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Can machine learning improve small area population forecasts? A forecast combination approach / Irina Grossman in Computers, Environment and Urban Systems, vol 95 (July 2022)
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Titre : Can machine learning improve small area population forecasts? A forecast combination approach Type de document : Article/Communication Auteurs : Irina Grossman, Auteur ; Kasun Bandara, Auteur ; Tom Wilson, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 101806 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] analyse en composantes principales
[Termes IGN] apprentissage automatique
[Termes IGN] Australie
[Termes IGN] démographie
[Termes IGN] Extreme Gradient Machine
[Termes IGN] infrastructure
[Termes IGN] lissage de données
[Termes IGN] modèle de simulation
[Termes IGN] modèle empirique
[Termes IGN] Nouvelle-Zélande
[Termes IGN] planification stratégique
[Termes IGN] pondération
[Termes IGN] série temporelleRésumé : (auteur) Generating accurate small area population forecasts is vital for governments and businesses as it provides better grounds for decision making and strategic planning of future demand for services and infrastructure. Small area population forecasting faces numerous challenges, including complex underlying demographic processes, data sparsity, and short time series due to changing geographic boundaries. In this paper, we propose a novel framework for small area forecasting which combines proven demographic forecasting methods, an exponential smoothing based algorithm, and a machine learning based forecasting technique. The proposed forecasting combination contains four base models commonly used in demographic forecasting, a univariate forecasting model specifically suitable for forecasting yearly data, and a globally trained Light Gradient Boosting Model (LGBM) that exploits the similarities between a collection of population time series. In this study, three forecast combination techniques are investigated to weight the forecasts generated by these base models. We empirically evaluate our method, by preparing small area population forecasts for Australia and New Zealand. The proposed framework is able to achieve competitive results in terms of forecasting accuracy. Moreover, we show that the inclusion of the LGBM model always improves the accuracy of combination models on both datasets, relative to combination models which only include the demographic models. In particular, the results indicate that the proposed combination framework decreases the prevalence of relatively poor forecasts, while improving the reliability of small area population forecasts. Numéro de notice : A2022-374 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1016/j.compenvurbsys.2022.101806 Date de publication en ligne : 19/04/2022 En ligne : https://doi.org/10.1016/j.compenvurbsys.2022.101806 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100621
in Computers, Environment and Urban Systems > vol 95 (July 2022) . - n° 101806[article]Regional ionospheric corrections for high accuracy GNSS positioning / Tam Dao in Remote sensing, vol 14 n° 10 (May-2 2022)
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Titre : Regional ionospheric corrections for high accuracy GNSS positioning Type de document : Article/Communication Auteurs : Tam Dao, Auteur ; Ken Harima, Auteur ; Brett Anthony Carter, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 2463 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] Australie
[Termes IGN] Continuously Operating Reference Station network
[Termes IGN] correction ionosphérique
[Termes IGN] modèle ionosphérique
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] retard ionosphèriqueRésumé : (auteur) Centimetre-level accurate ionospheric corrections are required for a high accuracy and rapid convergence of Precise Point Positioning (PPP) GNSS positioning solutions. This research aims to evaluate the accuracy of a local/regional ionospheric delay model using a linear interpolation method across Australia. The accuracy of the ionospheric corrections is assessed as a function of both different latitudinal regions and the number and spatial density of GNSS Continuously Operating Reference Stations (CORSs). Our research shows that, for a local region of 5° latitude ×10° longitude in mid-latitude regions of Australia (~30° to 40°S) with approximately 15 CORS stations, ionospheric corrections with an accuracy of 5 cm can be obtained. In Victoria and New South Wales, where dense CORS networks exist (nominal spacing of ~100 km), the average ionospheric corrections accuracy can reach 2 cm. For sparse networks (nominal spacing of >200 km) at lower latitudes, the average accuracy of the ionospheric corrections is within the range of 8 to 15 cm; significant variations in the ionospheric errors of some specific satellite observations during certain periods were also found. In some regions such as Central Australia, where there are a limited number of CORSs, this model was impossible to use. On average, centimetre-level accurate ionospheric corrections can be achieved if there are sufficiently dense (i.e., nominal spacing of approximately 200 km) GNSS CORS networks in the region of interest. Based on the current availability of GNSS stations across Australia, we propose a set of 15 regions of different ionospheric delay accuracies with extents of 5° latitude ×10° longitude covering continental Australia. Numéro de notice : A2022-400 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.3390/rs14102463 Date de publication en ligne : 20/05/2022 En ligne : https://doi.org/10.3390/rs14102463 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100703
in Remote sensing > vol 14 n° 10 (May-2 2022) . - n° 2463[article]Accuracy issues for spatial update of digital cadastral maps / David Pullar in ISPRS International journal of geo-information, vol 11 n° 4 (April 2022)
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Titre : Accuracy issues for spatial update of digital cadastral maps Type de document : Article/Communication Auteurs : David Pullar, Auteur ; Stephen Donaldson, Auteur Année de publication : 2022 Article en page(s) : n° 221 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cadastre étranger
[Termes IGN] Australie
[Termes IGN] base de données foncières
[Termes IGN] compensation
[Termes IGN] données cadastrales
[Termes IGN] lever cadastral
[Termes IGN] méthode des moindres carrés
[Termes IGN] mise à jour
[Termes IGN] parcelle cadastrale
[Termes IGN] plan parcellaire
[Termes IGN] précision des donnéesRésumé : (auteur) All geospatial data are updated periodically. Cadastral parcel mapping, however, has special update requirements that set it apart from other geospatial data. Mapped boundaries change continuously to fit with new survey plans. Additionally, new parcels have to be fitted and aligned with adjoining parcels to merge them into existing cadastral mapping. This is preferably performed by a spatial adjustment approach to systematically improve its accuracy over time. This paper adapts methods for analysis and adjustment of survey networks to improve the accuracy of cadastral mapping with better coordinate positioning and survey plan dimensions. Case studies for both hypothetical and real cadastral mapping are used to illustrate the issues and spatially resolve errors. Adjustment results achieve an accuracy consistent with other GIS layers and boundary features visible in high-resolution orthoimagery. Graphical charts based on stress–strain relationships provide a simplified means to interpret post-adjustment results to identify and fix potential errors. Numéro de notice : A2022-285 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.3390/ijgi11040221 Date de publication en ligne : 24/03/2022 En ligne : https://doi.org/10.3390/ijgi11040221 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100305
in ISPRS International journal of geo-information > vol 11 n° 4 (April 2022) . - n° 221[article]Problems with models assessing influences of tree size and inter-tree competitive processes on individual tree growth: a cautionary tale / P.W. West in Journal of Forestry Research, vol 33 n° 2 (April 2022)
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Titre : Problems with models assessing influences of tree size and inter-tree competitive processes on individual tree growth: a cautionary tale Type de document : Article/Communication Auteurs : P.W. West, Auteur ; D.A. Ratkowsky, Auteur Année de publication : 2022 Article en page(s) : pp 565 - 577 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] arbre (flore)
[Termes IGN] Australie
[Termes IGN] croissance végétale
[Termes IGN] Eucalyptus pilularis
[Termes IGN] forêt équienne
[Termes IGN] hauteur des arbres
[Termes IGN] modèle de croissance végétale
[Termes IGN] régression non linéaire
[Termes IGN] surface terrière
[Vedettes matières IGN] ForesterieRésumé : (auteur) In forest growing at any one site, the growth rate of an individual tree is determined principally by its size, which reflects its metabolic capacity, and by competition from neighboring trees. Competitive effects of a tree may be proportional to its size; such competition is termed ‘symmetric’ and generally involves competition below ground for nutrients and water from the soil. Competition may also be ‘asymmetric’, where its effects are disproportionate to the size of the tree; this generally involves competition above ground for sunlight, when larger trees shade smaller, but the reverse cannot occur. This work examines three model systems often seen as exemplars relating individual tree growth rates to tree size and both competitive processes. Data of tree stem basal area growth rates in plots of even-aged, monoculture forest of blackbutt (Eucalyptus pilularis Smith) growing in sub-tropical eastern Australia were used to test these systems. It was found that none could distinguish between size and competitive effects at any time in any one stand and, thus, allow quantification of the contribution of each to explaining tree growth rates. They were prevented from doing so both by collinearity between the terms used to describe each of the effects and technical problems involved in the use of nonlinear least-squares regression to fit the models to any one data set. It is concluded that quite new approaches need to be devised if the effects on tree growth of tree size and competitive processes are to be quantified and modelled successfully. Numéro de notice : A2022-335 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article Date de publication en ligne : 04/10/2021 En ligne : https://doi.org/10.1007/s11676-021-01395-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100673
in Journal of Forestry Research > vol 33 n° 2 (April 2022) . - pp 565 - 577[article]The re-invention of the Goori cultural landscape: Telling the country: Mapping two pockets / Paul Memmott in Cartographica, Vol 57 n° 1 (Spring)
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Titre : The re-invention of the Goori cultural landscape: Telling the country: Mapping two pockets Type de document : Article/Communication Auteurs : Paul Memmott, Auteur ; Ray Kerkhove, Auteur ; Alex Bond, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 65-79 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Brisbane (Australie)
[Termes IGN] communication cartographique
[Termes IGN] culture
[Termes IGN] données textuelles
[Termes IGN] droit foncier
[Termes IGN] ethnologie
[Termes IGN] ontologie
[Termes IGN] patrimoine culturel
[Termes IGN] période coloniale
[Termes IGN] Queensland (Australie)
[Vedettes matières IGN] CartologieRésumé : (auteur) This article analyzes the authors’ map of the Aboriginal geography of St Lucia and Long Pocket, two riverine suburbs of Brisbane, upstream of the central business district, and containing two of the University of Queensland’s campuses. The map is a prism into the wider “Goori” Aboriginal society of the early 1800s. The map was generated by two Aboriginal scholars and an anthropologist using a practice-based ontological approach and by historians using early textual sources. The map juxtaposes a geopolitical edge against contemporary metropolitan mapping, providing a foundation of First Nations geography to underlie and undermine the power of colonial and postcolonial cartography. Numéro de notice : A2022-246 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.3138/cart-2021-0022 Date de publication en ligne : 15/03/2022 En ligne : https://doi.org/10.3138/cart-2021-0022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100189
in Cartographica > Vol 57 n° 1 (Spring) . - pp 65-79[article]Réservation
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