Strip and block adjustments in aerial triangulation
Abstract
The adjustment of aerial triangulation has been a
subject of serious study since aerial triangulation was
introducedo In recent years the usage of sophisticated
computers has greatly advanced the techniques of
adjustments.
Many survey departments carry out aerial triangulation
for mapping purposes only. Thus when adjustments are
applied and accuracies specified, they are related to
mapping at various scales. In this thesis, the author
carried out aerial triangulation by independent models
on wild A8. The original purpose for the photography
was mapping for cadastral purposes at the scale of 1/2500.
The photography covers an agricultural area.
The author has concentrated on the problem of
transformation of machine strip coordinates into the
ground system, and the subsequent adjustments. Some
transformation and adjustment methods which had been
recommended by L.P. Adams (10) have been modified.
The relationship between long and short strips were
investigated and the usefulness of Helmert's
Transformation in-strip and Block transformation was
investigated. An attempt was also made in the
transformation of plan and height values simultaneouslyo
This transformation was done on _an ICL 1900 computer, but
all the other computations were done on Hewlett Packard
Calculator.
The author has also introduced and indicated the
possibilities of using distribution-free statistical
analysis. All the recommendations and conclusions
arrived at are directed to the)prOblems of adjustment
of aerial triangulation for mapping purposes, The data
used consisted of the following:
Block •••••••••••••••• Mathira, Ndia, South Tetu (Kenya)
Contract ••••••••••••• 65.24
Purposes ••••••••••••• Cadastral Mapping
Scale of Photography ••••• 1/12,500
Organization •••••••••••••• Survey of Kenya
Date ••••••••••••••••• 1965
Flying Height ••••••• 7,500 ft. above Terrain
)Camera •••••••••••••• Wild R.C. 8
Lens •••••••••••••••• Wild Aviogon F. 5.6
Calibrated Principal Distance ••••• 152.06 mm
Fore and A~ Overlap ••••••••••• 60%
Lateral Overlap •••••••••••••••• 28%
Navigatio~ and Stabilisation •••••••••• Nil
-Auxiliary Instruments •••••••••••••••• Nil
Number of Strips ••••••••••••••••••••• 4 (4, 5, 6, 7)
Average Number of Models •••••••••••••• 19
Although the purpose of mapping was for cadastral
mapping, the survey is only tertiary and fourth order
in accuracy_ It is supposed to provide base maps for
land adjudication and consolidation, and also to
provide Registry Index Maps, which indicate consolidated
plot boundaries at scales of 1/2500. here Registry Index
Maps are required, contours are not necessary and heights
should be only sufficiently accurate to ensure adequate
levelling of the stereo models. Topographic mapping is
also done from such photography.
The problem should therefore be considered as
restricted to small section cadastral mapping to provide
land titles to land owners. The computational problems
should as well be considered as those of a small survey
office, hence the extensive use of small desk computers.
Citation
Degree of Master of Science in the University of NairobiPublisher
University of Nairobi Institute for Development Studies
Description
A Thesis submitted in part fullfilment for the Degree
of Master of Science in the University of Nairobi