ire of the
a general
tems, the
> Digital
te digital
different
plications
rising the
ion of the
ationship
mation.
]vantages
ely stable
space.
e time.
es with
| strateg
ntific and
wtment of
arch and
ystems to
rammetric
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
e Development and updating of digital
photogrammetric technologies over professional
platforms.
These stages are bound to the conditions in which
photogrammetry has evolved in our country as we state as
follows:
e The city of Havana accounts for a stock of universal
photogrammetric equipments from WLID (LEICA)
with 25 to 30 years of use, which are technologically
off limit.
e The universal photogrammetric Russian equipments
in different parts of the country is obsolete since the
photo format they use is 18x 18cm.
e The stock of aerocameras for 23x23cm and 18x18cm
formats are calibrated.
e The photogrammetric equipments to carry out
differential transformation and the stock for
photomechanical transformation are limited.
e There is not an advanced analytical aerotriangulation
technology.
Provided this complex reality, the development of the
automation of photogrammetry and the realization of its main
objective digital photogrammetry, have faced in almost all the
provinces what was stated before.
In the case of analogous systems from WILD (LEICA) they are
assisted by personal computers, beginning to introduce in this
way, analogous-digital technologies which conclude in digital
photogrammetric products following international standards.
Nevertheless, in our concern, this procedure should not be
applied to Russian equipments although some enterprises have
used it in order to take advantage of the available equipments.
With this technology, the internal and relative orientation
processes are made in analogue way in the equipment, and the
external orientation is solved analytically for the model,
creating a spatial mathematical model of the area to be
restituted. The restitution is achieved with the conventional
methods, except that the graphic representation of the elements
that are being obtained is stored with the geodetic coordinates
of each vertex and the code of each element.
With this aim, it was acquired the analogue — digital restitution
system ECHART which was created by LEICA and that was
designed to work graphically in exchange with the program
through Menu selections and dialogue boxes.
The release stage or outcome is done on the basis of Computing
Assisted Design CAD that allows enormous possibilities for
the digital graphic workflow and the association of the design
with the informative systems.
In the last 15 years, it has been developed the Digital
Photogrammetric Systems (DPS), which have been created for
the research groups of some European Universities that have
as principal element the Digital Photogrammetric Workstation.
It requires photogrammetric operations that may be introduced
in Digital Cartography Systems, CAD Systems, Geographical
683
Information Systems (GIS/ LIS). The final version may take the
shape of vector line maps, digital terrain model (DTM) data,
digital Ortho-Image, among others.
The DPW consists on a workstation for the graphic images
management that has powerful memory and great capacity of
data lodging including the possibility of stereo- imaging and the
proper software to support the photogrammetric performance.
Therefore, it has become an urgent need in GEOCUBA
enterprises to give priority to digital photogrammetric systems.
Different technologies have been developed (limited and
experimentally) assessing this problem. There will be a
significant change in the near future.
A few time ago, our country was provided with the technology
of this kind that consists on up-to-date digital workstations, this
gives us a leading position in the branch in the area. Also, it
enables offering leading-edge technology services of high
quality to costumers with different interests, needs, and
procedences.
The digital technology has, among others, the following
advantages:
e Dimensional stability of the digital images (no
environment affecting, no direct handing) and stability in
the measurement system since it needs calibration.
e Visualization: There are no optical- mechanical
requirements. The images can be visualized and measured
making use of data collectors with standards devices.
e Image management: The image can be improved
(brightness and contrast tracking, among others) to
optimize its visualization.
e The digital images can be transferred in a quick and
simple way through nets. Also it is possible to operate
with them in the same sequence, on the same photogram.
e — Automatisms can be done in the different photogrammetric
processes (EOI/EOE), automatic restitution of land, etc..)
e The derivative products are also obtained in digital format
(DIT, Digital Maps, Orthophotos, among others...)
e Versatility: Images are processed coming from different
sensors and in different scales.
e Traditional restitution with automatic guidance of the Z
axis.
In this way it will be necessary to continue deepening in the
different research studies in the digital stations during these
years as well as in obtaining advanced software in the field in
order to invert the situation. The methods for obtaining
aerodata, with the use of modern cameras with compensation
imagery and GPS data registering and the use of regular
satellite imagery should be taken into account since this is a line
of future development too.
If we evaluate the automation of photogrammetric processes
with cartographic purposes in Cuba it could be observed that
there have been a technological culture in all its development, a
technical personnel prepared for the activity and equipment
which have made possible a steady and ongoing development.