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Ancyra project: The survey of the Augustus' temple in Ankara The Geodetic Survey A local geodetic network was established, composed by 11 theodolite points. Almost all the photographic control points have been signalised, taking advantage of the existing scaffoldings. The reached accuracy is rather high, less than one centimetre in the three co-ordinates. The used instrument was a Topcon GTP1002 total station. The computation and the adjustment of the co-ordinates was performed with RETE a least squares computed program (Fangi, 8, 1995), with least constraints. The final local co-ordinate system has been taken parallel to the eastern wall, the most complete and in better condition. 175 points, including 11 theodolite stations compose the network. In planimetry there are 496 observations, 259 angular equations, 243 measured distances, for a redundancy equal to 138 (relative redundancy 1.4). In altimetry the observations are 271, the unknowns 176 for a redundancy of 97, (relative redundancy 1.5). The obtained average for standard deviation both in plan and high are 0.5 cm, mainly due to the signalization of the control points. There is one argument to be remarked about the distances measured by the reflectorless EDM-theodolite: 18 over 245, i.e. 7% of the total, have been rejected because of incorrectness or disagreement with the other measurements. The cause for that is when the reflecting spot is not on a rather large and smooth surface, the obtained measure is not corrected. The operator must avoid to take distance form sharp points such as corners that can be observed only by angular readings. Apart this feature, the new reflectorless instruments have great advantage in terms of time, accuracy, but first of all, in terms of amount of necessary equipment, whose weight be greatly reduced, say more than 50%. In fact the connection among the points was not realised by the traditional traversing procedure, that is to connect the stations points by angular and range measurements. All the control points were observed, taking possibly the distances also. In this manner the station points can be easily and precisely established in the network; we could avoid to connect the stations by measurements of angles and distances. So the amount of equipment was greatly abridged compared with the traditional one. In fact three tripods, one total station, two tribranches and two prisms normally compose the traditional equipment. Only one tripod and one total station form now the required equipment with reflectorless instrument, say less than 50% of the first one, in terms of weight and number of pieces. The range of the distance-meter without prism is limited to hundred meters, more or less, depending very much on the reflecting surface. The range is then enough for the normal task of architectural survey. The internal recording of the measurements further speeds up the work. The efficiency of the survey is enhanced also by the freedom in choosing the station points, liberated from the constraint to be visible to each other. Finally, the possibility to get an uncorrected distance must lead to a particular large value of the redundancy. The type of instrument is then particularly suitable for archaeological missions where the weight and the volume of the equipment are a very limiting factor. In fig. 3 the lay-out of the control network. Finally, in order to be able to pass from one local system to another, we took care to determine also some control points of the previous photogrammetric survey, the epigraphs (Botteri,et al, 2, 1999).  Fig. 3 - The plan of the control network with the error ellipses The Photogrammetric Survey Almost all the photogrammetric control points were signalised by simple paper targets stuck on the scaffolding. The survey is then realised with horizontal stereo strips, taken from the scaffolding for the interior walls and from the pavement for the eastern wall. We used a semi-metric Rollei 6x6 camera and a non-metric camera Fuji Gsw69 large format camera.  Fig.4- Lay-out of the photogrammetric taking  Fig. 5 - The orthophotomosaic of the external Western Wall Tab.1- Main features of the photogrammetric photographs
The film was colour reversal Velvia Fuji 50ASA. The mean photo scale is about 1/200, allowing final plotting at scale 1/50. The existing scaffoldings have been useful for taking the photographs and for targeting, but on the other end hampered the total view al the wall. In fig. 4 the plan of the photogrammetric takings. The Photogrammetric Plotting At this moment the photogrammetric plotting is still going on. We use a Galileo-Siscam Stereometric-Pro digital station. All the photographs have been scanned with a calibrated Epson perfection 1200 Photo scanner, with a resolution of 1200 dpi, which seems to be enough good for our purposes. In fig. 5 an orthophomosaic of the western exterior wall is shown. Conclusions For the time being only some remarks about the surveying technique can be expressed. The new reflectorless theodolites enhance the efficiency of the survey, allowing the operator to get rid of the constraints of the visibility of any other measuring station. Finally, the possibility to get an uncorrected distance for certain type of points must lead to a particular large value for the redundancy and suggest to avoid determinations without redundancy. The type of instrument is then particularly suitable for archaeological missions where the weight and the volume of the equipment are a very limiting factor. References
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