954 
sources derived from the aerial and space 
multispectral imagery. 
The cartographic material users are accus 
tomed to have maps as a graphical or photo 
graphic representation, which contents could 
be read, studied and on which they can work. 
That is why, a plotter is supplied to the ne> 
cessary hardware to compile a digital map, 
in order to draw a classical map, as well. 
To compile a digital map, therefore, a cer 
tain technological development stage is re 
quired, namely, the existence of a topogra 
phic, photogrammetric, and remote sensing 
equipment able to record digitally, a compu 
tation unit with a proper software to process 
data , a geodetic and cartographic data bank 
including a data base for digital maps, and 
a plotter, as well. 
Although the scale has not the same meaning 
for a digital map as against the classical 
one, it was established to use a symbol for 
each conventional sign being in a biunivocal 
relation (Figure 3), just to make a graphical 
representation, when required. 
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Figure 1. Diagram of the land cadastre struc 
ture and their connections with special ca 
dastre. 
sources are becoming more and more complex, 
and thus, the classical cadastre is gradual 
ly transformed into a more complex one, that 
is an ensemble of land information systems, 
able to answer the many various problems in 
due time. In this respect, there is a ten 
dency to compile digital maps, an almost new 
established concept, meaning a digitally 
stored data collection representing a map 
contents (StefanoviS 1980;. Considering digi 
tal map features, we easily can understand 
the technological process (Figure 2) used to 
compile it, where data employed are automati 
cally processed (Zegheru 1981). 
Figure 2. Input data sources, the main tech 
nological process stages in digital mapping 
and final results. 
The previous diagram obviously illustrates 
that input data can be derived from topogra 
phic and photogrammetric surveys, some exis 
ting maps or document digitizing, photogram 
metric and remote sensing data and informa 
tion. In digital mapping technology, geodetic 
and cartographlo data base is an oompulsory 
element to deliver data during the processing 
stage, to store these map contents and other 
information related to the national land re- 
Flgure 3. Diagram of connections among topo 
graphical elements, conventional signs and 
codes. 
Errors due to drawing and its base are ad 
ded to the measuring and data processing er 
rors during classical map compilation. In 
this way, the digital map proofs to be more 
accurate that the classical one. 
The following reasons are in favour of the 
digital mapping technology: updating map sim 
plification, maintaining the accuracy in new 
and modified elements introduced in the ori 
ginal map; simplification of the map compila 
tion having various themes derived from the 
same original map: various thematic maps 
could be derived from a topographical map, 
using a display or a plotter; a shorter time 
between data collection and map editing sta 
ges; the possibility for a manifold analysis 
of information derived from the map contents 
and their various thematic processings; the 
possibility to automatically generalize from 
the digital map to smaller scale classical 
maps, according to the data base files. 
The existing data base was conceived to 
store 1:5,000, 1:2,000 and 1:1,000 scale di 
gital cadastral maps, using analytical photo 
grammetric methods (Zegheru et al.1982). A 
conventional sign atlas suited for the auto 
matic cartographic requirements was developed 
to carry out this data base on files corres 
ponding to the above mentioned scales. These 
conventional signs were coded considering both 
connections among symbols, representing the 
same object at various scales, and data re 
trieval for different themes (Figure 4) (Fu- 
soi et al. 1981). 
The digital cadastral map contents are 
stored on a scale file, according to its con 
tent and accuracy. The derived map and plan 
information is prepared at the drawing scale, 
and after its cartographic representation, 
nothing is to be stored in the data base. 
Among the important facilities of the digi 
tal mapping technology at the same time, be 
ing also the main reasons for digital cadas 
tral mapping, we can mention storage, their 
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