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Characteristics of seasonal variations and noises of the daily double-difference and PPP solutions / Kamil Maciuk in Journal of applied geodesy, vol 15 n° 1 (January 2021)
Titre : Characteristics of seasonal variations and noises of the daily double-difference and PPP solutions Type de document : Article/Communication Auteurs : Kamil Maciuk, Auteur ; Inese Vārna, Auteur ; Chang Xu, Auteur Année de publication : 2021 Article en page(s) : pp 61 - 73 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] bruit blanc
[Termes descripteurs IGN] bruit rose
[Termes descripteurs IGN] déformation de la croute terrestre
[Termes descripteurs IGN] double différence
[Termes descripteurs IGN] Lettonie
[Termes descripteurs IGN] positionnement ponctuel précis
[Termes descripteurs IGN] série temporelle
[Termes descripteurs IGN] station de référence
[Termes descripteurs IGN] variance de Hadamard
[Termes descripteurs IGN] variation saisonnière
[Termes descripteurs IGN] vitesse
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) Long term GNSS observations provided by networks of the continuously operating reference stations (CORS) allow for determination of the global and local tectonic plate movements and seasonal variations. In recent years, PPP (Precise Point Positioning) technique has become increasingly popular and most likely in the future will replace relative positioning with CORS stations. In this paper, we discuss the difference of the velocity and seasonal component estimates of 25 Latvian CORS stations on the basis of daily PPP solutions from the Nevada Geodetic Laboratory and double-difference solutions from the Institute of Geodesy and Geoinformatics of the University of Latvia. Time series of each coordinate component for 9-year time period were determined by the usage of the Tsview software and seasonal existence of linear, annual, semi-annual factors and their uncertainties were determined. Breaks (e. g., antenna and receiver changes) were also taken into account. We then assessed the noise characteristics of these time series with the use of overlapping Hadamard variance (OHVAR). The result shows that OHVAR is computationally cheap, and the dominating power-law noise, including flicker and random walk. However Hadamard deviation of the PPP and double-difference solutions scatters differently for a whole year averaging time due to the different GNSS data strategies. Numéro de notice : A2021-045 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2020-0042 date de publication en ligne : 08/12/2020 En ligne : https://doi.org/10.1515/jag-2020-0042 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96772
in Journal of applied geodesy > vol 15 n° 1 (January 2021) . - pp 61 - 73[article]
Titre : Norway Spruce Seedlings from an Eastern Baltic Provenance Show Tolerance to Simulated Drought Type de document : Article/Communication Auteurs : Roberts Matisons, Auteur ; Oskars Krišāns, Auteur ; Aris Jansons, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : n° 82 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] adaptation (biologie)
[Termes descripteurs IGN] analyse de sensibilité
[Termes descripteurs IGN] chlorophylle
[Termes descripteurs IGN] état du sol
[Termes descripteurs IGN] irrigation
[Termes descripteurs IGN] Lettonie
[Termes descripteurs IGN] photosynthèse
[Termes descripteurs IGN] Picea abies
[Termes descripteurs IGN] sécheresse
[Termes descripteurs IGN] stress hydrique
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) In Northern Europe, an increase in heterogeneity of summer precipitation regime will subject forests to water deficit and drought. This is particularly topical for Norway spruce (Picea abies Karst.), which is a drought sensitive, yet economically important species. Nevertheless, local populations still might be highly plastic and tolerant, supporting their commercial application. Accordingly, the tolerance of Norway spruce seedlings from an Eastern Baltic provenance (western part of Latvia) to artificial drought according to soil type was assessed in a shelter experiment. To simulate drought, seedlings were subjected to reduced amounts (0%, 25%, 50%, 75%, and 100%) of naturally occurring precipitation (irrigation intensity). Three soil types (oligotrophic mineral, mesotrophic mineral, and peat) were tested. Seedling height, chlorophyll a concentration, and fluorescence parameters were measured. Both growth and photochemical reactions were affected by the irrigation intensity, the effect of which experienced an interacted with soil type, implying complex controls of drought sensitivity. Seedlings were more sensitive to irrigation intensity on mesotrophic mineral soil, as suggested by growth and photosynthetic activity. However, the responses were nonlinear, as the highest performance (growth and fluorescence parameters) of seedlings occurred in response to intermediate drought. On peat soil, which had the highest water-bearing capacity, an inverse response to irrigation intensity was observed. In general, fluorescence parameters were more sensitive and showed more immediate reaction to soil water deficit than concentration of chlorophyll on mesotrophic mineral and peat soils, while the latter was a better indicator of seedling performance on oligotrophic soil. This indicated considerable plastic acclimation and hence tolerance of seedlings from the local Norway spruce population to drought, though drought sensitivity is age-dependent. Numéro de notice : A2021-145 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.3390/f12010082 date de publication en ligne : 14/01/2021 En ligne : https://doi.org/10.3390/f12010082 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97048
in Forests > vol 12 n° 1 (January 2021) . - n° 82[article]
Titre : Reintroduction of the European bison (Bison bonasus) in central-eastern Europe: a case study Type de document : Article/Communication Auteurs : Cathlin M. Lord, Auteur ; Kylie P. Wirebach, Auteur ; Jennifer Tompkins, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 1628 - 1647 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique
[Termes descripteurs IGN] analyse multicritère
[Termes descripteurs IGN] analyse spatiale
[Termes descripteurs IGN] biodiversité
[Termes descripteurs IGN] combinaison linéaire ponderée
[Termes descripteurs IGN] écosystème
[Termes descripteurs IGN] Europe centrale
[Termes descripteurs IGN] faune
[Termes descripteurs IGN] habitat animal
[Termes descripteurs IGN] Lettonie
[Termes descripteurs IGN] politique de conservation (biodiversité)
[Termes descripteurs IGN] Pologne
[Termes descripteurs IGN] population animale
[Termes descripteurs IGN] processus d'analyse hiérarchiqueRésumé : (auteur) European bison (Bison bonasus), a flagship species for the burgeoning re-wildling movement, faced challenges common to large mammals globally. These include deforestation, land use conversion, poaching, and a lack of genetic diversity. Despite these limitations, organizations such as Rewilding Europe seek to reintroduce the species to its historic range. This study focused on finding suitable reintroduction locations for a population of at least 120 individuals. Through GIS-based multi-criteria decision-making using weighted linear combination and analytical hierarchy process, a model based on known bison habitat preferences, human-centered habitat constraints, and surface geography was used to identify regions large enough to accommodate a new herd. The study area included central-eastern Europe Union countries, specifically Germany, Poland, Lithuania, and Latvia. The model identified several highly suitable regions large enough to support a new herd, with the most optimal located in Poland. Highly suitable areas represented 2.7% of the study region. Relative isolation of suitable regions reinforced the challenges of promoting gene flow between reintroduced European bison herds. This model can be replicated in other conservation planning contexts, including reintroduction of large herbivores considering anthropogenic, ecological, and physical conditions. Numéro de notice : A2020-408 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2019.1672876 date de publication en ligne : 10/10/2019 En ligne : https://doi.org/10.1080/13658816.2019.1672876 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95467
in International journal of geographical information science IJGIS > vol 34 n° 8 (August 2020) . - pp 1628 - 1647[article]
Titre : Tree cover mapping using hybrid fuzzy C-means method and multispectral satellite images Type de document : Article/Communication Auteurs : Linda Gulbe, Auteur ; Aleksandrs Kozlovs, Auteur ; Janis Donis, Auteur ; Agris Tradkovs, Auteur Année de publication : 2019 Article en page(s) : pp 113 - 123 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes descripteurs IGN] carte de la végétation
[Termes descripteurs IGN] classification barycentrique
[Termes descripteurs IGN] classification floue
[Termes descripteurs IGN] estimation statistique
[Termes descripteurs IGN] image Landsat-8
[Termes descripteurs IGN] image Landsat-ETM+
[Termes descripteurs IGN] image Landsat-OLI
[Termes descripteurs IGN] image Landsat-TM
[Termes descripteurs IGN] image multibande
[Termes descripteurs IGN] image Sentinel-MSI
[Termes descripteurs IGN] inventaire forestier (techniques et méthodes)
[Termes descripteurs IGN] inventaire forestier étranger (données)
[Termes descripteurs IGN] LettonieRésumé : (auteur) Countrywide up-to-date tree cover maps provide valuable information for planning and management purposes to investigate location of the resources and to identify afforestation and deforestation patterns. Landsat programme offers freely available satellite data with time span more than three decades and it can serve as bases for tree cover map calculation using satellite image classification; however, practical use of classification methods is limited due to lack of user-friendly solutions and complex interpretation of the results. The objective of this study is to evaluate user-friendly hybrid classification scheme for tree cover mapping in Latvia and to explore the nature of the spectral classes and consistency of the results when methodology is applied to images of different dates. Tree cover in this context means the area covered by crown of the tree, which may or may not be considered as forest according to local provisions. Tree cover is estimated using unsupervised fuzzy c-means methods with the stability check to ensure the presence of the same spectral classes in independent tests. Spectral classes are classified into two categories: tree cover and other by employing k-nearest neighbours. Such approach does not require high quality sample data and does not include user defined internal parameters of the algorithms (however, they can be specified if needed). The best overall accuracy achieved for year 2014 was 94.2% with producer's accuracy 98.7% (tree cover), 90.5% (other land cover), user's accuracy 90.0% (tree cover), 98.8% (other land cover) and kappa 0.89. Consistency studies showed high impact (within 10% of overall accuracy) of unique conditions during the image acquisition. Some of the spectral classes represent borderline case between relatively dense tree cover and other land cover types like sparse young stands. Those cases are the main threat to the consistency between the results of different dates and seasons. Numéro de notice : A2019-375 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : sans En ligne : https://www.balticforestry.mi.lt/bf/PDF_Articles/2019-25%5B1%5D/Baltic%20Forestr [...] Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93417
in Baltic forestry > vol 25 n° 1 (2019) . - pp 113 - 123[article]
Titre : Validation of medium-scale historical maps of southern Latvia for evaluation of impact of continuous forest cover on the present-day mean stand area and tree species richness Type de document : Article/Communication Auteurs : Anda Fescenko, Auteur ; Martins Lukins, Auteur ; Ilja Fescenko, Auteur Année de publication : 2016 Article en page(s) : pp 51 - 62 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes descripteurs IGN] analyse multivariée
[Termes descripteurs IGN] carte ancienne
[Termes descripteurs IGN] continuité géographique
[Termes descripteurs IGN] couvert forestier
[Termes descripteurs IGN] données multitemporelles
[Termes descripteurs IGN] écosystème forestier
[Termes descripteurs IGN] feuillu
[Termes descripteurs IGN] inventaire forestier étranger (données)
[Termes descripteurs IGN] Lettonie
[Termes descripteurs IGN] régression
[Termes descripteurs IGN] richesse floristique
[Termes descripteurs IGN] station forestière
[Termes descripteurs IGN] utilisation du solRésumé : (auteur) Medium-scale historical maps are often the only cartographic source of former forest area distribution on a regional level. In conjunction with a database of the current distribution of species or functional traits, maps may be valuable tool for studying the impact of previous land use on ecosystems. In this study a heterogeneous set of historical maps was used to reconstruct the multi-temporal pattern of the forest area in a moderately forested region (5,180 km2) of southern Latvia during the last 220 years. Changes in the total forest cover were assessed in four time slices and compared with available historical statistical data. To validate the obtained multi-temporal data for ecological studies, the impact of continuous forest cover on the present-day mean stand area and tree species richness derived from the present-day forest inventory database of 94,886 stands was quantified by bivariate and regression analyses. We found no significant impact of inaccuracy of the historical maps on the entire forest continuity pattern of the study area. In particular, the diversity metrics dependencies on the forest continuity can be described by quadratic regression models with coefficients of determination close to one. We also found that the mean stand area is for about 18% larger in woodlands with longer forest continuity irrespective of the forest type. The older woodland the less difference was found between boreal deciduous and nemoral deciduous forests in terms of tree species richness. Numéro de notice : A2016--096 Affiliation des auteurs : non IGN Thématique : FORET/GEOMATIQUE Nature : Article En ligne : https://www.balticforestry.mi.lt/bf/PDF_Articles/2016-22%5b1%5d/e-Baltic%20Fores [...] Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84649
in Baltic forestry > vol 22 n° 1 [01/02/2016] . - pp 51 - 62[article]PermalinkPermalinkPermalinkPermalinkDie Bestimmung des Richtungsvektors Riga-Sofia aus Beobachtungen des Satelliten "Echo 2" / K. Arnold (1971)
PermalinkRapport de la commission permanente de phototopographie aérienne préparé pour le congrès international de géographie, Varsovie, 1934 / Commission permanente de phototopographie (1934)
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