scholarly journals Quality parameters of digital aerial survey and airborne laser scanning covering the entire area of the Czech Republic

2013 ◽  
Vol 10 ◽  
pp. 15-26 ◽  
Author(s):  
Jiří Šíma
Keyword(s):  
Czech Republic ◽  
Laser Scanning ◽  
Aerial Survey ◽  
Systematic Investigation ◽  
Quality Parameters ◽  
Entire Area ◽  
The Czech Republic ◽  
Digital Elevation ◽  
Land Survey ◽  
The University

The paper illustrates the development of digital aerial survey and digital elevation models covering the entire area of the Czech Republic at the beginning of 21st century. It also presents some results of systematic investigation of their quality parameters reached by the author in cooperation with Department of Geomatics at the Faculty of Applied Sciences of the University of Western Bohemia in Pilsen and the Land Survey Office.

scholarly journals ANALYSIS OF INFLUENCE OF TERRAIN RELIEF ROUGHNESS ON DEM ACCURACY GENERATED FROM LIDAR IN THE CZECH REPUBLIC TERRITORY

2016 ◽  
Vol XLI-B4 ◽  
pp. 25-30 ◽  
Author(s):  
M. Hubacek ◽  
V. Kovarik ◽  
V. Kratochvil
Keyword(s):  
Czech Republic ◽  
Laser Scanning ◽  
Vegetation Coverage ◽  
The Czech Republic ◽  
Digital Elevation ◽  
Lower Accuracy ◽  
Check Points ◽  
Elevation Data ◽  
Dem Accuracy ◽  
Elevation Model

Digital elevation models are today a common part of geographic information systems and derived applications. The way of their creation is varied. It depends on the extent of area, required accuracy, delivery time, financial resources and technologies available. The first model covering the whole territory of the Czech Republic was created already in the early 1980's. Currently, the 5th DEM generation is being finished. Data collection for this model was realized using the airborne laser scanning which allowed creating the DEM of a new generation having the precision up to a decimetre. Model of such a precision expands the possibilities of employing the DEM and it also offers new opportunities for the use of elevation data especially in a domain of modelling the phenomena dependent on highly accurate data. The examples are precise modelling of hydrological phenomena, studying micro-relief objects, modelling the vehicle movement, detecting and describing historical changes of a landscape, designing constructions etc. <br><br> Due to a nature of the technology used for collecting data and generating DEM, it is assumed that the resulting model achieves lower accuracy in areas covered by vegetation and in built-up areas. Therefore the verification of model accuracy was carried out in five selected areas in Moravia. The network of check points was established using a total station in each area. To determine the reference heights of check points, the known geodetic points whose heights were defined using levelling were used. Up to several thousands of points were surveyed in each area. Individual points were selected according to a different configuration of relief, different surface types, and different vegetation coverage. The sets of deviations were obtained by comparing the DEM 5G heights with reference heights which was followed by verification of tested elevation model. Results of the analysis showed that the model reaches generally higher precision than the declared one in majority of areas. This applies in particular to areas covered by vegetation. By contrast, the larger deviations occurred in relation to the slope of the terrain, in particular in the micro-relief objects. The results are presented in this article.

scholarly journals ANALYSIS OF INFLUENCE OF TERRAIN RELIEF ROUGHNESS ON DEM ACCURACY GENERATED FROM LIDAR IN THE CZECH REPUBLIC TERRITORY

2016 ◽  
Vol XLI-B4 ◽  
pp. 25-30 ◽  
Author(s):  
M. Hubacek ◽  
V. Kovarik ◽  
V. Kratochvil
Keyword(s):  
Czech Republic ◽  
Laser Scanning ◽  
Vegetation Coverage ◽  
The Czech Republic ◽  
Digital Elevation ◽  
Lower Accuracy ◽  
Check Points ◽  
Elevation Data ◽  
Dem Accuracy ◽  
Elevation Model

Digital elevation models are today a common part of geographic information systems and derived applications. The way of their creation is varied. It depends on the extent of area, required accuracy, delivery time, financial resources and technologies available. The first model covering the whole territory of the Czech Republic was created already in the early 1980's. Currently, the 5th DEM generation is being finished. Data collection for this model was realized using the airborne laser scanning which allowed creating the DEM of a new generation having the precision up to a decimetre. Model of such a precision expands the possibilities of employing the DEM and it also offers new opportunities for the use of elevation data especially in a domain of modelling the phenomena dependent on highly accurate data. The examples are precise modelling of hydrological phenomena, studying micro-relief objects, modelling the vehicle movement, detecting and describing historical changes of a landscape, designing constructions etc. &lt;br&gt;&lt;br&gt; Due to a nature of the technology used for collecting data and generating DEM, it is assumed that the resulting model achieves lower accuracy in areas covered by vegetation and in built-up areas. Therefore the verification of model accuracy was carried out in five selected areas in Moravia. The network of check points was established using a total station in each area. To determine the reference heights of check points, the known geodetic points whose heights were defined using levelling were used. Up to several thousands of points were surveyed in each area. Individual points were selected according to a different configuration of relief, different surface types, and different vegetation coverage. The sets of deviations were obtained by comparing the DEM 5G heights with reference heights which was followed by verification of tested elevation model. Results of the analysis showed that the model reaches generally higher precision than the declared one in majority of areas. This applies in particular to areas covered by vegetation. By contrast, the larger deviations occurred in relation to the slope of the terrain, in particular in the micro-relief objects. The results are presented in this article.

scholarly journals Exploitation of Countrywide Airborne Lidar Dataset for Documentation of Historical Human Activities in Countryside

2011 ◽  
Vol 6 ◽  
pp. 97-102
Author(s):  
Petr Dušánek
Keyword(s):  
Czech Republic ◽  
Human Activities ◽  
Laser Scanning ◽  
Cultural Landscape ◽  
Digital Terrain Model ◽  
Airborne Lidar ◽  
Mining Activities ◽  
Data Set ◽  
Entire Area ◽  
The Czech Republic

During three years (2010 – 12) The Czech Office for Surveying, Mapping and Cadastre in cooperation with The Ministry of Defense of the Czech Republic and The Ministry of Agriculture of the Czech Republic are providing mapping of the entire area of the Czech Republic by Airborne laser scanning (ALS) technology. The goal of this project is to derive a highly accurate Digital Terrain Model (DTM) for purposes of administration like detection of flooded areas, orthorectification of areal images etc. Such data set also seems to be an interesting da ta source for mapping of human activities in countryside. Human settlements, agriculture or mining activities left significant scars on natural landscape. These significant man-made structures are a part of so called cultural landscape. Man-made structures include ancient settlements, remains of medieval mining activities or remains of settlements abandoned during 20th century. This article generally presents how to derive information about the man-made structures from raw LiDAR. Examples of significant findings of man-made imprints in countryside are also presented. Goal of this article is not to describe a certain archeological site but to inform about strengths of ALS data to map human activities in countryside, mainly in forested areas.

Designing on the New Elevation Database of the Czech Republic

2017 ◽  
Vol 755 ◽  
pp. 333-339 ◽  
Author(s):  
Jan Sobotka
Keyword(s):  
Czech Republic ◽  
Laser Scanning ◽  
Airborne Laser Scanning ◽  
The Czech Republic ◽  
Airborne Laser ◽  
Digital Elevation ◽  
Elevation Data

The article presents new possibilities of earthworks designing on new elevation data of the Czech Republic. These new elevation data are the result of the airborne laser scanning of the Czech Republic, which replace the old one. The new digital elevation database is another source of elevation data, which can be used during earthworks designing. Furthermore, the paper presents two projects, where new elevation data were used in practice.

scholarly journals PREPARATION OF THE DIGITAL ELEVATION MODEL FOR ORTHOPHOTO CR PRODUCTION

2016 ◽  
Vol XLI-B3 ◽  
pp. 107-113
Author(s):  
Z. Švec ◽  
K. Pavelka
Keyword(s):  
Czech Republic ◽  
Rural Areas ◽  
Laser Scanning ◽  
The State ◽  
Image Correlation ◽  
Aerial Photographs ◽  
Surface Model ◽  
Entire Area ◽  
The Czech Republic ◽  
Elevation Model

The Orthophoto CR is produced in co-operation with the Land Survey Office and the Military Geographical and Hydrometeorological Office. The product serves to ensure a defence of the state, integrated crisis management, civilian tasks in support of the state administration and the local self-government of the Czech Republic as well. It covers the whole area of the Republic and for ensuring its up-to-datedness is reproduced in the biennial period. As the project is countrywide, it keeps the project within the same parameters in urban and rural areas as well. Due to economic reasons it can´t be produced as a true ortophoto because it requires large side and forward overlaps of the aerial photographs and a preparation of the digital surface model instead of the digital terrain model. Use of DTM without some objects of DSM for orthogonalization purposes cause undesirable image deformations in the Orthophoto. There are a few data sets available for forming a suitable elevation model. The principal source should represent DTMs made from data acquired by the airborne laser scanning of the entire area of the Czech Republic that was carried out in the years 2009-2013, the DMR4G in the grid form and the DMR5G in TIN form respectively. It can be replenished by some vector objects (bridges, dams, etc.) taken from the geographic base data of the Czech Republic or obtained by new stereo plotting. It has to be taken into account that the option of applying DSM made from image correlation is also available. The article focuses on the possibilities of DTM supplement for ortogonalization. It looks back to the recent transition from grid to hybrid elevation models, problems that occurred, its solution and getting some practical remarks. Afterwards it assesses the current state and deals with the options for updating the model. Some accuracy analysis are included.

scholarly journals Detection of Microrelief Objects to Impede the Movement of Vehicles in Terrain

2019 ◽  
Vol 8 (3) ◽  
pp. 101 ◽  
Author(s):  
Filip Dohnal ◽  
Martin Hubacek ◽  
Katerina Simkova
Keyword(s):  
Czech Republic ◽  
Laser Scanning ◽  
Large Scale ◽  
High Reliability ◽  
Digital Elevation Models ◽  
Modeling Tools ◽  
The Czech Republic ◽  
Technical Parameters ◽  
Gis Tools ◽  
Digital Elevation

Relief of terrain as a part of the landscape greatly affects the possibilities of vehicles moving off the road. The main influence on the movement is the slope of terrain and the occurrence of microrelief objects. While the slope limits can be easily modeled in the GIS environment, it is difficult to express the effect of the microrelief on the possibilities of moving vehicles. The aim of this work was to find procedures for identification of impassable microrelief objects using GIS tools and precise digital elevation models. Technical parameters defining the ability of a vehicle to overcome microrelief objects are known and these are mainly defined by the dimensions of the vehicle such as a wheel base, a ground clearance, approach angle, and others. Large-scale digital elevation models have not been able to reliably express the location and shape of microrelief objects until recently. Their accuracy of height in nodes achieved meter or decimeter values. The change occurred with the use of airborne laser scanning technology for digital elevation model creation. The accuracy of models created using this technology achieves centimeter values. These can be used for detection of microrelief objects. One of these models is the DMR5 from the territory of the Czech Republic. Its declared total mean height error is 0.18 meters. This model, together with the GIS tools and the technical parameters of individual vehicles, was used to search for such microrelief objects that act as a barrier to movement. Procedures for detecting impassable microrelief objects were created by ArcGIS tools. Modeling tools and mathematical methods were used to create procedures for detection of microrelief objects. These have been applied to selected locations in the Czech Republic. Raster layers representing individual impassable microrelief objects are the result of modeling. The modeling results were verified in the terrain using military vehicles. Field tests confirmed the high reliability of the proposed procedure. Therefore, the calculation process was optimized and will be introduced in the future as one of the input calculations of the complex model of passability in the Army of the Czech Republic.

scholarly journals PREPARATION OF THE DIGITAL ELEVATION MODEL FOR ORTHOPHOTO CR PRODUCTION

2016 ◽  
Vol XLI-B3 ◽  
pp. 107-113
Author(s):  
Z. Švec ◽  
K. Pavelka
Keyword(s):  
Czech Republic ◽  
Rural Areas ◽  
Laser Scanning ◽  
The State ◽  
Image Correlation ◽  
Aerial Photographs ◽  
Surface Model ◽  
Entire Area ◽  
The Czech Republic ◽  
Elevation Model

The Orthophoto CR is produced in co-operation with the Land Survey Office and the Military Geographical and Hydrometeorological Office. The product serves to ensure a defence of the state, integrated crisis management, civilian tasks in support of the state administration and the local self-government of the Czech Republic as well. It covers the whole area of the Republic and for ensuring its up-to-datedness is reproduced in the biennial period. As the project is countrywide, it keeps the project within the same parameters in urban and rural areas as well. Due to economic reasons it can´t be produced as a true ortophoto because it requires large side and forward overlaps of the aerial photographs and a preparation of the digital surface model instead of the digital terrain model. Use of DTM without some objects of DSM for orthogonalization purposes cause undesirable image deformations in the Orthophoto. There are a few data sets available for forming a suitable elevation model. The principal source should represent DTMs made from data acquired by the airborne laser scanning of the entire area of the Czech Republic that was carried out in the years 2009-2013, the DMR4G in the grid form and the DMR5G in TIN form respectively. It can be replenished by some vector objects (bridges, dams, etc.) taken from the geographic base data of the Czech Republic or obtained by new stereo plotting. It has to be taken into account that the option of applying DSM made from image correlation is also available. The article focuses on the possibilities of DTM supplement for ortogonalization. It looks back to the recent transition from grid to hybrid elevation models, problems that occurred, its solution and getting some practical remarks. Afterwards it assesses the current state and deals with the options for updating the model. Some accuracy analysis are included.

scholarly journals The Assessment of Level of Flash Floods Threat of Urbanised Areas

2017 ◽  
Vol 65 (2) ◽  
pp. 519-526 ◽  
Author(s):  
Pavla Štěpánková ◽  
Miroslav Dumbrovský ◽  
Karel Drbal
Keyword(s):  
Czech Republic ◽  
Urban Areas ◽  
Flood Hazard ◽  
Flash Floods ◽  
Flood Risk Assessment ◽  
Entire Area ◽  
The Czech Republic ◽  
Eu Directive ◽  
Run Off ◽  
Technical Measures

Flash floods (or torrential rain flooding) is another type of flood hazard which has caused casualties and significant property damages. A methodology for identification of urban areas, which can potentially be burdened by that type of flood hazard, was proposed. This method, also called Method of Critical Points (CP), is a repeatable process able to identify areas, which are significant in terms of formation of surface run‑off and erosion. As addition to the preliminary flood risk assessment according to EU Directive 2007/60/ES on the Assessment and Management of Flood Risks, the presented methodology was applied for the entire area of the Czech Republic and the results are being used for the updating of non‑technical measures, e.g. urban planning. In the article, the principles of methodology of CP are described and results of the first application in the Czech Republic are presented, as well as possible interpretations of them.

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