Wyniki wyszukiwania - Biblioteka Nauki

1

Administrative data as a source of information about employed persons

100%

Gieranczyk W. , Ziolkowski D.

Wiadomości Statystyczne

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2022

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tom 67

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nr 01

2

Indicators of landscape diversity derived from remote sensing based land cover maps - spatial and thematic aspects

80%

Ziolkowski D. , Turlej K. , Bochenek Z.

Ecological Questions

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2013

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tom 17

EN

Landscape is heterogeneous part of the Earth surface, forming mosaic of various habitats organized at different scales and levels (Johnson et al. 1992). The landscape pattern has important impact on ecological processes; hence its analysis through quantitative measures is essential for environmental studies. There are many indicators characterizing spatial structure of landscape at different level of detail; they enable analysis of landscape fragmentation at patch level, through studies at habitat level up to complex analyses at landscape level. Seven indicators, which are related to various levels of detail, were selected at the presented work. The following indicators have been studied: Patch Density, Edge Density, Patch Richness, Simpson Diversity Index, Natural Patch Richness, Percentage of Natural Landscape, Mean Natural Patch Area (McGarigal & Marks 1995). First two indicators were used for analysis of landscape fragmentation at patch level, next two at land cover level, while the last three were applied for studies of natural and semi-natural classes at both levels. The studies were performed at six test areas located in different regions of Europe (France, Germany, Poland, Latvia, Spain and Italy), using two different land cover maps. First map was based on Very High Resolution (VHR) Kompsat satellite images (4 m spatial resolution); it included 8 land cover categories with 0.25 ha Minimum Mapping Unit (MMU). CORINE Land Cover (CLC) map 2006 (25 ha MMU) was the second map used for analyses. Number of land cover classes in case of CLC map varied from 9 for Poland till 14 for France. All above mentioned indicators were calculated for grids with 100, 200, 500 and 1000 meter cell size, corresponding to 1, 4, 25 and 100 ha, respectively. The obtained results reveal high usefulness of land cover maps based on VHR satellite images for analysis of landscape fragmentation, even for grids with 100 m cell size. It was found that at patch level these materials are superior to CLC classifications, irrespective of cell area. In case of land cover level VHR data are better while using 100 and 200 m grid cells, whereas for larger cell sizes – 500 and 1000 m – results are not so evident, depending on degree of landscape fragmentation and spatial structure characteristic for individual land cover classes.

3

Dual-Polarimetric signatures of vegetation – a case study Biebrza

80%

Ziolkowski D. , Malek I. , Budzynska M.

Geoinformation Issues

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2013

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tom Vol. 5, no. 1(5)

29--41

EN

The main objective of the research presented in this article is to analyse the polarimetric characteristics of three main types of natural vegetation occurring in the Biebrza National Park – forests, shrubs and non-forest land communities covering wetlands. The variability of many different polarimetric products of signal decomposition, depending on the type of vegetation, the microwave image acquisition period and the method of their preliminary treatment, was analysed. An attempt was also made to assess how much polarimetric methods can be useful for modelling biophysical parameters of vegetation. The study used six dualpolarized (HH and HV) ALOS satellite images recorded during the growing season in the years 2008, 2009 and 2010. The images were processed in parallel, using different parameters, in order to estimate the impact of the spatial resolution of images and methods of speckle noise filtering on the value of polarimetric characteristics of different types of vegetation. All methods of polarimetric signal decompositions available using ESA POLSARPRO 4.2 software were tested. Three of them, i.e. the Alpha parameter from the H/A/Alpha decomposition (Cloud and Pottier, 1996) containing information about the dominant scattering mechanisms and two types of entropy: the entropy from the H/A/Alpha decomposition and the Shannon Entropy were selected for further analysis. The analysed years differed quite significantly from one another in the agro-meteorological conditions of plant growth. It was a cause of significant differences between the values of polarimetric characteristics in images recorded at the same season but in different years. During the growing season individual products of polarimetric signal decomposition are characterized by different variability. This demonstrates the dependence of different polarimetric characteristics on various biophysical parameters of the environment. It was observed that they are characterized by greater information content than the backscattering coefficient, especially if they are subjected to the process of increasing the resolution (oversampling). They can be used to model the biophysical parameters of vegetation.

PL

Głównym celem badań prezentowanych w tym artykule jest analiza charakterystyk polarymetrycznych trzech głównych typów roślinności naturalnej występującej na terenie Biebrzańskiego Parku Narodowego – lasów, zakrzaczeń oraz porastających tereny podmokłe lądowych zbiorowisk nieleśnych. Przeanalizowano zmienność wartości wielu różnych produktów polarymetrycznych dekompozycji sygnału w zależności od rodzaju roślinności, terminu rejestracji obrazów mikrofalowych oraz sposobu ich wstępnego przetworzenia. Została podjęta również próba oceny, na ile metody polarymetryczne mogą być przydatne do celów modelowania parametrów biofizycznych roślinności. W badaniach wykorzystano sześć dwupolaryzacyjnych (HH i HV) obrazów z satelity ALOS zarejestrowanych w trakcie trwania sezonu wegetacyjnego w latach 2008, 2009 i 2010. Obrazy poddano wstępnemu przetworzeniu, wykorzystując do tego różne algorytmy i parametry, w celu oszacowania wpływu rozdzielczości przestrzennej oraz redukcji plamkowania na wartości sygnatur polarymetrycznych roślinności. Wykorzystano wszystkie algorytmy polarymetrycznych dekompozycji sygnału dostępnych w programie ESA POLSARPRO 4.2. Trzy z nich: Alpha i Entropia z dekompozycji H/A/Ralpha (Cloud and Pottier, 1996) oraz Entropia Shannona zostały wybrane do dalszych analiz. Poszczególne lata, w których rejestrowane były obrazy radarowe, różniły się dość istotnie między sobą agrometeorologicznymi warunkami wzrostu roślin. Było to przyczyną znaczących różnic w wartościach charakterystyk polarymetrycznych na obrazach zarejestrowanych w tym samym terminie, ale w różnych latach. W trakcie trwania sezonu wegetacyjnego poszczególne produkty polarymetrycznej dekompozycji sygnału cechuje różna zmienność. Świadczy to o zależności poszczególnych charakterystyk polarymetrycznych od różnych parametrów biofizycznych środowiska. Zaobserwowano, że charakteryzują się one większą zawartością informacyjną, niż współczynnik wstecznego rozproszenia, zwłaszcza jeżeli zostaną poddane procesowi zwiększenia rozdzielczości (oversampling). Mogą zostać wykorzystane do modelowania biofizycznych parametrów roślinności.

4

Estimation of height changes of GNSS stations from the solutions of short vectors and PSI measurements

70%

Krynski J. , Zak L. , Ziolkowski D. , Cisak J. , Lagiewska M.

Geodesy and Cartography

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2017

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tom Vol. 66, no. 1

73--88

EN

Time series of weekly and daily solutions for coordinates of permanent GNSS stations may indicate local deformations in Earth’s crust or local seasonal changes in the atmosphere and hydrosphere. The errors of the determined changes are relatively large, frequently at the level of the signal. Satellite radar interferometry and especially Persistent Scatterer Interferometry (PSI) is a method of a very high accuracy. Its weakness is a relative nature of measurements as well as accumulation of errors which may occur in the case of PSI processing of large areas. It is thus beneficial to confront the results of PSI measurements with those from other techniques, such as GNSS and precise levelling. PSI and GNSS results were jointly processed recreating the history of surface deformation of the area of Warsaw metropolitan with the use of radar images from Envisat and Cosmo-SkyMed satellites. GNSS data from Borowa Gora and Jozefoslaw observatories as well as from WAT1 and CBKA permanent GNSS stations were used to validate the obtained results. Observations from 2000–2015 were processed with the Bernese v.5.0 software. Relative height changes between the GNSS stations were determined from GNSS data and relative height changes between the persistent scatterers located on the objects with GNSS stations were determined from the interferometric results. The consistency of results of the two methods was 3 to 4 times better than the theoretical accuracy of each. The joint use of both methods allows to extract a very small height change below the level of measurement error.