ire 
"he 
m-— 
he 
in 
‘ol 
ic 
  
  
  
  
  
  
  
  
  
  
  
PROCESS STRUCTURES OF 
STAGES 
PROCEDURES BASIC SPATIAL ENTITIES 
INFORMATION 
Extraction Semantic Semantic Region semantic 
domain Networks (abstract) 
| Points 
Samplin Metric Metric Strings metric 
) ere domain Chains (abstract) 
| Points 
Further Semantic Semantic Semantic and metric 
stages and metric and metric (as above & attributes) 
domains 
| iui >> 
Procedure(s) x Structure(s) 
(control data) optimize (basic inf.) 
  
  
  
  
  
  
  
Fig. 9: Process stages versus structures 
3. Specific context of data base 
The specific context refers to a specific category of information users, 
a geographic region, a sub-set of information items, a time period, etc. 
It establishes a frame of reference for the choice of information items, 
delimitation between key-items and attributes, differentiation between 
the semantic and metric domains, and for the selection (or synthesis) of 
detailed procedures and input-output structures. 
4, Classification 
Classification introduces order into information and data. A guideline 
for classification is provided by linking sequentially the influencing 
factors outlined in sections 1, 2 and 3 (figure 10). These factors repre— 
sent the successive levels of a hierarchical tree-structure. 
The feedback from "specific context" to "domain" refers, for example, to 
a generalisation process from larger to smaller map scales, whereby some 
geometric information is partly removed, partly distorted (for graphic 
reasons), and partly converted into semantic items. 
Overall system overall objectives 
————{ : 
Context system area 
Destination em e ——{ . basic 
. control 
. preparation 
Process stage aoe Ale collection 
(I/0 state) . processing 
. presentation 
Domain o. $ semantic 
. metric 
. key-items' 
. attributes 
Specific context “+ —— — —] . procedures 
. I/O structures 
Fig. 10: Levels of hierarchical classification 
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