National Repository of Grey Literature 22 records found  previous11 - 20next  jump to record: Search took 0.01 seconds. 
Identification of potentially suitable habitats for occurrence of European Ground Squirrel (Spermophilus citellus) using remote sensing
Kadeřábková, Tereza ; Kupková, Lucie (advisor) ; Hais, Martin (referee)
The aim of the thesis was to evaluate the possibilities of remote sensing (RS) data with different spatial resolution (UAV data with 5cm resolution, RapidEye satellite data with 5m resolution and Sentinel-2A data with 10m resolution) and of remote sensing methods (unsupervised and supervised classifications, vegetation indices NDVI and TVI) to identify potentially suitable habitats for European ground squirrel. The analyses were first carried out in Velké Pavlovice small area of interest and consequently in a broader area of interest comprised of five regions of Moravia and Slovakia. Data form mapping of biotopes and squirrels' burrows collected within a project "Sysli pro krajinu, krajina pro sysly" (European ground squirrels for landscape, landscape for European ground squirrels) were also used for the analyses. Remote sensing methods were first tested in Velké Pavlovice area using RapidEye data. The method providing the best results in the detection of European ground squirrel burrows was then used for a burrows detection in the broader area of interest (five regions) using Sentinel-2A data. The accuracy of results was defined as a proportion of the burrows detected by the resulting layer derived from RS data to the overall number of burrows mapped in the field. Best results were obtained for...
Regional yield forecasting for improved decision making in the plant production
Trnka, Miroslav ; Hlavinka, Petr ; Kudláčková, Lucie ; Balek, Jan ; Meitner, Jan ; Možný, Martin ; Štěpánek, Petr ; Bartošová, Lenka ; Semerádová, Daniela ; Bláhová, Monika ; Lukas, Vojtěch ; Žalud, Zdeněk
The methodology describes how to predict yields of key crops, and at the same time addresses reliability of the predictions and how these can be used. The ability to predict yield levels more than 2 months prior the harvest on the level of regions (NUTS3¨) and districts (LAU1) brings also new opportunities to mitigate impacts of adverse conditions. The methodology shows that the yield forecasts and yield anomalies in particular are consistent and usable in practices. In this methodology, the results of 2018 yield forecasts are presented as an example. The yield forecasting system for the Czech Republic is fully functional and is and will be available through www.vynosy-plodin.cz.
Predicting light use efficiency using optical vegetation indices at various time scales and environmental conditions
Kováč, Daniel ; Ač, Alexander ; Veselovská, Petra ; Dreveňáková, Petra ; Rapantová, Barbora ; Klem, Karel
This study presents data points acquired during 2 years of measuring optical properties and gas-exchange\ncharacteristics of European beech (Fagus sylvatica) and Norway spruce (Picea abies) tree species in controlled\nenvironments. The observed statistical relationships between 105 pairs of selected optical parameters\n(i.e. photochemical reflectance index [PRI], ΔPRI, and normalized difference between wavebands R690\nand R630 [where R is a reflectance at a subscripted wavelength]) and light use efficiency (LUE) were considered\nat assumed different canopy leaf area index, changing pigments stoichiometrics, and daily changing\ndynamics of environmental conditions. Our measurements suggested that consistency of the LUE estimation\nusing PRI may be disrupted by acclimation responses of plants that reduce energetic carriers for\nuse in photosynthetic CO2 uptake and the xanthophyll cycle. Also, a changing chlorophylls-to-carotenoids\nratio tends to interrupt the PRI–LUE relationship. ΔPRI showed sensitivity to leaf area index of the measured\ntrees that complicated leaf-level estimation of LUE. The most consistent assessment of LUE was\nachieved using the chlorophyll fluorescence detecting ratio (R690 – R630)/(R690 + R630).
Land cover change detection on the agriculture land
Klouček, Tomáš ; Štych, Přemysl (advisor) ; Brodský, Lukáš (referee)
The main purpose of thesis is creation and evaluation of models for change detection of arable land to grassland by Hybrid-based Change Detection method, which combined approaches based on the Vegetation Indices, Image Differencing and Principal Component Analysis. Six locations with different seasonal configuration of images with high resolution and one locality covered by image with very high resolution were used. The areas were spread across the foothill areas of the Czech Republic. The selection of predictors and the most suitable model was supported by statistical calculation. Application selected models were carried out using a multi-temporal object classification and their accuracy were verified using reference data. The benefit of this thesis is finding generally applicable model useful to investigate the land cover change and evaluation of the potentially most appropriate seasonal configuration of images. Valuable is also methodology in this thesis which focus on selection of predictors and calculation the order of the most appropriate models, which is unique in the available literature. The thesis provides useful findings fitting to insufficiently explored issue of Change Detection arable land to grassland. Powered by TCPDF (www.tcpdf.org)
Evalution of Time Series of Satellite Images to Observe Disturbancec in the Low Tatras
Laštovička, Josef ; Štych, Přemysl (advisor) ; Hais, Martin (referee)
The work is aimed at finding appropriate methods for observing changes in the status of forest vegetation and its evaluation in the years 1992-2015. The satellite images of the Low Tatras are analyzed by using Time Series technology. Specifically, the images Landsat 4, 5, 7 and 8, for which it is necessary to perform a calibration and an adjustment of input data values to realize the individual vegetation indices, due to the fact that the images are captured by different sensors with different radiometric resolution. From this perspective, the work deals with the possibilities of normalized relative radiometric corrections and search for a particular type of appropriate compensation for Landsat CDR images. Calibrated data sets are evaluated by Time Series of different vegetation indices. The resulting values are evaluated in relation with the occurrence of forest disturbances, eg. wind storms, biological and other pests. The final part is discussion of the results, evaluating the test methods of calibration and suitability of vegetation indices for observing the state of calamity. The App is created for generating the Time Series of Landsat images CDR and for preparing RRN datasets. Key words: Time Series, radiometric correction, atmospheric correction, Landsat CDR, vegetation indices,...
Development of selected invasive species and meadow vegetation classification algorithm in the Krkonoše Mountains using hyperspectral data
Jelének, Jan ; Kupková, Lucie (advisor) ; Halabuk, Andrej (referee)
Development of selected invasive species and meadow vegetation classification algorithm in the Krkonoše Mountains using hyperspectral data Abstract The thesis deals with utilization of airbone APEX hyperspectral image data for selected invasive species and meadow vegetation classification in the study area of the Krkonoše Mountains National Park. The mian goal of the thesis was to develop of classification algorithm based on proposed vegetation indices. The approach was based on the utilization of in-situ LAI, fAPAR, chlorophyll content data and analysis of their relation with vegetation spectral properties. The work also deals with several problems regarding LAI - vegetation indices relationship, namely saturation of LAI and mutual correlation of LAI and chlorophyll content. Tha classification was focued on invasive species Rumex alpinus and Lupinus polyphyllus, meadow vegetation with dominant Nardus stricta and dominant Trisetum flavescens and cutted lawns. Besides the proposed approach, the presented work resulted in several classification maps of study area and in spectral libraries, containing ground level spectra of studied invasive species, meadow vegetation types and several other meadow species. Keywords: hyperspectral image data, APEX, LAI, fAPAR, vegetation indices, invasive species, meadow...
The use of vegetation indices to study temporal variation in vegetation phenology
Beránková, Petra ; Štych, Přemysl (advisor) ; Hesslerová, Petra (referee)
1 ABSTRACT The work deals with the use of vegetation indices to study temporal variation in vegetation phenology. The first part was devoted to detailed analysis of domestic and foreign literature, which deals with the work processed in this field. The main research questions were if changed start, end and length of growing period during the analysis period. Other research theme was comparision with ground phenological data. Another objective of this work was search dependencies computed data phenological variables from vegetation indicies with phenological ground data. As a basic data set was used GIMMS set, which distributes the vegetation index NDVI. Other data sets were MERIS MTCI, data MODIS with vegetation indices NDVI, EVI a LAI. The results of analyzes of vegetation phenology show trends in most shifts at the beginning of growing season, where was a shift to an earlier time. Results of the analysis of vegetation remote sensing data with ground-based phenological data ČHMÚ were unfolding always according to the specific forest phenological stations. Interesting results were at the phenological station Svoboda nad Úpou, where the results of trends directives were consistent in almost all data sets. Comparison of process curves vegetation indicies with ground data corresponded most curves at selected...
Evaluation of forest calamites using the remote sensing data
Chrást, Josef ; Štych, Přemysl (advisor) ; Jedlička, Jan (referee)
Evaluation of forest calamities using the remote sensing data Abstract The objective of this paper is to evaluate possibilities of medium-spatial resolution satellite data assimilation for monitoring of the forest disturbances. The aim of the study is to monitore the bark beetle outbreak in the Šumava Mountains. For this purpose were used eight MERIS scenes from 2002 to 2009. Spectral response of the damaged spruce stands has been analyzed on the based of the values of selected vegetation indices (NDVI, LAI, LAI.Cab, fCover, fAPAR and three newly defined indices) and their temporal progress. The results were compared with values for healthy forests. The values of spectral indices have shown the ability of data MERIS to monitor forest disturbances at regionale scale.
Prediction of crop yields using satellite remote sensing
Lukas, V. ; Trnka, Miroslav ; Semerádová, Daniela ; Rajdl, Kamil ; Balek, Jan ; Štěpánek, Petr ; Zahradníček, Pavel ; Hlavinka, Petr ; Žalud, Zdeněk
Knowledge of the crop yield with sufficient lead time prior to harvest is crucial for both the farm management and the agro-food sector policy. The aim of this study was to test feasibility of developing crop yield forecasting model in Czech Republic for winter wheat, spring barley and oilseed rape based on 2000-2014 database of vegetation indices Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI2) from Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra satellite in form of 16-days composites. An average yield data were collected for 14 selected districts in the Czech Republic that represent the regions with more intensive agricultural production among varying climate and topographic conditions. The viability of the concept was proven in years with significant yield decline i.e. 2000, 2003, 2006 and 2012, when yields of cereals were significantly affected by occurred drought periods. More stable regression results were achieved in the most productive areas such as Olomouc and Prerov, whilst models in highland regions were influenced by lower acreage of three modelled crops and higher prevalence of fodder crops. In most cases, EVI2 showed higher correlations to the crop yield together with using an average value of all composites during vegetation period.
Remote sensing as support tool for agricultural drought assessment
Hlavinka, Petr ; Semerádová, Daniela ; Balek, Jan ; Žalud, Z. ; Tadesse, T. ; Hayes, M. ; Wardlow, B. ; Trnka, Miroslav
Very important information about vegetation condition within wide areas (through continents and states) or for local areas in resolution from hundreds to tens of meters could be obtained from satellites within remote sensing. The temporal and spatial continuity is big advantage of this method. Namely so-called vegetation indices are often used for vegetation cover condition assessment. The aim of submitted study is to present possibility of using EVI2 (Enhanced Vegetation Index) for assessment of drought impact within vegetation. The results for selected years of the period 2000-2015 achieved using MODIS (Moderate Resolution Imaging Spectroradiometer) aboard Terra satellite are included. The data in weekly time step and for the whole Czech Republic are presented.

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