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Title
New perspectives to save cultural heritage
Author
Altan, M. Orhan

C1PA 2003 XIX"' International Symposium, 30 September-04 October, 2003, Antalya, Turkey
271
- A monument, located at Praia Vermelha, Rio de
Janeiro, 2000, (PhotoModeler), see (2, Barbosa)
- Rock Art Photogrammetry - The Bear at Fonte
Grande II Canyon - Uibai, Bahia, Brazil, CIPA
2001,(PhotoModeler), see (10, Gilson D. Koatz)
3.2.2 Completion of Simplified Ground Control
However, in the case of large objects, one needs to
complete the simplified ground control by densification.
This can be done in different ways:
- by processing with software like ORPHEUS and
ORIENT of the Institute of Photogrammetry and Remote
Sensing , Vienna University of Technology, see (4,
Gomes: The Empress Manor-Project). An orthophoto of
the façade was produced by IDL-Software.
- by photogrammetric measurements;
Almost simultaneously to processing with ORPHEUS and
ORIENT in Vienna, the same stereopair of the
Empress Manor -Project with incomplete (poor) ground
control was introduced in the AVIOLYT BC 2 of
AEROFOTO CRUZEIRO S/A. In the relatively
orientated model about 33 points were measured.
Later on, the single model was adjusted by the
program PAT -M. Author: Hanns J.C. von Studnitz,
AEROFOTO CRUZEIRO S/A, Rio de Janeiro.
A digital restitution of the same façade was executed in
the Digital Video Plotter-DVP of IME.
- by additional topographic measurements.
In this case, one needs a coordinate system outside the
object system, the so-called
3.2.3 Arbitrary local coordinate system
Origin :
X = 1000.000
Y = 500.000
Z= 100.000
Figure 2 - Definition of the two coordinate systems
3.3 Topographic Measurements
3.3.1 Polar measurements by use of a Total Station
Initially it was planned to use a Total Station LEICA TCR
307 in reflector-less mode with simultaneous
trigonometric levelling from a baseline of two stations in
order to determinate polar coordinates of control points.
But it turned out that due to very oblique pointings, the
return signal to EDM was too weak and thus the distance
measurements failed in about of 40 % of instances.
Therefore we decided to use the intersection method for
all points of the project and to consider the polar
coordinates for comparison purposes only.
3.3.2 Forward intersection
The spatial coordinates to a total of 42 points (mostly
targets) were determined by forward intersection in the x-
y-plane with simultaneous trigonometric levelling. In the
beginning from two stations in the arbitrary system, in
later stages from three stations directly in the object
system (see 3.6.2).
For safety reasons we strongly recommend a double
forward intersection using two baselines, for example B-
A and B-C, (see figure 3).
Figure 3 - Double Forward Intersection
3.3.3 Comparison between polar and intersection
method
Coordinate differences for 15 determinations were
compared and showed the following standard deviations:
± 6.61 mm in x-coordinates (1 point out of
tolerance)
± 8.26 mm in y-coordinates (2 points out of
tolerance)
3.4 Computations
The spatial coordinates ( x,y,z ) were computed by use of
a program developed based on manual calculations for
plane forward intersection combined with trigonometric
levelling by the author Walter da Silva Prado, (see
fig. 4).