The scalar product with its essential constructive element of orthogonality 
thus allows the use of a uniform calculus. So the digital components of qeo- 
informatics (data and processes) - supplemented by distributions - can be 
described. 
alues 
4. Functional analytical description of digital photogrammetric processes 
lp of 
cients 
The examined here geoscientific facts are described by two space co-ordinates 
and one character vector. Thereby the field altitude is not considered as 
equal co-ordinate direction, but as character for the situation point. 
nee: 
In /2/ the specific characteristics of photogrammetry and remote sensing were 
differentiated from each other. One crucial point of digital photogrammetry 
is the obtaining and the transformation between digital images. Special 
problems thereby are the assignment of values in the quantization and the 
specific form of resampling in form of digital filters. 
From Figure 4 becomes clear, that between the purely analogue and digital 
images internal data structures exist, which are adjusted to the problems and 
thus are effective. 
tract 
The digital data structures either are digital raster images or derived 
structured data. Digital images are characterized by sequences of numbers, 
omponents 
al 
which can be understood as weights of spatially displaced ¿"-distributions 
(compare formula (1)). Derived structured data generally describe objects by 
their geometry and features. Because essential topographic objects often are 
pointlike or linear, vector-oriented descriptions are preferred. In Table 2 
every 
ich 
raster and vector representations for some tasks are compared. 
Transformations of digital photogrammetry can be divided into 
ant, 
(I) data structure changing and 
as 
alence 
(II) data structure preserving. 
izations 
(I) In these transformations also the qualitative level of data is changing, 
what - as a rule - has also influences onto the data amount (high level 
ations 
of data base - relatively small data amount and vice versa). 
composes 
ces of 
Examples: 
digitizing operator and its inversion; 
(see 
integral transformation between space and frequency range; 
339