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INCOME (INFOCAM COMPILATION OF MAP ELEMENTS), as 
the photogrammetric data capture module of 
INFOCAM/MAPIT, allows with an analytical stereo 
plotter, such as the Leica SD2000, the on-line 
capture of large volumes of unstructured three—- 
dimensional vector data (mainly POINTS and LINES) 
and the automatic structuring of the topology. 
INCOME supports fully the image superimposition of 
the SD2000 (COLORISS) and of the DSR 15 (KRISS). 
The INCOME module comprises the following three 
sub-modules: 
— COLLECTOR 
- TOBUI (TOPOLOGY BUILDER) 
- EDITOR 
5.1. STEP A / COLLECTOR 
The most important tasks can be described as 
follows: 
- recording of  zero- and one-dimensional 
geometrical elements (points and sections of 
line called "spaghetti") 
- assignment of thematic codes 
- placing of region seeds for the subsequent 
formation of areas 
- setting thematic labels for the subsequent 
attachment of attributes. 
At the conclusion of Step A, each zero- and 
one-dimensional element is available on its own. 
The relationship between the elements has not yet 
been established and the connection between 
attributes and their subsequent owners is only 
implied (by their relative positions). 
5.2. STEP B / BUILDER - Part 1 
  
The most important tasks can be defined as follows: 
- determination of topological relationships 
- intersections of lines and the determination 
of nodes 
- elimination of sections of lines, which occur 
more than once, 
- marginal lengthening or shortening of lines in 
those cases where a node can be created within 
the tolerance band. 
This step is performed automatically without 
intervention by the user. The corresponding 
BUILDER RULES to be observed can be defined in 
advance. At the conclusion, a valid edge/node 
Structure has been completed and the data are 
topologically consistent. Thematic lines and areas 
(regions), however, have not yet been created and 
neither has the explicit assignment of thematic 
groups and attributes taken place. 
13 
5.3. STEP C / BUILDER - Part 2 
  
The most important tasks can be defined as follows: 
- automatic determination of symbol, line and 
region elements on the basis of thematic 
criteria and rules defined at the beginning of 
the procedure (BUILDER RULES). 
- Firstly, symbol points are transformed into 
symbol elements. However, since a symbol 
point can have several thematic codes, some 
points will result in several symbol elements 
having the same geometry. 
- The mosaic of edges, which was created in the 
preceding steps, is then reduced to line and 
region elements on the basis of the thematic 
codes attached during data acquisition. 
Connecting edges with a common thematic (line) 
code become a line. 
Edges, to which a region code was attached, 
are included in a region construction process. 
This process starts at a node and searches for 
the shortest possible route back to the 
starting point. 
The process is repeated as many times as is 
necessary. 
  
SPAGHETTI 
  
  
  
    
    
TOBUI 
  
  
  
  
  
       
   
       
  
     
  
  
  
Program 
INCONSISTENCIES supported 
a data cleaning 
Error Ambiguities - ° 
: Editor 
  
  
  
  
  
  
  
  
  
  
ELEMENT 
(Symbol, Line, Region) 
  
  
  
Fig 3: Data flow in the Topology Builder 
Problems are registered by the system and can be 
processed interactively (INCOME EDITOR) after the 
automatic procedure has finished. Finally, the 
attributes are assigned to the symbol, line and 
region elements, which have been created during 
this step. At the conclusion of Step C, the data 
are available in a thematically and topologically 
correct form. 
6. POSSIBILITIES AND LIMITATIONS OF 
AUTOMATIC STRUCTURING 
A characteristic of INCOME is that it tolerates 
errors which can be both to the user’s advantage or 
disadvantage as the case may be. 
One advantage is most certainly that a number of 
"trivial" errors such as the merging of closely 
adjacent points and cases of slight overshooting 
and undershooting are corrected automatically by 
the system itself, and that the user does not have 
to explicitly define thematic significance and 
certain of the attributes, but simply implies them 
by stating the location (REGION SEEDS and LABELS).