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Are prominent mountains frequently mentioned in text? Exploring the spatial expressiveness of text frequency / Curdin Derungs in International journal of geographical information science IJGIS, vol 32 n° 5-6 (May - June 2018)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 32 n° 5-6 (May - June 2018) . - pp 856 - 873 Titre : Are prominent mountains frequently mentioned in text? Exploring the spatial expressiveness of text frequency Type de document : Article/Communication Auteurs : Curdin Derungs, Auteur ; Tanja Samardžić, Auteur Année de publication : 2018 Article en page(s) : pp 856 - 873 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Toponymie [Termes IGN] Alpes centrales [Termes IGN] échelle géographique [Termes IGN] géomorphologie [Termes IGN] recherche d'information géographique [Termes IGN] Suisse [Termes IGN] toponyme [Termes IGN] traitement du langage naturel Résumé : (Auteur) Data-driven GIScience shows a growing interest in making spatial information from large text data. In this paper, we quantify and thus evaluate the relation between text frequency and properties of the outer-text, geographic setting by comparing text frequencies of mountain names to the respective geomorphometric characteristics. We focus on some 2000 unique mountain names that appear some 50,000 times in a large compilation of texts on Swiss alpine history. The results on the full data set suggest only a weak relation: only 5–10% of the variation in the text frequency being explained by the respective geomorphometric characteristics. However, an analysis of multiple scales allows us to identify a Simpson’s Paradox. What appears to be ‘noise’ in the analysis of all mountains in the whole of Switzerland shows significant local signals. Small spatial extents, found all over Switzerland, can show considerably strong correlations between text frequency and spatial prominence, with up to 90% of the total variation explained. We argue that our findings have practical implications for data-driven GIScience. Retrieving meaningful spatial information from text might only be possible if the spatial scale of analysis reflects the spatial scale described in the input text documents. Numéro de notice : A2018-194 Affiliation des auteurs : non IGN Thématique : TOPONYMIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2017.1418362 Date de publication en ligne : 26/12/2017 En ligne : https://doi.org/10.1080/13658816.2017.1418362 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89859 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2018031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Monitoring rock glaciers by combining photogrammetric and GNSS-based methods / Fabian Neyer (2017)  

Public Titre : Monitoring rock glaciers by combining photogrammetric and GNSS-based methods Type de document : Thèse/HDR Auteurs : Fabian Neyer, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2017 Autre Editeur : Zurich : Eidgenossische Technische Hochschule ETH - Ecole Polytechnique Fédérale de Zurich EPFZ Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 99 Importance : 174 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-45-1 Note générale : bibliographie thesis submitted to attain the degree of doctor of sciences of ETH Zurich Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] Alpes centrales [Termes IGN] champ de vitesse [Termes IGN] collocation par moindres carrés [Termes IGN] déformation de la croute terrestre [Termes IGN] données localisées 3D [Termes IGN] glacier [Termes IGN] image terrestre [Termes IGN] matrice de covariance [Termes IGN] pergélisol [Termes IGN] reconstruction 3D [Termes IGN] rocher [Termes IGN] série temporelle [Termes IGN] Suisse Index. décimale : 30.60 Géodésie spatiale Résumé : (auteur) Rock glaciers are creeping landforms of perennially frozen ground and belong to the permafrost creeping phenomena. They are mainly composed of rock debris that accumulate in areas of high natural erosion. Ice particles between the rocks cause the moving accumulation in steep terrain to dynamically flow downslope. In the Alpine region, these morphological landforms mainly occur at north-facing mountain slopes in high altitudes above the forest boundary and are known for their sensitivity to climate change. For several decades, rock glaciers have been monitored for scientific aims, while advances in surveying technologies increased the interest in such studies since the 1990s. Modern technologies in remote sensing (e.g., airborne imagery or satellite-based measurement techniques) are often combined with measurements from field campaigns, i.e., measurements taken directly on a rock glacier (e.g., GNSS, laser-scanning, ground temperature measurements, etc). The high-level goal is to enhance the process understanding, especially with respect to the changing climate: various studies indicate an extended risk of slope failures in steep frozen bedrock due to the global temperature increase. Early recognition of increased activities help to inform local authorities in the endangered areas about the potential hazard before such an event. The present work is part of the X-Sense project (Nano-Tera.ch), with an interdisciplinary team of scientists that build and operate new low-cost devices for data acquisition, develop new data processing pipelines and algorithms for evaluation, and also gain new insight of natural processes in these regions. Autonomous measurement systems, developed within other work packages in the X-Sense project, observe different permafrost creep areas with high resolution in space and time. Combined with multi-year observations, the derived surface motions are used to obtain an improved process understanding. This work focuses on the photogrammetric image processing in order to retrieve precise surface displacement estimates. More precisely, image sequences, acquired with two permanently installed commercial digital single-reflex cameras, are used to measure topographic changes in the observed permafrost area. By the combination with high resolution GNSS positioning results, the goal is to obtain precise time series of moving rock boulders at different positions within the field of view. Challenges arising from the combination of different data sets, the development of an automatic processing pipeline, and an improvement of the processing strategy in general, are the main tasks of this thesis. The study site is the bordering area above the Grabengufer rock glacier (Mattervalley VS, Switzerland), known as the Grabengufer rock slide. Local topographic conditions allowed only a partially good installation geometry for the photogrammetric reconstruction. With respect to a 3D reconstruction without the use of GNSS coordinates, an accuracy increase of about one order of magnitude could be achieved in case these high-precision solutions were integrated. More specifically, respective standard deviations for the East, North, and Height components of 6, 5, and 2 cm were achieved. The stated accuracy, maintained throughout the measurement period of nearly four years (summer months), was obtained in an area of approximately 80m×80 m, with a mean distance of 80 m from the two cameras. Position time series of moving rock boulders were filtered using the principles of collocation. Analyzing the correlation characteristics of the stochastic signal, an optimal correlation length was computed and used to extract relevant signals from the noise contaminated time series. Velocity was directly estimated as a derived quantity in the collocation process. Furthermore, the techniques of the adaptive collocation approach is presented. This iterative method uses the principles of a dynamically adjusting anisotropic covariance metric. In an example of 2-dimensional velocity fields it is shown that regional compression and extension areas can be extracted. Results indicate that the observed permafrost area has experienced a mean annual acceleration of about 0.1m/Year between the years 2013 and 2015. During the late summer months of 2015, a prominent temporal acceleration was observed. The mean displacement rate was found to be 0.67m/year, whereas the 3-dimensional displacement is dominated by a translation following the gliding surface. An area in the front of the observed field of view was found to have higher displacement rates, especially during the late summer months, thus it detaches from the otherwise relatively homogeneous flow field. The methods and principles presented in this work show the potential of monitoring permafrost surface displacements using permanently installed optical cameras in combination with positioning results from permanently mounted GNSS stations. These principles can easily be transfered to other monitoring applications and thus contribute to a better understanding of such processes. Note de contenu : 1 Introduction 2 Study Site 3 Image-Based Displacement Estimation 4 Object Point Reconstruction 5 Collocation for Time Series Analysis 6 Results 7 Conclusions 8 Outlook Numéro de notice : 17458 Affiliation des auteurs : non IGN Autre URL associée : https://doi.org/10.3929/ethz-a-010865360 Thématique : IMAGERIE Nature : Thèse étrangère Note de thèse : thèse : Sciences : ETHZ : 2016 DOI : 10.3929/ethz-a-010865360 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-99.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89683

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
17458-01	33.60	Livre	Centre de documentation	Photogrammétrie - Lasergrammétrie	Disponible

Image based geo-localization in the Alps / Olivier Saurer in International journal of computer vision, vol 116 n° 3 (February 2016)  

Public [article]  inInternational journal of computer vision > vol 116 n° 3 (February 2016) . - pp 213 - 225 Titre : Image based geo-localization in the Alps Type de document : Article/Communication Auteurs : Olivier Saurer, Auteur ; Georges Baatz, Auteur ; Kevin Köser, Auteur Année de publication : 2016 Article en page(s) : pp 213 - 225 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] Alpes centrales [Termes IGN] analyse visuelle [Termes IGN] données GPS [Termes IGN] exploration de données géographiques [Termes IGN] image 2D [Termes IGN] modèle numérique de surface [Termes IGN] modèle numérique de terrain [Termes IGN] reconnaissance automatique [Termes IGN] Suisse Résumé : (Auteur) Given a picture taken somewhere in the world, automatic geo-localization of such an image is an extremely useful task especially for historical and forensic sciences, documentation purposes, organization of the world’s photographs and intelligence applications. While tremendous progress has been made over the last years in visual location recognition within a single city, localization in natural environments is much more difficult, since vegetation, illumination, seasonal changes make appearance-only approaches impractical. In this work, we target mountainous terrain and use digital elevation models to extract representations for fast visual database lookup. We propose an automated approach for very large scale visual localization that can efficiently exploit visual information (contours) and geometric constraints (consistent orientation) at the same time. We validate the system at the scale of Switzerland (40,000 km2) using over 1000 landscape query images with ground truth GPS position. Numéro de notice : A2016--139 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1007%2Fs11263-015-0830-0 En ligne : https://doi.org/10.1007/s11263-015-0830-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85867 [article]

High resolution DEM generation in high-alpine terrain using airborne remote sensing techniques / Y. Bühler in Transactions in GIS, vol 16 n° 5 (October 2012)  

Public [article]  inTransactions in GIS > vol 16 n° 5 (October 2012) . - pp 635 - 647 Titre : High resolution DEM generation in high-alpine terrain using airborne remote sensing techniques Type de document : Article/Communication Auteurs : Y. Bühler, Auteur ; M. Marty, Auteur ; C. Ginzler, Auteur Année de publication : 2012 Article en page(s) : pp 635 - 647 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] Alpes centrales [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] modèle numérique de surface [Termes IGN] Suisse Résumé : (Auteur) Up-to-date and accurate digital elevation models (DEMs) are essential for many applications such as numerical modeling of mass movements or mapping of terrain changes. Today the Federal Department of Topography, swisstopo, provides Digital Terrain Models (DTMs) and Digital Surface Models (DSMs) derived from airborne LiDAR data with a high spatial resolution of 2 m covering the entire area of Switzerland below an elevation of 2000 m a.s.l.. However, above an elevation of 2000 m a.s.l., which is typical for high-alpine terrain, the best product available is the a DTM with a spatial resolution of 25 m. This spatial resolution is insufficient for many applications in complex terrain. In this study, we investigate the quality of DSMs derived from opto-electronic scanner data (ADS80; acquired in autumn 2010) using photogrammetric image correlation techniques based on the multispectral nadir and backward looking sensor data. As reference, we take a high precision airborne LiDAR data set with a spatial resolution of ca. 0.5 m, acquired in late summer 2010, covering the Grabengufer/Dorfbach catchment near Randa, VS. We find the deviations between the two datasets are surprisingly low. In terrain with inclination angles of less than 30° the RMSE is below 0.5 m. In extremely steep terrain of more than 50° the RMSE goes up to 2 m and outliers increase significantly. We also find dependencies of the deviations on illumination conditions and ground cover classes. Finally we discuss advantages and disadvantages of the different data acquisition methods. Numéro de notice : A2012-515 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/j.1467-9671.2012.01331.x Date de publication en ligne : 20/08/2012 En ligne : https://doi.org/10.1111/j.1467-9671.2012.01331.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31961 [article]

Better weather prediction using GPS: water vapor tomography in the Swiss Alps / Simon Lutz in GPS world, vol 21 n° 7 (July 2010)

Public [article]  inGPS world > vol 21 n° 7 (July 2010) . - pp 40 - 47 Titre : Better weather prediction using GPS: water vapor tomography in the Swiss Alps Type de document : Article/Communication Auteurs : Simon Lutz, Auteur ; Donat Perler, Auteur ; Marc Troller, Auteur ; et al., Auteur Année de publication : 2010 Article en page(s) : pp 40 - 47 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] affaiblissement de la précision [Termes IGN] Alpes centrales [Termes IGN] atténuation du signal [Termes IGN] humidité de l'air [Termes IGN] prévision météorologique [Termes IGN] Suisse [Termes IGN] teneur en vapeur d'eau [Termes IGN] tomographie [Termes IGN] traitement du signal Résumé : (Editeur) [...] Forecasting ability has improved as measurement technology, communications, and the understanding of atmospheric processes have improved. Meteorologists use measure- ments from various types of sensors and mathematical models to predict its future state. Yet better sampling of the current state of the atmosphere, particularly water vapor, is needed to produce more accurate and more timely forecasts. GPS can help. The signals from the GPS satellites must transit the atmosphere on their way to a receiver on the Earth's surface. The atmosphere's atoms and molecules slow down the signals so that they arrive slightly later than they would if the Earth was surrounded by a vacuum, and this effect shows up in the GPS receiver measurements. The receiver or measurement processing software needs to remove or model the effect to obtain accurate receiver positions. On the other hand, if all parameters affecting GPS measurements such as satellite and receiver coordinates are well known, then the delay imparted by the atmosphere can be estimated. It is possible to separate the effect of water vapor from that of the dry gases such as nitrogen, oxygen, and carbon dioxide and to provide a measure of the atmosphere's moisture content. Several national weather agencies are ingesting such estimates from networks of GPS receivers into experimental or operational numerical weather forecast models. But these values represent an integrated measure of moisture above a receiver. Profiles of how moisture is distributed with height would be more useful and might lead to better weather forecasts. In this month's column, a team of Swiss researchers discuss how they use data from a network of GPS receivers and the technique of tomography to obtain such profiles. Numéro de notice : A2010-271 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30465 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
067-2010071	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Prediction of vertical deflections from high-degree spherical harmonic synthesis and residual terrain model data / C. Hirt in Journal of geodesy, vol 84 n° 3 (March 2010)  

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Effects of atmospheric and climate change at the timberline of the Central European Alps / Gerhard Wieser in Annals of Forest Science, Vol 66 n° 4 (June 2009)  

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Dictionnaire encyclopédique des Alpes, 1. Volume 1 / P. Kober (2006)

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ALGESTAR, satellitengestützte Geoidbestimmung in der Schweiz mit GPS / Urs Marti (1990)  

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Entfernungsmessungen des Instituts für Astronomische und Physikalische Geodäsie der Technischen Hochschule München im Jahre 1966 / K. Deichl (1967)

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Les Alpes occidentales : les grandes Alpes francaises du nord (massifs centraux, zone intra-alpine), Tome 3. Partie 1 / Raoul Blanchard (1943)

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Les Alpes occidentales : les grandes Alpes francaises du nord (massifs centraux, zone intra-alpine), Tome 3. Partie 2 / Raoul Blanchard (1943)

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Les Alpes et les grandes ascensions / E. Levasseur (1888)

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