lying GIS, users may exchange workflows without need 
to adapt them to particular environments. 
e Automatic generation of flow charts 
This feature is reserved to a future version of VGIS. 
e Self-documentation through storage of processing plans 
that capture lineage 
Processing plans can be saved and modified anytime. 
The user may enhance results by iterative changes of the 
raw 
image 
analog digital 
map map 
elevation 
data 
soc.-econ. 
data 
  
workflow depicted in the processing plans. Data be- 
comes self-documenting because the processing plans 
contain their lineage. 
Flow charts are a the standard process-oriented tool in visual 
programming (Chang 1990, Glinert 1988, Monmonnier 1989). 
Such a visual programming example is depicted in Figure 8, 
where the modeling flow chart allows the user to "play" with 
the data flow. Within VGIS, it is easy to test the result of new 
routing paths within the flow chart. Different hypotheses can 
easily be tested by adding or changing a connection of the flow 
chart. A similar reconfiguration of a conceptual model would 
require substantial GIS expertise if it were attempted in a ven- 
dor GIS. 
  
result 
  
  
  
processing 
  
   
  
VGIS flow 
  
  
   
    
  
   
     
flow 
chart 
generating 
tool 
data management 
   
thematic 
data 
    
geometric 
data 
chart 
interpreter 
  
data analysis 
  
  
    
   
   
- theme 
     
    
methods 
- geometry 
Figure 2. The VGIS design 
83 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996