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Snow cover detection from webcam images
Fišer, Jan ; Brodský, Lukáš (advisor) ; Jeníček, Michal (referee)
This thesis deals with the possibility of using webcams as a source of spatial data for snow occurrence. The aim of this study is to propose a suitable method of snow cover detection from web camera images. From a sample of 6 webcams of the Czech Hydrometeorological Institute (CHMI) the snow cover is detected by pixel classification methods. The effect of training file size on the accuracy of classification is examined and the overall accuracy achieved by the SVM method was shown to be 97.46%. This study also aims to propose a system for determining the proportion of snow-covered areas. The algorithm consists of several sub-steps: filtering and registration of images, detection of snow, introduction of a coordinate system, calculation of the size of the surveyed area and the proportion of snow-covered area. The designed model can be used for automatic processing of images for various webcams. The melting curves of the snow cover are generated from the obtained daily values of the snow covered area. The results are validated using data from selected CHMI stations. The proposed and parameterized model confirms the possibility of successful use of webcams as a complement to ground measurement of meteorological stations and for the validation of remote sensing products.
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Creating 3D models by a UAV
Marek, Robert ; Štefanová, Eva (advisor) ; Brodský, Lukáš (referee)
Bachelor thesis deals with the utilization of UAV for data collection for photogrammetric purposes. Its goal is to create 3D models from the data used by the UAV. These are processed in selected UAV softwares based on analysis. In addition to the basic principles of UAV photogrammetry, the theoretical part includes a search for appropriate methodology for the preparation and implementation of the flight mission. Data processing took place in the Pix4D, 3DSurvey, and the Reference Photoscan used for general visualization. The final part evaluates the resulting accuracy of the outputs. Selected softwares were compared from 16 different criteria, making the Pix4D software the most convenient for processing UAV data. The aim of the thesis is not only to point out the potential of UAV resources in visualization of spatial data, but also the softwares used for this specific data. Keywords UAV, UAV photogrammetry, 3D model, drone, Agisoft Photoscan, Pix4D, 3DSurvey
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Grassland management monitoring based on Sentinel-1 data
Doležal, Jan ; Potůčková, Markéta (advisor) ; Brodský, Lukáš (referee)
The main goal of this diploma thesis was to find and quantify the connection between coherence, entropy, polarimetric angle alpha obtained from Sentinel-1 radar data and grass cutting/pastures. The research was carried out in the area of the Krkonoše national park. To assemble and validate applied methodology, field data was collected 5 times. Hourly rainfall data from Czech hydrometeorological institute was available, but it did not have to be used - no rainfalls were recorded at the time of data acquisitions. Dependence between mowing and the value of coherence has been confirmed. After mowing, median coherence was higher than before mowing. The results were similar to VH as well as VV polarization. Coherence on polygons remained higher after 12-24 days. In total, two different data acquisition geometries (ascending and descending) were examined. The results in both cases were similar. For polarimetric parameters, no correlation between polarimetric parameters and grass mowing or pasture has been confirmed. Keywords: radar, SAR, Sentinel-1, coherence, polarimetry, grass mowing
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Creating 3D models by a UAV
Marek, Robert ; Štefanová, Eva (advisor) ; Brodský, Lukáš (referee)
The Thesis uses UAV to collect data for photogrammetric purposes. Its goal is to create 3D models from UAV data in selected software. These are applied based on the analysis of specific UAV-focused software. The theoretical part contains, besides the basic principles of UAV photogrammetry, a search for appropriate methodology for the preparation and implementation of the flight mission. Data processing took place in the Pix4D and 3DSurvey, compared to Agiosft Photoscan, used for general visualization. The resulting accuracy and quality of outputs is reviewed in the final section, where it is shown that UAV-specific softwares show greater accuracy of the model in position and space. The purpose of this research is to point out not only the potential of common UAV in visualization of spatial data, but also the software specific to these data. Keywords UAS, UAV photogrammetry, 3D model, Agisoft Photoscan, Pix4D, 3DSurvey
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Forest species determination from satellite data
Launer, Michal ; Kolář, Jan (advisor) ; Brodský, Lukáš (referee)
Forest species determination from satellite data Abstract This thesis examines the species composition of forests from satellite images using the pixel classification. The research was done on 24 forest locations in The Ustecký Region, The Karlovarský Region, The Plzeňský Region and The Central Bohemian Region in the Czech Republic. In this thesis, data from the Landsat-8 and Sentinel-2 satellites from summer season and the Random Forest Classifier method were used. The layer of species composition of forests from map portal LhpoMap was used as reference data. The method of work consisted of a broad literature search to select the most favourable classifier and to choose the most advantageous input parameter values to achieve the highest overall accuracy of the classification. The practical part was focused on creating a software classification process. The accuracy of the individual image values was verified using matrix errors. Based on the literature search, the Random Forest classifier was used to classify the images. Parameter values were used for the Gini criterion, 500 decision trees, and the other parameters were left with default values. The entire classification process was performed in ArcMap and ArcGIS Pro software using Python programming language with the help of the sklearn.ensemble module...
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Skin surface water temperatures determination in selected lakes and reservoirs from satellite data
Formánek, Tomáš ; Kolář, Jan (advisor) ; Brodský, Lukáš (referee)
LAKE SURFACE TEMPERATURE DETERMINED BY SATELLITE IMAGES Abstract The aim of this master thesis is to create a method to determine surface temperature of water in lake Osoyoos (LSWT - Lake Surface Water Temperature). It is necessary to know this temperature in order to make easier decisions in a paradigm of global warming processes. Thanks to LSWT it is possible to make a timeline visualisation of temperature development in years. The first chapter deals with a physical definition of how to get thermal information - the basis of remote thermal sensing is measuring of radiance intensity and it's transformation to brightness temperature. This radiation is not only influenced by atmospheric properties but also by local climatic and meteorological conditions, but it is also influenced by the relief. The thesis seeks to create a method for calculating surface temperature of lake Osoyoos located at Canadian-American border. This calculation is based on data provided by ASTER using a split-window method. The method works with the differences in bands of sensing in order to remove atmospheric influences. This thesis contains several charts, graphs and pictures. The final result of this paper is a map of distribution of lake surface water temperatures. Keywords: Thermal remote sensing, land surface temperature, ASTER, TIR
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