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Robust high-quality interpolation of regions to moving regions / Florian Heinz in Geoinformatica, vol 20 n° 3 (July - September 2016)
[article]
Titre : Robust high-quality interpolation of regions to moving regions Type de document : Article/Communication Auteurs : Florian Heinz, Auteur ; Ralf Hartmut Güting, Auteur Année de publication : 2016 Article en page(s) : pp 385 – 413 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] analyse spatio-temporelle
[Termes IGN] base de données orientée objet
[Termes IGN] données spatiotemporelles
[Termes IGN] implémentation (informatique)
[Termes IGN] interpolation linéaire
[Termes IGN] méthode robuste
[Termes IGN] objet mobile
[Termes IGN] représentation du changementRésumé : (auteur) With the rise of moving object databases it is possible to store and process spatial and temporal data, for example geometrical structures together with the information about how these behave over intervals of time. For simple objects like moving points the spatiotemporal development is derived from the start and end position in space and time, which is then linearly interpolated. For moving regions, especially with changing shapes, it is more challenging to obtain the necessary data to represent them. An elegant and intuitive solution is to create an algorithm, which automatically interpolates the moving region from the start and end shape over a specified time interval. Two papers on this topic have been published in the past, each focussing on different aspects of this so-called Region Interpolation Problem. This paper tries to combine the advantages and improve these approaches to provide high-quality interpolations while maintaining robustness even in border cases. This results in the implementation of a library, which can be easily integrated into existing moving objects database systems, as for example the DBMS Secondo developed at the FernUniversität in Hagen. Numéro de notice : A2016-376 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-015-0240-z Date de publication en ligne : 12/11/2015 En ligne : https://doi.org/https://doi.org/10.1007/s10707-015-0240-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81143
in Geoinformatica > vol 20 n° 3 (July - September 2016) . - pp 385 – 413[article]Comparison of robust estimators for leveling networks in Monte Carlo simulations / Maria Pokarowska in Reports on geodesy and geoinformatics, vol 101 (June 2016)
[article]
Titre : Comparison of robust estimators for leveling networks in Monte Carlo simulations Type de document : Article/Communication Auteurs : Maria Pokarowska, Auteur Année de publication : 2016 Article en page(s) : pp 70 - 81 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Nivellement
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] méthode des moindres carrés
[Termes IGN] méthode robuste
[Termes IGN] réseau de nivellement
[Termes IGN] valeur aberranteRésumé : (Auteur) We compared the method of least squares (LS), Pope’s iterative data snooping (IDS) and Huber’s M-estimator (HU) in realistic leveling networks, for which the heights or the vertical displacements of points are known. The study was conducted using the Monte Carlo simulation, in which one repeatedly generates sets of observations related to the measurement data, then calculates values of the estimators and, finally, assesses it with respect to the real coordinates. To simulate outliers we used popular mixture models with two or more normal distributions. It is shown that for small, strong networks robust methods IDS and HU are more accurate than LS, but for large, weak networks occurring in practice there is no significant difference between the considered methods in the accuracy of the solution. Numéro de notice : A2016-653 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/rgg-2016-0023 En ligne : http://dx.doi.org/10.1515/rgg-2016-0023 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81872
in Reports on geodesy and geoinformatics > vol 101 (June 2016) . - pp 70 - 81[article]Context-dependent detection of non-linearly distributed points for vegetation classification in airborne LiDAR / Denis Horvat in ISPRS Journal of photogrammetry and remote sensing, vol 116 (June 2016)
[article]
Titre : Context-dependent detection of non-linearly distributed points for vegetation classification in airborne LiDAR Type de document : Article/Communication Auteurs : Denis Horvat, Auteur ; Borut Žalik, Auteur ; Domen Mongus, Auteur Année de publication : 2016 Article en page(s) : pp 1 – 14 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] analyse de sensibilité
[Termes IGN] classification dirigée
[Termes IGN] détection automatique
[Termes IGN] distribution spatiale
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] méthode robuste
[Termes IGN] morphologie mathématique
[Termes IGN] prise en compte du contexte
[Termes IGN] végétation
[Termes IGN] zone ruraleRésumé : (auteur) This paper proposes a new method for the detection of vegetation in LiDAR data. As vegetation points are characterised by non-linear distributions, they are efficiently recognised based-on large errors obtained when applying the local fitting of planar surfaces. In addition, three contextual filters are introduced capable of dealing with those exceptions that do not conform with previous interpretations. Namely, they are designed for detecting overgrowing vegetation, small objects attached to the planar surfaces (such as balconies, chimneys, and noise within the buildings) and small objects that do not belong to vegetation (vehicles, statues, fences). During the validation, the proposed method achieved over 97% correctness as well as completeness of vegetation recognition in rural areas while its average accuracy in urban settings was 90.7% in terms of F1F1-scores. The method uses only three input parameters and allows for efficient compensation between completeness and correctness, without significantly affecting the F1F1-score. Sensitivity analysis of the method also confirmed the robustness against a sub-optimal definition of the input parameters. Numéro de notice : A2016-576 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2016.02.011 En ligne : https://doi.org/10.1016/j.isprsjprs.2016.02.011 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81706
in ISPRS Journal of photogrammetry and remote sensing > vol 116 (June 2016) . - pp 1 – 14[article]Flying safe : GNSS Robustness for Unmanned Aircraft Systems / Joshua Stubbs in GPS world, vol 27 n° 4 (April 2016)
[article]
Titre : Flying safe : GNSS Robustness for Unmanned Aircraft Systems Type de document : Article/Communication Auteurs : Joshua Stubbs, Auteur ; Dennis M. Akos, Auteur Année de publication : 2016 Article en page(s) : pp 42 - 47 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] drone
[Termes IGN] interférence
[Termes IGN] méthode robuste
[Termes IGN] positionnement par GNSS
[Termes IGN] radiofréquenceRésumé : (éditeur) In this month’s column, we take a look at how radio-frequency interference (RFI) can impact GNSS equipment on unmanned aircraft systems and how robustly can the equipment navigate those systems. Numéro de notice : A2016-220 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans En ligne : http://gpsworld.com/innovation-flying-safe/ Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80689
in GPS world > vol 27 n° 4 (April 2016) . - pp 42 - 47[article]MIDAS robust trend estimator for accurate GPS station velocities without step detection / Geoffrey Blewitt in Journal of geophysical research : Solid Earth, vol 121 n° 3 (March 2016)
[article]
Titre : MIDAS robust trend estimator for accurate GPS station velocities without step detection Type de document : Article/Communication Auteurs : Geoffrey Blewitt, Auteur ; Corné Kremer, Auteur ; William C. Hammond, Auteur ; Julien Gazeaux , Auteur Année de publication : 2016 Article en page(s) : pp 2054 - 2068 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] Amérique du nord
[Termes IGN] coordonnées GPS
[Termes IGN] estimateur
[Termes IGN] méthode robuste
[Termes IGN] série temporelle
[Termes IGN] station GPS
[Termes IGN] valeur aberrante
[Termes IGN] vitesseRésumé : (auteur) Automatic estimation of velocities from GPS coordinate time series is becoming required to cope with the exponentially increasing flood of available data, but problems detectable to the human eye are often overlooked. This motivates us to find an automatic and accurate estimator of trend that is resistant to common problems such as step discontinuities, outliers, seasonality, skewness, and heteroscedasticity. Developed here, Median Interannual Difference Adjusted for Skewness (MIDAS) is a variant of the Theil‐Sen median trend estimator, for which the ordinary version is the median of slopes vij = (xj–xi)/(tj–ti) computed between all data pairs i > j. For normally distributed data, Theil‐Sen and least squares trend estimates are statistically identical, but unlike least squares, Theil‐Sen is resistant to undetected data problems. To mitigate both seasonality and step discontinuities, MIDAS selects data pairs separated by 1 year. This condition is relaxed for time series with gaps so that all data are used. Slopes from data pairs spanning a step function produce one‐sided outliers that can bias the median. To reduce bias, MIDAS removes outliers and recomputes the median. MIDAS also computes a robust and realistic estimate of trend uncertainty. Statistical tests using GPS data in the rigid North American plate interior show ±0.23 mm/yr root‐mean‐square (RMS) accuracy in horizontal velocity. In blind tests using synthetic data, MIDAS velocities have an RMS accuracy of ±0.33 mm/yr horizontal, ±1.1 mm/yr up, with a 5th percentile range smaller than all 20 automatic estimators tested. Considering its general nature, MIDAS has the potential for broader application in the geosciences. Numéro de notice : A2016--176 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/2015JB012552 Date de publication en ligne : 12/02/2016 En ligne : https://doi.org/10.1002/2015JB012552 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91799
in Journal of geophysical research : Solid Earth > vol 121 n° 3 (March 2016) . - pp 2054 - 2068[article]Documents numériques
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