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Measuring differential access to facilities between population groups using spatial Lorenz curves and related indices / Gordon A. Cromley in Transactions in GIS, Vol 23 n° 6 (November 2019)  

Public [article]  inTransactions in GIS > Vol 23 n° 6 (November 2019) . - pp 1332 - 1351 Titre : Measuring differential access to facilities between population groups using spatial Lorenz curves and related indices Type de document : Article/Communication Auteurs : Gordon A. Cromley, Auteur Année de publication : 2019 Article en page(s) : pp 1332 - 1351 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] accessibilité [Termes IGN] coefficient de Gini [Termes IGN] commerce [Termes IGN] courbe de Lorenz [Termes IGN] distribution spatiale [Termes IGN] équipement collectif [Termes IGN] inégalité [Termes IGN] Ohio (Etats-Unis) [Termes IGN] population [Termes IGN] segmentation [Termes IGN] service public [Termes IGN] sociologie [Termes IGN] système d'information géographique Résumé : (auteur) Access to certain types of facilities can promote health and well‐being. When population and facilities are not uniformly distributed across the landscape, inequities in accessibility may occur. Current research into GIS‐based accessibility measures has focused primarily on spatial inequities between different geographic locations but not directly on differences in accessibility between subgroups of the population. The research presented here develops a new method for measuring differential accessibility to facilities between various segments of the population. The method extends concepts and techniques in spatial point pattern analysis that account for the spatial structure of demand and its relationship to supply. In this approach, the traditional Lorenz curve and its associated indices, the Gini coefficient and the dissimilarity index, which are used to measure inequality, are recast in spatial terms for measuring differences in accessibility between population subgroups. An analysis of spatial accessibility to grocery stores in Akron, OH illustrates the value of the spatial Lorenz curve and its associated indices compared to other methods. Numéro de notice : A2019-567 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12577 Date de publication en ligne : 06/10/2019 En ligne : https://onlinelibrary.wiley.com/doi/10.1111/tgis.12577 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94419 [article]

Introduction to Statistics and Data Analysis / Christian Heumann (2016)  

Public Titre : Introduction to Statistics and Data Analysis : With Exercises, Solutions and Applications in R Type de document : Guide/Manuel Auteurs : Christian Heumann, Auteur ; Michael Schomaker, Auteur Editeur : Springer International Publishing Année de publication : 2016 Importance : 456 p. Format : 16 x 24 cm ISBN/ISSN/EAN : 978-3-319-46162-5 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Statistiques [Termes IGN] coefficient de Gini [Termes IGN] courbe de Lorenz [Termes IGN] estimateur [Termes IGN] probabilités [Termes IGN] R (langage) [Termes IGN] régression linéaire [Termes IGN] variable aléatoire Résumé : (éditeur) This introductory statistics textbook conveys the essential concepts and tools needed to develop and nurture statistical thinking. It presents descriptive, inductive and explorative statistical methods and guides the reader through the process of quantitative data analysis. In the experimental sciences and interdisciplinary research, data analysis has become an integral part of any scientific study. Issues such as judging the credibility of data, analyzing the data, evaluating the reliability of the obtained results and finally drawing the correct and appropriate conclusions from the results are vital. The text is primarily intended for undergraduate students in disciplines like business administration, the social sciences, medicine, politics, macroeconomics, etc. It features a wealth of examples, exercises and solutions with computer code in the statistical programming language R as well as supplementary material that will enable the reader to quickly adapt all methods to their own applications. Note de contenu : 1- Descriptive Statistics 2- Probability Calculus 3- Inductive Statistics Numéro de notice : 25822 Affiliation des auteurs : non IGN Thématique : INFORMATIQUE/MATHEMATIQUE Nature : Manuel En ligne : https://doi.org/10.1007/978-3-319-46162-5 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95097

A concentration-based approach to data classification for choropleth mapping / Robert G. Cromley in International journal of geographical information science IJGIS, vol 29 n° 10 (October 2015)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 29 n° 10 (October 2015) . - pp 1845 - 1863 Titre : A concentration-based approach to data classification for choropleth mapping Type de document : Article/Communication Auteurs : Robert G. Cromley, Auteur ; Shuowei Zhang, Auteur ; Natalia Vorotyntseva, Auteur Année de publication : 2015 Article en page(s) : pp 1845 - 1863 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie numérique [Termes IGN] carte choroplèthe [Termes IGN] classification [Termes IGN] courbe de Lorenz [Termes IGN] données statistiques [Termes IGN] précision des données Résumé : (Auteur) The choropleth map is a device used for the display of socioeconomic data associated with an areal partition of geographic space. Cartographers emphasize the need to standardize any raw count data by an area-based total before displaying the data in a choropleth map. The standardization process converts the raw data from an absolute measure into a relative measure. However, there is recognition that the standardizing process does not enable the map reader to distinguish between low–low and high–high numerator/denominator differences. This research uses concentration-based classification schemes using Lorenz curves to address some of these issues. A test data set of nonwhite birth rate by county in North Carolina is used to demonstrate how this approach differs from traditional mean–variance-based systems such as the Jenks’ optimal classification scheme. Numéro de notice : A2015-612 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2015.1058388 En ligne : https://doi.org/10.1080/13658816.2015.1058388 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78042 [article]

Forest structure indicators based on tree size inequality and their relationships to airborne laser scanning / Rubén Valbuena (2015)  

Public Titre : Forest structure indicators based on tree size inequality and their relationships to airborne laser scanning Type de document : Thèse/HDR Auteurs : Rubén Valbuena, Auteur Editeur : Vantaa [Finlande] : Finnish Society of Forest Science Année de publication : 2015 Collection : Dissertationes forestales, ISSN 1795-7389 num. 205 Format : 21 x 30 cm ISBN/ISSN/EAN : 978-951-651-499-7 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] composition d'un peuplement forestier [Termes IGN] courbe de Lorenz [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] entropie [Termes IGN] hauteur des arbres Résumé : (auteur) The subject of this doctoral thesis is the non-spatial indices of horizontal differentiation that can be used as indicators of forest structural complexity, specifically as descriptors of tree size inequality. The body of the thesis focuses primarily on the indicators themselves, while the appended articles tackle issues mainly related to their practical estimation using airborne laser scanning (ALS) remote sensing. The overall research is framed in the context of developing a system of indicators that can be applied at pan-European level, whose implementation in practice is foreseen in the advent of national ALS surveying programmes. A list of indicators available in the scientific literature for describing forest structural heterogeneity by means of horizontal differentiation was tested. Indices based on the theory of information demonstrated critical inconsistencies, which rendered them inadequate for describing tree size inequality. This was revealed using the theory on intrinsic ordering, and illustrated with diversity and equitability profiles. The use of Shannon, and similar indices based on generalized entropy, to describe diversity between size classes, which has been common practice, is therefore discouraged. The link between majorization and Lorenz ordering was established for the specific case of tree size distributions, discussing the reliability of analysing the Lorenz curve to fully describe size inequality in tree populations. In forest science, the Lorenz curve relates stem frequency distributions to their corresponding basal area-weighted distributions. Indicators based on the Lorenz curve, such as the Gini coefficient (GC), were therefore chosen for their ALS-based estimation. Adding an indicator describing Lorenz curve’s asymmetry was deemed necessary for describing relative understorey development. Research demonstrated the convenience of using the basal area larger than the mean (BALM), as it defined the position of the Lorenz curve inflexion point, which depicts the quadratic mean diameter (QMD). It was observed that, when using Lorenz curves to describe forest structure, the position of the QMD should be compared with the Lorenz curve of a theoretical uniform DBH distribution, which represents maximum entropy. Accordingly, this thesis includes a discussion of how Lorenz ordering can be used as a method, providing a scale for simultaneously comparing relative dispersion and entropy. In conclusion, the final recommended indicators are GC and BALM, since this bivariate description of forest structure fully characterises the relationships of relative dominance among trees in a forest population. The most similar neighbour (MSN) imputation of tree lists is defended as a substantially convenient method for predicting these indicators by ALS. Numéro de notice : 14976 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Thèse étrangère Note de thèse : PhD : Forest Sciences : University of Eastern Finland : 2015 En ligne : http://www.metla.fi/dissertationes/df205.htm Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78363

Comparison of airborne laser scanning methods for estimating forest structure indicators based on Lorenz curves / Rubén Valbuena in ISPRS Journal of photogrammetry and remote sensing, vol 95 (September 2014)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 95 (September 2014) . - pp 23 – 33 Titre : Comparison of airborne laser scanning methods for estimating forest structure indicators based on Lorenz curves Type de document : Article/Communication Auteurs : Rubén Valbuena, Auteur ; Jari Vauhkonen, Auteur ; Petteri Packalen, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 23 – 33 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] analyse comparative [Termes IGN] arbre (flore) [Termes IGN] courbe de Lorenz [Termes IGN] détection d'objet [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] forêt [Termes IGN] indicateur [Termes IGN] structure d'un peuplement forestier Résumé : (Auteur) The purpose of this study was to compare a number of state-of-the-art methods in airborne laser scanning (ALS) remote sensing with regards to their capacity to describe tree size inequality and other indicators related to forest structure. The indicators chosen were based on the analysis of the Lorenz curve: Gini coefficient (GC), Lorenz asymmetry (LA), the proportions of basal area (BALM) and stem density (NSLM) stocked above the mean quadratic diameter. Each method belonged to one of these estimation strategies: (A) estimating indicators directly; (B) estimating the whole Lorenz curve; or (C) estimating a complete tree list. Across these strategies, the most popular statistical methods for area-based approach (ABA) were used: regression, random forest (RF), and nearest neighbour imputation. The latter included distance metrics based on either RF (NN–RF) or most similar neighbour (MSN). In the case of tree list estimation, methods based on individual tree detection (ITD) and semi-ITD, both combined with MSN imputation, were also studied. The most accurate method was direct estimation by best subset regression, which obtained the lowest cross-validated coefficients of variation of their root mean squared error CV(RMSE) for most indicators: GC (16.80%), LA (8.76%), BALM (8.80%) and NSLM (14.60%). Similar figures [CV(RMSE) 16.09%, 10.49%, 10.93% and 14.07%, respectively] were obtained by MSN imputation of tree lists by ABA, a method that also showed a number of additional advantages, such as better distributing the residual variance along the predictive range. In light of our results, ITD approaches may be clearly inferior to ABA with regards to describing the structural properties related to tree size inequality in forested areas. Numéro de notice : A2014-473 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2014.06.002 En ligne : https://doi.org/10.1016/j.isprsjprs.2014.06.002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74050 [article]

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