National Repository of Grey Literature 68 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Detection of overhangs from airborne laserscanning data
Ondrušková, Kateřina ; Lysák, Jakub (advisor) ; Potůčková, Markéta (referee)
Detection of overhangs from airborne laserscanning data Abstract The objective of this thesis is to propose a method of processing airborne laserscanning data that include areas with overhangs with the goal of creating 2,5D digital terrain models. The theoretical part consists of brief introduction of basic principles of airborne laserscanning, followed by research of existing published solutions dealing with the problem of overhangs in airborne laserscanning data. Last section of theoretical part of the thesis deals with the usage of airborne laserscanning data in Czechia and digital terrain models created from those data are introduced. In practical part of the thesis, own method of processing of ALS data in the areas of overhangs is presented. The designed algorithm is then implemented in a form of script for ArcGIS 10 and the results are tested using real data from Czech Switzerland. The conclusion focuses on critical evaluation of the suggested method and its implementation. Keywords: overhangs, airborne laserscanning, digital terrain model
Training and validation dataset optimization for Earth observation classification accuracy improvement
Potočná, Barbora ; Kupková, Lucie (advisor) ; Potůčková, Markéta (referee)
This thesis deals with training dataset and validation dataset for Earth observation classification accuracy improvement. Experiments with training data and validation data for two classification algorithms (Maximum Likelihood - MLC and Support Vector Machine - SVM) are carried out from the forest-meadow landscape located in the foothill of the Giant Mountains (Podkrkonoší). The thesis is base on the assumption that 1/3 of training data and 2/3 of validation data is an ideal ratio to achieve maximal classification accuracy (Foody, 2009). Another hypothesis was that in a case of SVM classification, a lower number of training point is required to achieve the same or similar accuracy of classification, as in the case of the MLC algorithm (Foody, 2004). The main goal of the thesis was to test the influence of proportion / amount of training and validation data on the classification accuracy of Sentinel - 2A multispectral data using the MLC algorithm. The highest overal accuracy using the MLC classification algorithm was achieved for 375 training and 625 validation points. The overal accuracy for this ratio was 72,88 %. The theory of Foody (2009) that 1/3 of training data and 2/3 of validation data is an ideal ratio to achieve the highest classification accuracy, was confirmed by the overal accuracy and...
Classification of selected agricultural crops from time series of Sentinel-2 and PlanetScope imagery in Kutnohorsko model area
Kuthan, Tomáš ; Kupková, Lucie (advisor) ; Potůčková, Markéta (referee)
Classification of selected agricultural crops from time series of Sentinel-2 and PlanetScope imagery in Kutnohorsko model area Abstract The thesis is focused on the analysis of spectral characteristics of selected agricultural crops druring agriculutural season from time series of Sentinel -2 (A and B) and PlanetScope sensors in the model area situated around the settlements of Kolín and Kutná Hora. It is based on the assumption that the use of multiple dates of image data acquired crops in different phenological phases of the crops allows better identification of crop species (Lu et al., 2004). The aim of the thesis was to analyse the characteristics of the seasonal course of spectral features of selected agricultural crops (sugar beet, spring barley, winter barley, maize, spring wheat, winter wheat, winter rape) and to determine the period of the year suitable for the differentiation of individual crops. Another aim of the thesis was to classify these crops in the model area from time series of two above-mentioned sensors and to compare the accuracy of the pixel and object-oriented classification approach for multitemporal composites and the accuracy for monotemporal image from the term when the individual crops are clearly distinguishable. The training and validation datasets and the classification mask...
Filtration of Airborne Laserscanning Data
Jančovič, Marián ; Lysák, Jakub (advisor) ; Potůčková, Markéta (referee)
Filtration of Airborne Laserscanning Data Abstract The diploma thesis deals with automatized area classification with different surfaces in rocky towns. These areas are input into Airborne Laser-Scanning data filtration, where each of the areas is filtered with different parameters. The reason for this approach is the extreme height variety and dense vegetation typical for rocky towns, which causes the inadequacy of most common filtration algorithms applied with the same set of parameters for whole area. The methodic proposed by us consists of splitting the area of interest into three parts: Residential area, rocky area and area of vegetation (i.e. area that doesn't contain rocks or buildings). Each of these has special parameters applied during the following filtration, which reflect its characteristics. Key words: laser scanning, DTM, rocky towns, area based filtration
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
GIS application methods in antropology
Bashir, Faraz Ahmed ; Štefanová, Eva (advisor) ; Potůčková, Markéta (referee)
This bachelor thesis aims to use of geoinformatic methods in anthropology. Specifically methods of terrestrial laser scanning and close range photogrammetry. The theoretical part focuses on explaining functioning and usage of those methods. Practical part of this work discribes data collecting proces with those methods and following creation of 3D model of anthroplogical artifact, specifically human skull. In the end those models are compared with model from computed tomography which was provided, same as anthropological artifact, by Department of anthropology and human gentetics of Charles University.
Classification of Airborne Laser Scanning Data in Sandstone Landscapes
Tomková, Michaela ; Lysák, Jakub (advisor) ; Potůčková, Markéta (referee)
Classification of Airborne Laser Scanning Data in Sandstone Landscapes Abstract This work is concerned with the classification of airborne laser scanning data in sandstone landscapes called "rock cities". Standard filters do not work reliably in such a rugged terrain covered with dense vegetation and in the results the rock formations are smoothed or even removed from the terrain. The method of classification suggested in this work is based on the procedure used in manual filtration. When exploring a sufficiently dense point cloud in 3D, one is able to distinguish rock formations from trees even though their shapes are similar. In contrast to trees, rock pillars are modeled only by points reflected off the surface and therefore they make concave elevations in the ground. Because of penetration of trees, there are points reflected off a treetop, branches, leaves and also ground under the tree. The proposed method segments a point cloud according to local minima in approximated surface and classifies these objects into classes rock, tree, and mix by inner point distribution. Objects in classes tree and mix are then filtered by lasground function from LAStools. The method was tested with merged point cloud consisted of data from the standard airborne laser scanning of the Czech Republic and experimental...

National Repository of Grey Literature : 68 records found   1 - 10nextend  jump to record:
See also: similar author names
1 POTŮČKOVÁ, Magdaléna
3 Potůčková, Marie
2 Potůčková, Martina
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