Andrew U. Frank’s impact on research in land administration     

Gerhard Navratil 《International journal of geographical information science》2018,32(12):2501-2513

Andrew U. Frank retired in October 2016 after a scientific career of 38 years with positions in Switzerland, Maine and Austria. One of the main applications that he constantly referred to and that he analysed in detail was land administration. This review article tries to give an overview of Frank’s work in the context of land administration and how he influenced the approach to land administration research. He organized his work mainly in four pillars: technical, legal, organizational and economical aspects. Each of them is discussed in the paper and the influence on international cooperation is shown.  相似文献   

High-Pressure Melting of Eclogite and the P-T-X History of Tonalitic to Trondhjemitic Zoisite-Pegmatites, Munchberg Massif, Germany     

Liebscher  Axel; Franz  Gerhard; Frei  Dirk; Dulski  Peter 《Journal of Petrology》2007,48(5):1001-1019

Zoisite-bearing high-pressure pegmatites from the MünchbergMassif, Germany, provide an excellent example of the characteristicsof the onset of metabasite melting at eclogite-facies conditions.The pegmatites were derived by partial melting of a mid-oceanridge basalt (MORB)-like eclogite at T 680°C/2·3GPa to 750°C/3·1 GPa, which produced small amountsof tonalitic to trondhjemitic melt. The melt concentrated locallyin isolated, small melt pockets and crystallized primary zoisiteas liquidus phase at P 2·3 GPa/680°C to 2·1GPa/750°C. Compositional zoning of pegmatite zoisite recordsan ensuing multi-stage uplift history with successive, discretecrystallization events at 1·4 ± 0·2 GPa/650–700°Cand 1·0 ± 0·1 GPa/620–650°C.Resorption textures indicate reheating and thermal perturbationof the whole system prior to each successive crystallizationevent. Final solidification of zoisite-pegmatites occurred at0·9 ± 0·1 GPa/620–650°C. Thedata suggest that isolated melt + zoisite crystal mush pocketsformed an integral part of the eclogite throughout uplift frommelt formation at T 680°C/2·3 GPa to 750°C/3·1GPa to final solidification at 0·9 GPa/620–630°C;that is, over a depth range of 45–60 km. The entire pegmatite-formingprocess was probably fluid conserving: fluid present duringmelt formation was trapped by fully or nearly water-saturatedsiliceous melts, whereas fluid liberated during pegmatite crystallizationinteracted with dehydrated eclogite-facies assemblages to formamphibolite-facies hydrous minerals. A set of empirical D^{melt/eclogite}values based on mean zoisite-pegmatite and eclogite compositionwere used to model the onset of partial high-pressure meltingof metabasites. KEY WORDS: adakite; high-pressure melting; pegmatite; trondhjemite; zoisite  相似文献   

Robust and fast reconstruction of complex roofs with active sampling from 3D point clouds     

Youness Dehbi  Andr Henn  Gerhard Grger  Viktor Stroh  Lutz Plümer 《Transactions in GIS》2021,25(1):112-133

This article proposes a novel method for the 3D reconstruction of LoD2 buildings from LiDAR data. We propose an active sampling strategy which applies a cascade of filters focusing on promising samples at an early stage, thus avoiding the pitfalls of RANSAC‐based approaches. Filters are based on prior knowledge represented by (nonparametric) density distributions. In our approach samples are pairs of surflets—3D points together with normal vectors derived from a plane approximation of their neighborhood. Surflet pairs provide parameters for model candidates such as azimuth, inclination and ridge height, as well as parameters estimating internal precision and consistency. This provides a ranking of roof model candidates and leads to a small number of promising hypotheses. Building footprints are derived in a preprocessing step using machine learning methods, in particular support vector machines.  相似文献   

Determination of the Tin Stable Isotopic Composition in Tin‐bearing Metals and Minerals by MC‐ICP‐MS          下载免费PDF全文

Gerhard Brügmann  Daniel Berger  Ernst Pernicka 《Geostandards and Geoanalytical Research》2017,41(3):437-448

This study uses MC‐ICP‐MS for the precise analysis of the stable tin isotopic composition in ore minerals of tin (cassiterite, stannite), tin metal and tin bronze. The ultimate goal is to determine the provenance of tin in ancient metal objects. We document the isotope compositions of reference materials and compare the precision of different isotope ratios and the accuracy of different procedures of mass fractionation correction. These data represent a base with which isotopic data of future studies can be directly compared. The isotopic composition of cassiterite and stannite can be determined after reduction to tin metal and bronze, respectively. Both metals readily dissolve in HCl, but while the solutions of tin metal can be directly measured, the bronze solutions must be purified with an anion exchanger. The correction of the mass bias is best performed with an internal Sb standard and an empirical regression method. A series of Sn isotope determinations on commercially available mono‐element Sn solutions as well as reference bronze materials and tin minerals show fractionations ranging from about ?0.09‰ to 0.05‰/amu. The combined analytical uncertainty (2s) was determined by replicate dissolutions of reference materials of bronze (BAM 211, IARM‐91D) and averages at about 0.005‰/amu.  相似文献   

The celestial mechanics approach: theoretical foundations   总被引：4，自引：3，他引：1  

Gerhard Beutler  Adrian Jäggi  Leoš Mervart  Ulrich Meyer 《Journal of Geodesy》2010,84(10):605-624

Gravity field determination using the measurements of Global Positioning receivers onboard low Earth orbiters and inter-satellite measurements in a constellation of satellites is a generalized orbit determination problem involving all satellites of the constellation. The celestial mechanics approach (CMA) is comprehensive in the sense that it encompasses many different methods currently in use, in particular so-called short-arc methods, reduced-dynamic methods, and pure dynamic methods. The method is very flexible because the actual solution type may be selected just prior to the combination of the satellite-, arc- and technique-specific normal equation systems. It is thus possible to generate ensembles of substantially different solutions—essentially at the cost of generating one particular solution. The article outlines the general aspects of orbit and gravity field determination. Then the focus is put on the particularities of the CMA, in particular on the way to use accelerometer data and the statistical information associated with it.  相似文献   

The role of beach morphology on coastal cliff erosion under extreme waves          下载免费PDF全文

Claire Earlie  Gerhard Masselink  Paul Russell 《地球表面变化过程与地形》2018,43(6):1213-1228

Erosion of hard‐rock coastal cliffs is understood to be caused by a combination of both marine and sub‐aerial processes. Beach morphology, tidal elevation and significant wave heights, especially under extreme storm conditions, can lead to variability in wave energy flux to the cliff‐toe. Wave and water level measurements in the nearshore under energetic conditions are difficult to obtain and in situ observations are rare. Here we use monthly cliff‐face volume changes detected using terrestrial laser scanning alongside beach morphological changes and modelled nearshore hydrodynamics to examine how exposed cliffs respond to changes in extreme wave conditions and beach morphology. The measurements cover the North Atlantic storms of 2013 to 2014 and consider two exposed stretches of coastline (Porthleven and Godrevy, UK) with contrasting beach morphology fronting the cliffs; a flat dissipative sandy beach at Godrevy and a steep reflective gravel beach at Porthleven. Beach slope and the elevation of the beach–cliff junction were found to influence the frequency of cliff inundation and the power of wave–cliff impacts. Numerical modelling (XBeach‐G) showed that under highly energetic wave conditions, i.e. those that occurred in the North Atlantic during winter 2013–2014, with H_s = 5.5 m (dissipative site) and 8 m (reflective site), the combination of greater wave height and steeper beach at the reflective site led to amplified wave run‐up, subjecting these cliffs to waves over four times as powerful as those impacting the cliffs at the dissipative site (39 kWm^‐1 compared with 9 kWm^‐1). This study highlighted the sensitivity of cliff erosion to extreme wave conditions, where the majority (over 90% of the annual value) of cliff‐face erosion ensued during the winter. The significance of these short‐term erosion rates in the context of long‐term retreat illustrates the importance of incorporating short‐term beach and wave dynamics into geomorphological studies of coastal cliff change. © 2017 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.  相似文献   

Reaction of a polar gravel-spit system to atmospheric warming and glacier retreat as reflected by morphology and internal sediment geometries (South Shetland Islands,Antarctica)     

Pablo Heredia Barión  Sebastian Lindhorst  Ilona Schutter  Ulrike Falk  Gerhard Kuhn 《地球表面变化过程与地形》2019,44(5):1148-1162

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Beach cusp morphodynamics     

Gerhard Masselink  Bruce J. Hegge  Charitha B. Pattiaratchi 《地球表面变化过程与地形》1997,22(12):1139-1155

Detailed measurements of three-dimensional beach cusp morphology were made on a steep gradient, low energy, microtidal beach in Perth, Western Australia. During the field campaign a variety of wave conditions and tidal ranges were experienced, and these differing hydrodynamic conditions were reflected in a consistent pattern of morphological changes to the beach cusp system. A useful parameter to delineate between trends of cusp destruction and re-formation appeared to be the surf similarity parameter ξ = tan β/√I₀/L₀, where H₀ is offshore wave height, L₀ is deep water wave length and tan β is beach gradient. For ξ < 1·2 the beach cusps were planed off, whereas cusp morphology was enhanced when ξ > 1·2. A small storm was experienced at the start of the field campaign period and resulted in considerable erosion of the beach face. The cusp morphology across the lower beachface was destroyed, but a subtle remnant of the pre-storm cusp morphology was preserved on the upper beachface. When cusps reformed after the storm, under the influence of declining wave conditions, they appeared at the same location and with the same dimensions as the pre-storm cusp morphology. Hence, it is considered that the cusp re-formation was controlled more by the antecedent morphology than the hydrodynamic conditions. This indicates that positive feedback between swash hydrodynamics and beachface morphology, necessary to form beach cusps, does not require a large variation in relief. © 1997 John Wiley & Sons, Ltd.  相似文献   

The recent capture of the periodic comet P/Scotti (2000 Y3)     

Claes‐Ingvar Lagerkvist  Gerhard Hahn 《Astronomische Nachrichten》2001,322(4):265-267

Numerical integrations of 99 orbits centered on that of comet P/Scotti (P/2000 Y3), and of the nominal orbit, were made 4000 days backwards in time, and 73000 days into the future. The integrations show that this comet has been transferred into its present orbit as recently as 1998. The future orbital evolution indicates a stable period for almost 150 years, when another close encounter with Jupiter may lead to further drastic changes of the present orbit.  相似文献