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This is a brief history of how a small group of people carried out its mandate to survey and map Canada in spite of the hostile environment — the second largest country in the world — in a 100 years.The levelling started from Halifax and by 1916 it reached Vancouver completing the coast-to-coast connection, encompassing about 22 000 km distance of which 94% was done on the railway tracks. The adjustment was carried out in 9 steps, it included the tide gauges in both the east and west coast, and was completed in 1928. The final adjustment used about 37 000 km length, from which 30 000 was measured by the GS. The first order re-levelling started after the Second World War and was carried out on the Trans-Canada highway. By 1994 Canada was covered by a levelling network of about 109 747 km. After this date there was no more conventional levelling.The triangulation used cross-braced quadrilaterals, based on the method used in the USA. In 1961 the GS started to use the conventional methods of chains of triangles. The measurements covered mostly the very southern part of Canada. The mapping of middle and northern part of the country had to await until the electronic era, which was practically made for Canada.The lower order accuracy was provided by Shoran, using about the average of 400 km line length for triangulation. Between 1947 and 1957 this method provided 501 measured triangle sides of about 200 000 km in total length and provided 119 base-point covering about 65% of Canada.The other method, the Aerodist — the Tellurometer version of Shoran — provided second order accuracy. The triangulation, using cross-braced quadrilaterals, with 100 km sides gave 219 points and covered about 25% of the land area of Canada. The measurements were done between 1965 and 1973.Recent measurements make use of GPS for geodetic position determination. A 10 year program started in 1987. In 1992 the GSD defined an official geoid to be used in connection with all satellite work.

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Several approaches have been made in the context of data assimilation in order to improve the estimates of electron density. The key point is to combine different types of data that offer complementary information, thus allowing to obtain a three dimensional description of the electronic content of the ionosphere. In this paper a data assimilation scheme will be proposed in which the complementarity of information will be given by the ground GPS data (horizontal variation) and vertical profiles  derived from ionosonde data (vertical variation). The results of this assimilation scheme will be verified by an external source of data, the GPS data gathered from receiver onboard GPSMET, a low earth orbiter at 750km. This comparison will show the feasability of this assimilation scheme. Moreover it will be shown how this method is able to provide with valuable information about the topside ionosphere by means of comparison with the vertical profiles retrieved from Radio Occultations using  Abel inversion. To do this  the approach of Abel inversion based on a separability hypothesis will be explained, and it will be compared with the classical approach that assumes spherical symmetry.

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Cereal Research Communications
Authors:
Tamás Németh
,
József Takács
,
Ferenc Simon
, and
Miklós Nádasy
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Nowadays, the Continuously Operating Reference Station (CORS) network, combined with network RTK corrections (NRTK solution), is a widely used technique for high-accuracy positioning in real time. This “active” network realizes a reference frame and propagates it to the users. In border regions the coherence between the reference frames propagated by neighboring active networks is a critical problem. In this study the test results of post-processed and simultaneous NRTK positions at six test points located in the border region between Portugal and the Community of Andalusia, in the south west of the Iberian Peninsula, are presented. The analysis is based on two GNSS active networks present in this border region, namely RENEP (Portugal) and RAP (Community of Andalusia, Spain), a national and a local RTK network respectively, with similar characteristics. Upon comparing the post-processed position for each test point, as estimated with respect to each of the two active networks analyzed, the discrepancies found in 3D were less than 2 centimeters. The results of network-based RTK positioning were found to be successful within a 2 cm precision level in the east and north components and 4 cm for the up component. The results also confirm that the NRTK positioning accuracy is about 2 cm in horizontal and 4 cm in vertical, which can satisfy the requirement of real-time positioning users at a centimetric accuracy level, even in border regions considering extrapolated NRTK solutions.

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The paper presents a photovoltaic system auto sizing algorithm with irradiance and shading calculation, which uses the photovoltaic geographical information system database. This calculation step is a very labor intensive task, which require a lot of iterative design time to find the optimum alternative. Based on measurement data, monthly irradiance correction matrixes are simulated to completely describe the yearly irradiance loss caused by shading of the nearby objects. As result, a function between the shaded area and the yearly energy loss can be obtained. Furthermore, photovoltaic modules can be auto-allocated on a given area according to the boundary conditions. Taking into consideration the photovoltaic installers’ pricing system, a complete photovoltaic auto-sizing algorithm can be presented, which greatly reduces the time spent on quotation writing. This paper also includes a battery energy storage sizing algorithm according to the given economic conditions, which extends the capability of the photovoltaic system auto-sizing algorithm.

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The goal of this study is to determine whether principal component analysis (PCA) can be used to process latitude-time ionospheric TEC data on a monthly basis to identify earthquake associated TEC anomalies earlier than 5 days before a large (M ≥ 6) earthquake. PCA is applied to latitude-time (mean-of-a-month) ionospheric total electron content (TEC) records collected from the Japan GEONET system to detect TEC anomalies associated with 26 earthquakes in Japan (M ≥ 6.0) from 2004 to 2005. According to the results, PCA was able to discriminate clear TEC anomalies in the months when all 26 earthquakes occurred. After reviewing months when no M ≥ 6.0 earthquakes occurred but geomagnetic storm activity was present, it is possible that the maximal principal eigenvalues PCA returned for these 26 earthquakes indicate earthquake associated TEC anomalies. Previously, PCA has been used to discriminate earthquake-associated TEC anomalies recognized by other researchers who found that statistical association between large earthquakes and TEC anomalies could be established in the 5 days before earthquake nucleation; however, since PCA uses the characteristics of principal eigenvalues to determine earthquake related TEC anomalies, it is possible to show that such anomalies existed earlier than this 5-day statistical window. In this paper, this is shown through the application of PCA to one-dimensional TEC data relating to the Kyushu earthquake of 20 March 2005 (M = 6.6). The analysis is applied to daily TEC and reveals a large principal eigenvalue (representative of an earthquake associated anomaly) for March 9, 11 days before the March 20 earthquake.

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The study presents the results of the survey conducted in the Sárvíz Valley as part of the international non-invasive topographic research project (“Workshop for Reading Past and Present Landscapes in Central Europe”), together with an overview of the new directions in survey methodology in Hungary and abroad, as well as their application.

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Orvosi Hetilap
Authors:
Szilvia Ádám
,
Péter Torzsa
,
Zsuzsa Győrffy
,
Krisztián Vörös
, and
László Kalabay

Hays, R., Wynd, S., Veitch, C. és mtsai: Getting the balance right? GPs who chose to stay in rural practice. Aust. J. Rural Health, 2003, 11 , 193–198. Veitch C. Getting the

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the training. Training load The players' physical activity during each training session was monitored using an athlete monitoring system with a 10-Hz GPS unit integrated with a 100-Hz

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A new quasi-geoid model for Hungary was determined by combining gravity data, GPS/levelling and vertical deflections. Reduction of the measurements was performed by using Earth Gravitational Model 2008 (EGM2008) and Shuttle Radar Topographic Mission (SRTM) elevation data sets. Calculation method was Least Squares Collocation (LSC) with self-consistent planar logarithmic covariance model. In the computations the weights of GPS/levelling data were large, in this way normal heights obtained from levelling are consistent with GPS heights and with the quasi-geoid model. Astrogeodetic-gravimetric, pure astrogeodetic and pure gravimetric solutions have been calculated besides the combined solution to investigate the discrepancies among the different models. The combined quasi-geoid model fits to the GPS/levelling data with standard deviation of ±4.9 cm, nevertheless at some GPS/levelling sites large differences were indicated.

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