The quality of geodetic networks for guiding Tunnel Boring Machines (TBMs) inside long tunnels depends largely on the correct use of a gyroscope. These networks are based on a series of control points at the tunnel entrance, and link each station by means of survey observations as they advance along the tunnel. Once, the networks are used to guide the TBM, they are no longer checked again. It is necessary to perform high accuracy astronomical observations to stars in order to determine the gyrotheodolite constant. Since astronomical observations cannot be made inside tunnels, geodetic azimuths have to be used for the computations. However, these azimuths cannot theoretically be compared with the astronomical azimuths obtained by the gyrotheodolite. An alternative is to compute the instrument constant using the valúes of the deviation of the vertical derived from a geoid model. That is the approach used in this work where a methodology for the design of underground networks in long tunnels is also presented. This procedure has been implemented during the construction of the Guadarrama and Pajares high-speed railway tunnels (Spain).
This study was motivated by the need to improve densification of Global Horizontal Irradiance (GHI) observations, increasing the number of surface weather stations that observe it, using sensors with a sub-hour periodicity and examining the methods of spatial GHI estimation (by interpolation) with that periodicity in other locations. The aim of the present research project is to analyze the goodness of 15-minute GHI spatial estimations for five methods in the territory of Spain (three geo-statistical interpolation methods, one deterministic method and the HelioSat2 method, which is based on satellite images). The research concludes that, when the work area has adequate station density, the best method for estimating GHI every 15 min is Regression Kriging interpolation using GHI estimated from satellite images as one of the input variables. On the contrary, when station density is low, the best method is estimating GHI directly from satellite images. A comparison between the GHI observed by volunteer stations and the estimation model applied concludes that 67% of the volunteer stations analyzed present values within the margin of error (average of ±2 standard deviations).
Geographic information technologies (GIT) are essential to many fields of research, such as the preservation and dissemination of knowledge of cultural heritage buildings, a category which includes traditional underground wine cellars. This paper presents a methodology based on research carried out on this type of rural heritage building. The data were acquired using the following sensors: EDM, total station, close range photogrammetry and laser scanning, and subsequently processed with a specific software which was verified for each case, in order to obtain a satisfactory graphic representation of these underground wine cellars. Two key aspects of this work are the accuracy of the data processing and the visualisation of these traditional constructions. The methodology includes an application for geovisualising these traditional constructions on mobile devices in order to contribute to raising awareness of this unique heritage.
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