Preparing digital documentation of historical buildings is a form of protecting cultural heritage. Recently there have been several intensive studies using non-metric digital images to construct realistic 3D models of historical buildings. Increasingly often, non-metric digital images are obtained with unmanned aerial vehicles (UAV). Technologies and methods of UAV flights are quite different from traditional photogrammetric approaches. The lack of technical guidelines for using drones inhibits the process of implementing new methods of data acquisition.
This paper presents the results of experiments in the use of digital images in the construction of photo-realistic 3D model of a historical building (Raphaelsohns’ Sawmill in Olsztyn). The aim of the study at the first stage was to determine the meteorological and technical conditions for the acquisition of aerial and ground-based photographs. At the next stage, the technology of 3D modelling was developed using only ground-based or only aerial non-metric digital images. At the last stage of the study, an experiment was conducted to assess the possibility of 3D modelling with the comprehensive use of aerial (UAV) and ground-based digital photographs in terms of their labour intensity and precision of development. Data integration and automatic photo-realistic 3D construction of the models was done with Pix4Dmapper and Agisoft PhotoScan software Analyses have shown that when certain parameters established in an experiment are kept, the process of developing the stock-taking documentation for a historical building moves from the standards of analogue to digital technology with considerably reduced cost.
In computational tasks of satellite geodesy there is a need for transformation of coordinates between reference frames ECEF – Earth Centered, Earth Fixed and ECI – Earth Centered, Inertial. Strict and simplified transformation models, which can be used in case of the position and velocity short-term predictions of GLONASS satellites, have been presented in this study. Comparison of the results of state vector components predictions of the GLONASS satellites, in dependence of the used transformation model, have also been presented. Accuracy of the prediction has been determined on the basis of the analyse of deviations of the predicted positions and velocities of GLONASS satellites from their values given in broadcast ephemeris.
Modernization of the land and buildings cadastre is a set of actions aimed at improving the quality of data collected there. Application in the process of modernization of the sources of information from the land surveying, gives fully satisfactory results. On the other hand the use of photogrammetric measurements is the solution more economical in terms of financial and time. However, there is a danger of obtaining the results which do not meet the standards of accuracy of the border points position. The paper presents an example of the results of the influence of the process of modernizing the land and buildings cadastre for the areas where the source material are cadastral maps in the scale 1: 2000, created on the basis of photomaps or cadastral maps in the scale 1: 2880. An assessment of the suitability of these materials in the process of modernization and their impact on the current form of the land and building cadastre as a public register was made.
This paper investigates information potential contained in tropospheric delay product for selected International GNSS Service (IGS) stations in climatologic research. Long time series of daily averaged Integrated Precipitable Water (IPW) can serve as climate indicator. The seasonal model of IPW change has been adjusted to the multi-year series (by the least square method). Author applied two modes: sinusoidal and composite (two or more oscillations). Even simple sinusoidal seasonal model (of daily IPW values series) clearly represents diversity of world climates. Residuals in periods from 10 up to 17 years are searched for some long-term IPW trend – self-evident climate change indicator. Results are ambiguous: for some stations or periods IPW trends are quite clear, the following years (or the other station) not visible. Method of fitting linear trend to IPW series does not influence considerably the value of linear trend. The results are mostly influenced by series length, completeness and data (e.g. meteorological) quality. The longer and more homogenous IPW series, the better chance to estimate the magnitude of climatologic IPW changes.
This paper analyzes selected aspects of the use of video-tacheometric technology for inventorying and documenting geometric features of objects. Data was collected with the use of the video-tacheometer Topcon Image Station IS-3 and the professional camera Canon EOS 5D Mark II. During the field work and the development of data the following experiments have been performed: multiple determination of the camera interior orientation parameters and distortion parameters of five lenses with different focal lengths, reflectorless measurements of profiles for the elevation and inventory of decorative surface wall of the building of Warsaw Ballet School. During the research the process of acquiring and integrating video-tacheometric data was analysed as well as the process of combining “point cloud” acquired by using video-tacheometer in the scanning process with independent photographs taken by a digital camera. On the basis of tests performed, utility of the use of video-tacheometric technology in geodetic surveys of geometrical features of buildings has been established.
The common aim of engineering surveys is to determine deviations from rectilinearity for elongated objects. We have developed a number of methods for measuring points that represent an elongated object. These are the constant straight (optical, laser, mechanical-string) method, the trigonometric method, geometric levelling method, photogrammetric methods and terrestrial laser scanning. When taking these measurements, it is crucial to have a direct access to the survey points of the measured object. Factors impeding the measurements include: adverse lighting conditions, vibration, dust, refractory effects, lack of direct access to the survey points, etc.
The authors have developed a measurement methodology and designed a measuring set for taking measurements that enable to determine the location of survey points on an elongated object.
The measurement is based on the constant straight method and the measuring set consists of the horizontal levelling staff and two laser pointers. The measuring set relies on the angular intersection (fixed angle) method. Intersection occurs when two laser beams meet. To determine the location of the survey point indicated by the mentioned laser beams, we used levelling staff readings taken with the surveying instrument that establishes the reference constant straight.
Experimental studies carried out in the laboratory and in the field helped to determine the accuracy of measurements taken with the designed measuring set (the accuracy was below ± 1 mm) and revealed that this accuracy is comparable to accuracies achieved with famous classical measurement methods.
The correctness of the geodetic service of an engineering object not seldom requires designing, alignment or renewing of geodetic situational control points. Building robots often cause that fixed situational control points are partly or completely inaccessible. For setting the position of these control points, there is worked out the methodology using the optoelectronic method. The prepared set of tools realizes the method’s assumptions and enables to determine the sides and control points based on the set of laser planes. In this article there is presented the innovative set of geodetic equipment for fixing horizontal control points. The presented set has been experimentally tested under laboratory conditions taking its functionality, operation range and applied accuracy into account. The measurement accuracy of the set of tools, resulting from identification of the energetic centres of laser planes’ edges, visualizing the sides of geodetic control networks, is within the range of ±0.02mm - ±0.05mm. There were also discussed exemplary versions of shapes and structures of horizontal geodetic control networks (regular and irregular), which are possible to be fixed with the use of the constructed set of tools.
In studies of movement essential element of the correctness of the obtained results is correct identification of the reference base. One method for such identification, referred to as “all-pairs method”, is to examine the insignificance of the mutual displacement of potential reference points in all combinations of pairs. It is a well known exact method of identification, but its use in practice is limited to the study of vertical displacements. In this work we present the possibility of application of this method in the study of horizontal displacements. Numerical example illustrates the calculation procedure of the proposed method.
We present results of the comparison of integrated precipitable water measurements from GPS solution and aerological techniques: CIMEL-318 sun-photometer and radiosoundings (RAOB). Integrated Precipitable Water (IPW) - important meteorological parameter is derived from GPS tropospheric solutions by known procedure for GPS station at Polish Polar Station, Hornsund (Svalbard). The relation between 2 m temperature and the mean temperature of atmosphere above, used to convert from wet part of tropospheric delay (ZWD) to IPW, has been derived using local radiosonde data at Ny Alesund. Sunphotometer data have been provided by AERONET. Quality of dedicated tropospheric solutions has been verified by comparison with EPN tropospheric combined product. Several IPW comparisons and analyses lead to determination of systematic difference between techniques: GPS IPW and sunphotometer data (not present in case of RAOBs). IPW measured by CIMEL is on average 5% bigger (0.5 mm) than IPW from GPS. This bias changes seasonally and is a function of atmospheric temperature what signals some systematic deficiencies in solar photometry as IPW retrieval technique. CIMEL IPW show some temperature dependent bias also in relation to radiosoundings.
The article presents the basic rules for constructing and training neural networks called the Support Vector Machine method as well as possible applications for this kind of network. SVM networks are mainly used for solving tasks of classifying linearly and non-linearly separable data and regression. However, in recent years more applications have been found for them. The networks also solve such problems as the recognition of signals and images as well as speech identification.
In this paper, non-linear SVM networks have been used for classifying linearly separable and non-separable data with a view to formulating a model of displacements of points in a measurement-control network. The points of the measurement-control network were placed on a civil engineering object located on expansive soil (linearly separable data) and represented a mining exploitation area (linearly non-separable data). The task of training SVM networks requires the use of quadratic programming in search of an optimum point of the Lagrangian function in relation to the parameters being optimised. In the case of linearly non-separable data, the SVM method makes it possible to find a hyperplane which classifies objects as correctly as possible, and at the same time is located possibly far away from concentrations typical of each class.