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Uncertainties and errors in algorithms for elevation gradients / Dong Shi in International journal of geographical information science IJGIS, vol 35 n° 2 (February 2021)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 35 n° 2 (February 2021) . - pp 296 - 320 Titre : Uncertainties and errors in algorithms for elevation gradients Type de document : Article/Communication Auteurs : Dong Shi, Auteur ; Qinke Yang, Auteur ; Qifeng Zhu, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : pp 296 - 320 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] analyse comparative [Termes IGN] erreur [Termes IGN] filtrage du bruit [Termes IGN] fonction harmonique [Termes IGN] gradient d'altitude [Termes IGN] gradient de pente [Termes IGN] incertitude géométrique [Termes IGN] modèle numérique de surface [Termes IGN] modèle numérique de terrain Résumé : (auteur) Elevation gradients are primary components of slope and aspect. Significant concerns remain when computing gradients if noise (perturbing non-DEM data) is present. There is still a need to find ways to balance accuracy of the gradient and stability to noise for specific types of DEM. In this study, six algorithms are compared using four DEMs and analyzed for stability to base level DEM noise and added random noise. Theoretical stability and accuracy of the formulae are analyzed using harmonic (frequency or spatial scale) response. The results provide a basis to determine the most appropriate algorithm for different situations. They show that: (1) the set (Evans-Young (EY), Sharpnack (Sp), Sobel (Sb)) has a better stability to noise ratio than the set (Zevenbergen (Z), Florinsky (F), Horn (H)). EY has the smoothest surface and the highest stability to noise ratio. If stability is the primary measure in mid-frequencies, EY is a good choice. (2) Sb is good because of its accuracy in mid to high frequencies. Out to the highest frequencies, Sb is the best. (3) F has potential but should not be used with very high-frequency noise. (4) H and Z should not be used when there is substantial noise. Numéro de notice : A2021-039 Affiliation des auteurs : non IGN Thématique : IMAGERIE/INFORMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2020.1766047 Date de publication en ligne : 14/05/2020 En ligne : https://doi.org/10.1080/13658816.2020.1766047 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96748 [article]

Turgor – a limiting factor for radial growth in mature conifers along an elevational gradient / Richard L. Peters in New phytologist, vol 229 n° 1 (January 2021)  

Public [article]  inNew phytologist > vol 229 n° 1 (January 2021) . - pp 213 - 229 Titre : Turgor – a limiting factor for radial growth in mature conifers along an elevational gradient Type de document : Article/Communication Auteurs : Richard L. Peters, Auteur ; Kathy Steppe, Auteur ; Henri E. Cuny , Auteur ; Dirk J.W. de Pauw, Auteur ; David Frank, Auteur ; Marcus Schaub, Auteur ; Cyrille B.K. Rathgeber, Auteur ; Antoine Cabon, Auteur ; Patrick Fonti, Auteur Année de publication : 2021 Projets : 3-projet - voir note / Article en page(s) : pp 213 - 229 Note générale : bibliographie Funding information : COST Action network. Grant Number: STReESS/FP1106 -&- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung. Grant Numbers: CLIMWOOD/160077, Early Postdoc.Mobility/P2BSP3_184475, LOTFOR/150205 Langues : Anglais (eng) Descripteur : [Termes IGN] cerne [Termes IGN] changement climatique [Termes IGN] croissance des arbres [Termes IGN] gradient [Termes IGN] gradient de pente [Termes IGN] Larix decidua [Termes IGN] modèle de croissance végétale [Termes IGN] modèle de simulation [Termes IGN] Picea abies [Termes IGN] Pinophyta [Termes IGN] puits de carbone [Termes IGN] sécheresse [Vedettes matières IGN] Végétation et changement climatique Résumé : (auteur) A valid representation of intra‐annual wood formation processes in global vegetation models is vital for assessing climate change impacts on the forest carbon stock. Yet, wood formation is generally modelled with photosynthesis, despite mounting evidence that cambial activity is rather directly constrained by limiting environmental factors. Here, we apply a state‐of‐the‐art turgor‐driven growth model to simulate 4 yr of hourly stem radial increment from Picea abies (L.) Karst. and Larix decidua Mill. growing along an elevational gradient. For the first time, wood formation observations were used to validate weekly to annual stem radial increment simulations, while environmental measurements were used to assess the climatic constraints on turgor‐driven growth. Model simulations matched the observed timing and dynamics of wood formation. Using the detailed model outputs, we identified a strict environmental regulation on stem growth (air temperature > 2°C and soil water potential > −0.6 MPa). Warmer and drier summers reduced the growth rate as a result of turgor limitation despite warmer temperatures being favourable for cambial activity. These findings suggest that turgor is a central driver of the forest carbon sink and should be considered in next‐generation vegetation models, particularly in the context of global warming and increasing frequency of droughts. Numéro de notice : A2021-177 Affiliation des auteurs : IGN+Ext (2020- ) Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/nph.16872 Date de publication en ligne : 07/12/2020 En ligne : https://doi.org/10.1111/nph.16872 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96863 [article]

A method for drawing vertical curve in longitudinal profile in road project / Hüseyin İnce in Survey review, vol 51 n° 368 (September 2019)  

Public [article]  inSurvey review > vol 51 n° 368 (September 2019) . - pp 413 - 421 Titre : A method for drawing vertical curve in longitudinal profile in road project Type de document : Article/Communication Auteurs : Hüseyin İnce, Auteur ; Nuri Erdem, Auteur Année de publication : 2019 Article en page(s) : pp 413 - 421 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse numérique [Termes IGN] courbe [Termes IGN] échelle cartographique [Termes IGN] gradient de pente [Termes IGN] profil en long [Termes IGN] projet routier Résumé : (Auteur) In road projects, there is a difficulty in drawing tangent points of the calculated vertical curve, turning point and intermediate points due to horizontal and vertical scale differences. This problem is brought about by the fact that proportional relationship between the two different scales is not known for a length with a certain slope in longitudinal profile. This study proposes a method to eliminate this problem. It also gives an example and discusses the findings. Numéro de notice : A2019-367 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2018.1470071 Date de publication en ligne : 15/05/2018 En ligne : https://doi.org/10.1080/00396265.2018.1470071 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93473 [article]

An empirical evaluation of three elevation change symbolization methods along routes in bicycle maps / Annina Brügger in Cartography and Geographic Information Science, Vol 44 n° 5 (September 2017)  

Public [article]  inCartography and Geographic Information Science > Vol 44 n° 5 (September 2017) . - pp 436 - 451 Titre : An empirical evaluation of three elevation change symbolization methods along routes in bicycle maps Type de document : Article/Communication Auteurs : Annina Brügger, Auteur ; Sara Irina Fabrikant, Auteur ; Arzu Çöltekin, Auteur Année de publication : 2017 Article en page(s) : pp 436 - 451 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Rédaction cartographique [Termes IGN] bicyclette [Termes IGN] carte thématique [Termes IGN] gradient de pente [Termes IGN] itinéraire [Termes IGN] lecture de carte [Termes IGN] oculométrie [Termes IGN] pente [Termes IGN] sémiologie graphique Résumé : (Auteur) Elevation change is critical for choosing a route when bicycling. We detail an empirical study in which we comparatively evaluated three linear symbolization types (color hue, color-coded arrows, and elevation profiles) to depict elevation change in bicycle maps for two common bicycle route planning tasks: relative height detection and slope identification. Participants performed most accurately with the color-coded arrows for relative height detection tasks, whereas symbolization did not significantly influence map-use performance for slope identification. Participants preferred the elevation profile, in spite of their lowest performance with this method overall. Our rare empirical findings offer much needed new insights into the function and appropriateness of common elevation symbolization methods, specifically to identify elevation change in bicycle route planning tasks in urban areas where map display real estate is already very limited. Numéro de notice : A2017-450 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/15230406.2016.1193766 En ligne : http://dx.doi.org/10.1080/15230406.2016.1193766 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86361 [article]

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The protective effect of forests against rockfalls across the French Alps: Influence of forest diversity / S. Dupire in Forest ecology and management, vol 382 (15 December 2016)  

Public [article]  inForest ecology and management > vol 382 (15 December 2016) . - pp 269 - 279 Titre : The protective effect of forests against rockfalls across the French Alps: Influence of forest diversity Type de document : Article/Communication Auteurs : S. Dupire, Auteur ; Franck Bourrier, Auteur ; Jean-Matthieu Monnet, Auteur ; S. Bigot, Auteur ; Laurent Borgniet, Auteur ; Frédéric Berger, Auteur ; Thomas Curt, Auteur Année de publication : 2016 Article en page(s) : pp 269 - 279 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Alpes (France) [Termes IGN] biodiversité végétale [Termes IGN] composition floristique [Termes IGN] éboulement [Termes IGN] forêt alpestre [Termes IGN] gradient de pente [Termes IGN] longueur [Termes IGN] pente [Termes IGN] risque naturel [Termes IGN] service écosystémique [Vedettes matières IGN] Ecologie forestière Résumé : (auteur) The role of forests in the mitigation of natural hazards has been repeatedly demonstrated. The protective effect of mountain forests against rockfalls has especially been pointed out because it can constitute a natural and cost-effective protection measure in many situations. However, this particular ecosystem service may substantially differ according to the structure and the composition of the forest. Until now, the rockfall protection capability has always been studied at a local scale with only few forest types. Moreover, the comparison of the protective effect of the different forest types studied remains difficult because different methods and indicators were used. For the same reasons, it is not possible to draw conclusions about the influence of biological and structural diversities on the protection capabilities of forests from former works. The aims of this study were (1) to quantitatively assess the protective effect of forests at the French Alps scale and build a classification based on the protection capability, (2) to compare the protective effect of the different forest types present in the French Alps and (3) to analyze the relations between the protective effect and the forest diversity in terms of stand structure and tree composition. For this purpose, the model Rockyfor3D was used to simulate the propagation of rocks on 3886 different forest plots spread over the whole French Alps. Quantitative indicators characterizing the protective effect of each forest plot were then calculated from the simulation results and used to perform the different analyses. Our results emphasized the importance of taking into account the length of forest in the maximum slope direction for an accurate assessment of the protective effect. Thus, the minimum length of forest to get a reduction of 99% of the rockfall hazard was chosen as indicator to compare protective effect between forests. Using this indicator, half of the French Alpine forests presented a high level of protection after a short forested slope (190 m). A decreasing gradient in the protection capabilities was observed from forest types dominated by broadleaved species to those dominated by conifer species. Moreover, considering an equivalent proportion of conifers, stands dominated by shade-tolerant tree species showed better ability to reduce rockfall hazard. Finally, our study highlighted that a high biodiversity and a structural heterogeneity within the forest have a positive effect on the reduction of rockfalls hazard. Numéro de notice : A2016-766 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article DOI : 10.1016/j.foreco.2016.10.020 En ligne : http://dx.doi.org/10.1016/j.foreco.2016.10.020 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82405 [article]

Effects of micro-topographies on stand structure and tree species diversity in an old-growth evergreen broad-leaved forest, southwestern Japan / Tran Van Do in Global ecology and conservation, vol 4 (July 2015)  

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A linear indexing approach to mass movements susceptibility mapping. The case of the Chefchaouen province (Morocco) / Mohamed Mastere in Revue internationale de géomatique, vol 25 n° 2 (juin - août 2015)  

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Integration of remote sensing and GIS for evaluating soil erosion risk in northwestern Zhejiang, China / J. Huang in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 9 (September 2012)  

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Ray-traced slant factors for mitigating the tropospheric delay at the observation level / L. Urquhart in Journal of geodesy, vol 86 n° 2 (February 2012)  

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Image-based 3D surface reconstruction by combination of photometric, geometric, and real-aperture methods / Pablo d' Angelo in ISPRS Journal of photogrammetry and remote sensing, vol 63 n° 3 (May - June 2008)  

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An experiment using a circular neighborhood to calculate slope gradient from a DEM / X. Shi in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 2 (February 2007)  

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Groundwater assessment through an integrated approach using remote sensing, GIS and resistivity techniques: a case study from a hard rock terrain / P.K. Srivastava in International Journal of Remote Sensing IJRS, vol 27 n°18 - 19 - 20 (October 2006)  

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A multi-resolution approach for filtering LiDAR altimetry data / José L. Silvan-Cardenas in ISPRS Journal of photogrammetry and remote sensing, vol 61 n° 1 (October 2006)  

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Detecting major terrain parameters relating to mass movements' occurrence using GIS, remote sensing and statistical correlations, case study Lebanon / C. Abdallah in Remote sensing of environment, vol 99 n° 4 (15/12/2005)  

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Characterization of rainfall-induced landslides / F.C. Dai in International Journal of Remote Sensing IJRS, vol 24 n° 23 (December 2003)  

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