| dc.description.abstract | In many types of surveys, it is essential to have
ground control points. These are points on the ground
whose coordinates are known in a ground system to a
certain standard of accuracy .
. A situation arises when the number and location
of control points is not sufficient for the intended
survey. The process of increasing the control points is
normally referred to as Densification of Ground Control.
Traditionally, the densification has been carried out by
, . ground methods through traversing, triangulation,
trilateration etc. With th~ present high accuracy of
some photogrammetric methods,photogrammetric densification
can now be carried out for points to be used for
photograinmetric or ground surveys. Control points used
tor ground surveys are usually monumented and normally
have coordinates of a higher standard of accuracy than
those of photogrammetric control. An estimate of the
accuracy of control coordinates is usually required.
The require~ent for high accuracy necessitates
carefully planning of the used equipment (i.e. camera,
comparator and computer) and the adjustment technique to
take full advantage of the high quality of the
photograrnmetric measurements.
To achieve a required accuracy optimally, an
a-priori investigation of a densification project
is necessary. This cou£d be done by applying
simulation to the variable parameters to obtain the
most economical and practical combination.
In this project, simulation data is created for an
area of 15km x 5.5. km to be covered by aerial
photography with a scale of 1:10,000. The simulation
data is extracted from a topograph~c m~p of a certain
area. This approach ensures the closeness of the
simulation data to the real environment.
The parameters selected for investigation are the
side lap, the number of·~easured points on each
photograph, and the number and configuration of the
ground control in the block.
More than 100 experiments were run using the
Bundle Adjustment technique. The values of the errors
are presented. The results obtained in each case could
be used to get an-insight into the achievable
·accuracies for a specific combination of the
parameters in executing aerial triangulation for a
project of the type handled in this research | en |
