Accuracy Assessment of Mobile Laser Scanning Elevation Data in Different Vegetation Areas

2017 ◽  
Author(s):  
Kaupo Kokamägi ◽  
Natalja Liba ◽  
Kristo Must ◽  
Martin Sirk
Keyword(s):  
Laser Scanning ◽  
Accuracy Assessment ◽  
Objective Assessment ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Sparse Vegetation ◽  
Aerial Laser Scanning ◽  
Elevation Data ◽  
Global Navigation Satellite ◽  
Ground Profile

Due to the overall development of technology, laser scanning has reached a new level. During the last decade, all the different technologies necessary for mobile laser scanning, have been developed. Due to the fact that mobile laser scanning brings the need to process very large amounts of data, development of computers and software is also very important. The aim of current research was to assess the accuracy of mobile laser scanning elevation data in different vegetation areas and to explore if mobile laser scanning could be used as an alternative to aerial laser scanning. This article only covers the data collecting, processing and accuracy assessment aspects of the research. Data used in current study was collected in summer of 2015, during mobile laser scanning of Põltsamaa-Kärevere section of E263 route (Tallinn-Tartu-Võru-Luhamaa). Three smaller, differently vegetated, sections were picked from the large project to study the accuracy of elevation data. For accuracy assessment, the mobile laser scanning elevation data was compared to the checkpoints measured with GNSS (Global Navigation Satellite Systems) device. Ground profiles were drawn based on mobile laser scanning data. For objective assessment, accuracy of mobile laser scanning elevation data was compared to accuracy of ground profile elevation data and aerial laser scanning elevation data. The study found that the RMSE (Root Mean Square Error) in the I section, which was a field vegetated with 1 metre high crop, was 0,98 metres. RMSE in the II section, which was a pasture with low and sparse vegetation, was 0,23 metres. RMSE in the III section, which contained a bushy ditch and a field behind it, was 0,61 metres. Results show that the accuracy of mobile laser scanning elevation data depends substantially on the density of vegetation in scanned areas and that drawing ground profiles reduced the RMSE of mobile laser scanning elevation data. Results show that the accuracy of mobile laser scanning elevation data depends substantially on the density of vegetation in scanned areas. On this basis it can be concluded, that the most reasonable time to conduct mobile laser scanning would be during a season, when vegetation is the sparsest. It can also be concluded that drawing ground profiles makes mobile laser scanning data more accurate.

scholarly journals The Etruscans in 3D: From Space to Underground

2011 ◽  
Vol 6 ◽  
pp. 283-290 ◽  
Author(s):  
Fabio Remondino ◽  
Alessandro Rizzi ◽  
Belen Jimenez ◽  
Giorgio Agugiaro ◽  
Giorgio Baratti ◽  
...  
Keyword(s):  
Cultural Heritage ◽  
Information And Communication Technologies ◽  
Laser Scanning ◽  
Information Science ◽  
Geographic Information ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Heritage Sites ◽  
Museum Exhibitions ◽  
Global Navigation Satellite

eomatics and Geoinformatics deal with spatial and geographic information, 3D surveying and modeling as well as information science infrastructures. Geomatics and Geoinformatics are thus involved in cartography, mapping, photogrammetry, remote sensing, laser scanning, Geographic Information Systems (GIS), Global Navigation Satellite Systems (GNSS), geo-visualisation, geospatial data analysis and Cultural Heritage documentation. In particular the Cultural Heritage field can largely benefit from different Information and Communication Technologies (ICT) tools to make digital heritage information more informative for documentation and conservation issues, archaeological analyses or virtual museums. This work presents the 3D surveying and modeling of different Etruscan heritage sites with their underground frescoed tombs dating back to VII-IV century B.C.. The recorded and processed 3D data are used, beside digital conservation, preservation, transmission to future generations and studies purposes, to create digital contents for virtual visits, museum exhibitions, better access and communication of the heritage information, etc.

scholarly journals GEODESIC METHODS FOR CREATION OF UNIQUE GEOINFORMATION SPACE

2019 ◽  
Vol 1 (1) ◽  
pp. 173-183
Author(s):  
Sergey Gorobtsov ◽  
Vladimir Obidenko
Keyword(s):  
Laser Scanning ◽  
Spatial Information ◽  
Survey Methods ◽  
Essential Element ◽  
Global Navigation Satellite Systems ◽  
3D Laser Scanning ◽  
Foreign Markets ◽  
Satellite Systems ◽  
Ground Survey ◽  
Global Navigation Satellite

Modern geodesic support is an integral and essential element of the process of collecting spatial information. The article considers geodesic methods for creating a unique geoinformation space: digitization of cartographic materials, ground survey methods (electronic total stations, 3D laser scanning), remote sensing and methods of the global navigation satellite systems GLONASS and GPS. The article also contains recommended conversion options between the coordinate systems SK-95 and GSK-2011. A comparative analysis of the surveyed geodesic methods for geodata col-lection was carried out. Russian and foreign markets of specialized software for processing geodata are considered, appropriate conclusions are made.

scholarly journals KORTOWO TEST FIELD FOR TESTING PHOTOGRAMMETRIC PRODUCTS ACCURACY – DESIGN AND FIRST EVALUATION

2019 ◽  
Vol XLII-1/W2 ◽  
pp. 23-29
Author(s):  
G. Gabara ◽  
P. Sawicki
Keyword(s):  
Accuracy Assessment ◽  
Laser Scanner ◽  
Digital Camera ◽  
Point Clouds ◽  
Digital Processing ◽  
Global Navigation Satellite Systems ◽  
Test Field ◽  
Satellite Systems ◽  
3D Data ◽  
Global Navigation Satellite

<p><strong>Abstract.</strong> The continuous development of sensors, methods and technologies in the modern digital photogrammetry requires testing the quality and accuracy of software, processing workflow and products. The paper presents a new test field for performance analysis of software processing and accuracy assessment of photogrammetric 2D and 3D data collection, mapping, 3D object reconstruction and modeling based on low-altitude imagery with particular regard to unmanned aerial vehicles imagery. The first experiment was carried out using images captured by Phase One iXU-RS 1000 medium format aerial digital camera and Light Detection and Ranging (LiDAR) point cloud acquired by RIEGL LMS-Q680i airborne laser scanner. The process of complex digital processing was performed in Agisoft Metashape packages. The subblock of 169 images and 16 signalized ground points measured by Global Navigation Satellite Systems in the WGS 84 coordinate system using the Real-Time Network method were adopted in the preliminary investigations. The root mean square error RMSEXYZ on check points in the bundle block adjustment was equal to 0.032&amp;thinsp;m. Vertical deviations between digital elevation model and LiDAR point clouds belong to the range from &amp;minus;0.020&amp;thinsp;m to 0.020&amp;thinsp;m which is related to RIEGL LMS-Q680i accuracy and precision. Georeferenced orthomosaic was generated with ground sampling distance (GSD) equal to 0.020&amp;thinsp;m, which was the same as the GSD of input images. The high accuracy of obtained processing results is related to accuracy of initial data, and it proves the usefulness of Kortowo test field.</p>

The stochastic model for Global Navigation Satellite Systems and terrestrial laser scanning observations: A proposal to account for correlations in least squares adjustment

2019 ◽  
Vol 13 (2) ◽  
pp. 93-104 ◽  
Author(s):  
Gael Kermarrec ◽  
Ingo Neumann ◽  
Hamza Alkhatib ◽  
Steffen Schön
Keyword(s):  
Least Squares ◽  
Laser Scanning ◽  
Global Navigation Satellite Systems ◽  
Deformation Analysis ◽  
Navigation Satellite ◽  
Unknown Parameters ◽  
Satellite Systems ◽  
Unbiased Test ◽  
Global Navigation ◽  
Global Navigation Satellite

Abstract The best unbiased estimates of unknown parameters in linear models have the smallest expected mean-squared errors as long as the residuals are weighted with their true variance–covariance matrix. As this condition is rarely met in real applications, the least-squares (LS) estimator is less trustworthy and the parameter precision is often overoptimistic, particularly when correlations are neglected. A careful description of the physical and mathematical relationships between the observations is, thus, necessary to reach a realistic solution and unbiased test statistics. Global Navigation Satellite Systems and terrestrial laser scanners (TLS) measurements show similarities and can be both processed in LS adjustments, either for positioning or deformation analysis. Thus, a parallel between stochastic models for Global Navigation Satellite Systems observations proposed previously in the case of correlations and functions for TLS range measurements based on intensity values can be drawn. This comparison paves the way for a simplified way to account for correlations for a use in LS adjustment.

Hydrogeophysical Survey of Groundwater Development at Okada Community Ovia North – East L.G.A. Edo State

2018 ◽  
Vol 2 (1) ◽  
pp. 39-45
Author(s):  
M. O. Ehigiator
Keyword(s):  
Global Navigation Satellite Systems ◽  
Geophysical Investigation ◽  
Satellite Systems ◽  
North East ◽  
Long Time ◽  
Electrical Sounding ◽  
Edo State ◽  
Global Navigation Satellite ◽  
Water Problems ◽  
Aquifer Unit

Geophysical investigation was conducted at Okada community in ovia North Local Govertment area of Edo state to determine the prospect of aquifer zone. The Petrozenith PZ-02 Terrameter, one of the Electrical Resistivity Equipment was used to conduct a Vertical Electrical Sounding (VES) in the study area. The Garmin Etrex 10 Global Navigation satellite systems (GNSS) was used to acquire Geodetic coordinates of point where VES observations were made. This research was carried out as a pre-drilling Hydro-geophysical survey conducted for the purpose of surveying and studying the proposed water borehole site at Okada Community that has suffered acute water problems for a very long time. There have been series of boreholes drilled in the studied area but all are dry wells. This survey was conducted to investigate the subsurface complexity of the sites in respect of lithology and to recommend the total drill depth based on the prospective aquifer unit so identified. Result of interpretation suggests that the area is underlain with substantive aquiferous formation but at a depth not exceeding 121.60 m (398.95 ft), which is the lower aquifer unit. The value of elevation at point of observation referenced to mean sea level is 94 m.

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