Karel Charvat

Dr. Karel Charvat

Plan4all z.s., K Rybníčku 557, 33012 Horní Bříza, Czech Republic
orcid

Research Focus & Metrics

Academic Career Length

32Years (1995-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
Verified
Journal Article
Open access
PDF file
Tomas ReznikTomas Reznik
Tomas Reznik
VLVojtech Lukas
Vojtech Lukas
Karel CharvatKarel Charvat
Karel Charvat
KCKarel Charvát
Karel Charvát
ZKZbyněk Křivánek
Zbyněk Křivánek
HŘHelena Řezníková
Helena Řezníková
Intensive farming on land represents an increased burden on the environment due to, among other reasons, the usage of agrochemicals. Precision farming can reduce the environmental burden by employing site specific crop management practices which implement advanced geospatial technologies for respecting soil heterogeneity. The objectives of this paper are to present the frontier approaches of geospatial (Big) data processing based on satellite and sensor data which both aim at the prevention and mitigation phases of disaster risk reduction in agriculture. Three techniques are presented in order to demonstrate the possibilities of geospatial (Big) data collection in agriculture: (1) farm machinery telemetry for providing data about machinery operations on fields through the developed MapLogAgri application; (2) agrometeorological observation in the form of a wireless sensor network together with the SensLog solution for storing, analysing, and publishing sensor data; and (3) remote sensing for monitoring field spatial variability and crop status by means of freely-available high resolution satellite imagery. The benefits of re-using the techniques in disaster risk reduction processes are discussed. The conducted tests demonstrated the transferability of agricultural techniques to crisis/emergency management domains.

23 February 2022 in Remote Sensing
Verified
Journal Article
Open access
PDF file
HŠHeřman Šnevajs
Heřman Šnevajs
Karel CharvatKarel Charvat
Karel Charvat
VOVincent Onckelet
Vincent Onckelet
JKJiri Kvapil
Jiri Kvapil
FZFrantisek Zadrazil
Frantisek Zadrazil
IBIva Batrlova
Iva Batrlova
Satellite crop detection technologies are focused on the detection of different types of crops in fields. The information of crop-type area is more useful for food security than the earlier phenology stage is. Currently, data obtained from remote sensing (RS) are used to solve tasks related to the identification of the type of agricultural crops; additionally, modern technologies using AI methods are desired in the postprocessing stage. In this paper, we develop a methodology for the supervised classification of time series of Sentinel-2 and Sentinel-1 data, compare the accuracies based on different input datasets and find how the accuracy of classification develops during the season. In the EU, a unified Land Parcel Identification System (LPIS) is available to provide essential field borders. To increase usability, we also provide a classification of the entire field. This field classification also improves overall accuracy.

1 July 2018
Verified
Conference Paper
Closed access
Karel CharvatKarel Charvat
Karel Charvat
KJKarel Charvat Junior
Karel Charvat Junior
Tomas ReznikTomas Reznik
Tomas Reznik
VLVojtech Lukas
Vojtech Lukas
KJKarel Jedlicka
Karel Jedlicka
RBRaitis Berzins
Raitis Berzins
There is an increasing tension in agriculture between the requirements to assure full safety on the one hand and keep costs under control on the other hand, both with respect to (inter)national strategies. Farmers need to measure and understand the impact of huge amount and variety of data which drive overall quality and yield in their fields. Among others, those are local weather data, Global Navigation System of Systems data, orthophotos and satellite imagery, data on soil specifics etc. A strong need to secure Big Data arises due to various repositories and heterogeneous sources. Data storage and visualisation requirements are in some cases competing as they are a common interest as well as a threat that helps one part of a value chain to gain a higher profit. As demonstrated in this paper, handling (Big) data is therefore a sensitive topic, where trust of producers on data security is essential.

1 January 2015
Verified
Conference Paper
Open access
PDF file
TRTomáš Rezník
Tomáš Rezník
Karel CharvatKarel Charvat
Karel Charvat
VLVojtech Lukas
Vojtech Lukas
KJKarel Charvát Jr.
Karel Charvát Jr.
ŠHŠárka Horáková
Šárka Horáková
MKMichal Kepka
Michal Kepka

Verified
Journal Article
Open access
PDF file
SPStanislav Popelka
Stanislav Popelka
LHLukáš Herman
Lukáš Herman
Tomas ReznikTomas Reznik
Tomas Reznik
MPMichaela Pařilová
Michaela Pařilová
KJKarel Jedlicka
Karel Jedlicka
Karel CharvatKarel Charvat
Karel Charvat
Big data have also become a big challenge for cartographers, as the majority of big data may be localized. The use of visual analytics tools, as well as comprising interactive maps, stimulates inter-disciplinary actors to explore new ideas and decision-making methods. This paper deals with the evaluation of three map-based visual analytics tools by means of the eye-tracking method. The conceptual part of the paper begins with an analysis of the state-of-the-art and ends with the design of proof-of-concept experiments. The verification part consists of the design, composition, and realization of the conducted eye-tracking experiment, in which three map-based visual analytics tools were tested in terms of user-friendliness. A set of recommendations on GUI (graphical user interface) design and interactive functionality for map makers is formulated on the basis of the discovered errors and shortcomings in the assessed stimuli. The results of the verification were used as inputs for improving the three tested map-based visual analytics tools and might serve as a best practice for map-based visual analytics tools in general, as well as for improving the policy making cycle as elaborated by the European project PoliVisu (Policy Development based on Advanced Geospatial Data Analytics and Visualization).

20 April 2016
Verified
Book Chapter
Closed access
PDF file
RPRaúl Palma
Raúl Palma
Tomas ReznikTomas Reznik
Tomas Reznik
MEMiguel Esbrí
Miguel Esbrí
Karel CharvatKarel Charvat
Karel Charvat
Cezary MazurekCezary Mazurek
Cezary Mazurek