Application of airborne lidar in high precision surveying and mapping of tidal flats

2014 ◽  
Author(s):  
X.D. Wen ◽  
S.Y. Wang ◽  
Y. Lin
Keyword(s):  
High Precision ◽  
Tidal Flats ◽  
Airborne Lidar ◽  
Surveying And Mapping

scholarly journals Experimental Comparison of Outdoor Baseline Measurements by Different Methods

2019 ◽  
Vol 131 ◽  
pp. 01057
Author(s):  
Youyi Gu ◽  
Li Wang ◽  
Fengzhuo Xiang ◽  
Wen Ouyang ◽  
Lixing Jiang
Keyword(s):  
Direct Measurement ◽  
High Precision ◽  
Optical Measurement ◽  
Experimental Results ◽  
Experimental Comparison ◽  
Total Station ◽  
Length Standard ◽  
Gnss Receivers ◽  
Surveying And Mapping

Outdoor baseline is the special length standard in the field of surveying and mapping, it can be used to verify the addition and multiplication constants of the total station and other photoelectric rangefinders. In order to ensure the authenticity, accuracy and reliability of verification results, conducting outdoor baseline traceability periodically is essential. At present, direct measurement by 24m invar tape or high precision electro-optical measurement is mainly used to achieve the traceability of outdoor baseline in China. Based on Shenyang baseline field, high precision rangefinder μ-base, 24m invar tape and high precision GNSS receivers are used for comparison experiments, and the experimental results are analyzed.

High-precision DEM reconstruction based on airborne LiDAR point clouds

2014 ◽  
Author(s):  
Jingzhong Xu ◽  
Yuan Kou ◽  
Jun Wang
Keyword(s):  
High Precision ◽  
Point Clouds ◽  
Airborne Lidar

scholarly journals Preparation of High-Resolution DTM and Orthophoto Using LiDAR in Nepal

2020 ◽  
Vol 20 (1) ◽  
pp. 75-80
Author(s):  
Abhash Joshi ◽  
Sumeer Koirala
Keyword(s):  
Economic Development ◽  
High Resolution ◽  
Digital Terrain Model ◽  
Cost Effective ◽  
Interval Data ◽  
Development Planning ◽  
Airborne Lidar ◽  
Grid Data ◽  
Terrain Model ◽  
Surveying And Mapping

The high-resolution terrain model has varied usages including development planning, engineering works, environmental management, disaster management, urban planning, irrigation, geological study, archeological study and cadastral application. Currently, this data is not available for Nepal and it has also hindered the socio and economic development of the country. Airborne Lidar is economically cost-effective and viable means for topography related data collection. Lidar which is an acronym for Light Detection and Ranging is an active remote sensing technology in which Laser beams are used for surveying and mapping. The Survey Department of Nepal has taken initiative to prepare the High-Resolution DTM and Orthophoto of about 20,000 square kilometres of Nepal using Lidar surveying and mapping. Survey Department is conducting a LiDAR survey in the western terai regions of Nepal from Chitwan to Kanchanpur district. Airborne LiDAR survey data along with a very high resolution (0.15 m) orthophoto shall be generated. Further, processing of LiDAR points data will generate a highly precise digital terrain model of 1 m grid data having an accuracy of 0.25 m and finally 0.5 m contour interval data. This endeavor is one of the milestones in the surveying and mapping sector of Nepal and it will have far-reaching consequence in the social and economic development of Nepal.

scholarly journals A simple and feasible process for using multi-stage high-precision DTMs, field surveys and rainfall data to study debris flow occurrence factors of Shenmu area, Taiwan

2012 ◽  
Vol 12 (11) ◽  
pp. 3407-3419 ◽  
Author(s):  
W.-C. Lo ◽  
B.-S. Lin ◽  
H.-C. Ho ◽  
J. Keck ◽  
H.-Y. Yin ◽  
...  
Keyword(s):  
Debris Flow ◽  
High Precision ◽  
Debris Flows ◽  
Airborne Lidar ◽  
Rainfall Characteristics ◽  
Field Surveys ◽  
Sensing Technology ◽  
Multi Stage ◽  
Catchment Areas ◽  
Typhoon Herb

Abstract. The occurrence of typhoon Herb in 1996 caused massive landslides in the Shenmu area of Taiwan. Many people died and stream and river beds were covered by meters of debris. Debris flows almost always take place in the Shenmu area during the flood season, especially in the catchment areas around Tsushui river and Aiyuzih river. Anthropogenic and natural factors that cause debris flow occurrences are complex and numerous. The precise conditions of initiation are difficult to be identified, but three factors are generally considered to be the most important ones, i.e. rainfall characteristics, geologic conditions and topography. This study proposes a simple and feasible process that combines remote sensing technology and multi-stage high-precision DTMs from aerial orthoimages and airborne LiDAR with field surveys to establish a connection between three major occurrence factors that trigger debris flows in the Shenmu area.

scholarly journals A HIGH PRECISION DEM EXTRACTION METHOD BASED ON INSAR DATA

2018 ◽  
Vol IV-3 ◽  
pp. 211-216
Author(s):  
Xinshuang Wang ◽  
Lingling Liu ◽  
Xiaoliang Shi ◽  
Xitao Huang ◽  
Wei Geng
Keyword(s):  
High Precision ◽  
Interpolation Method ◽  
Shaanxi Province ◽  
Strong Positive Correlation ◽  
Ground Control Points ◽  
Data Processing Method ◽  
X Band ◽  
Correlation Information ◽  
Orbital Data ◽  
Surveying And Mapping

In the 13th Five-Year Plan for Geoinformatics Business, it is proposed that the new InSAR technology should be applied to surveying and mapping production, which will become the innovation driving force of geoinformatics industry. This paper will study closely around the new outline of surveying and mapping and then achieve the TerraSAR/TanDEM data of Bin County in Shaanxi Province in X band. The studying steps are as follows; Firstly, the baseline is estimated from the orbital data; Secondly, the interferometric pairs of SAR image are accurately registered; Thirdly, the interferogram is generated; Fourth, the interferometric correlation information is estimated and the flat-earth phase is removed. In order to solve the phase noise and the discontinuity phase existing in the interferometric image of phase, a GAMMA adaptive filtering method is adopted. Aiming at the "hole" problem of missing data in low coherent area, the interpolation method of low coherent area mask is used to assist the phase unwrapping. Then, the accuracy of the interferometric baseline is estimated from the ground control points. Finally, 1&amp;thinsp;:&amp;thinsp;50000&amp;thinsp;DEM is generated, and the existing DEM data is used to verify the accuracy through statistical analysis. The research results show that the improved InSAR data processing method in this paper can obtain the high-precision DEM of the study area, exactly the same with the topography of reference DEM. The R<sup>2</sup> can reach to 0.9648, showing a strong positive correlation.

scholarly journals Statistical Analysis for Tidal Flat Classification and Topography Using Multitemporal SAR Backscattering Coefficients

2021 ◽  
Vol 13 (24) ◽  
pp. 5169
Author(s):  
Keunyong Kim ◽  
Hahnchul Jung ◽  
Jong-Kuk Choi ◽  
Joo-Hyung Ryu
Keyword(s):  
Tidal Flat ◽  
Extraction Method ◽  
Morphological Changes ◽  
Logistic Function ◽  
Tidal Flats ◽  
Airborne Lidar ◽  
Small Scale ◽  
Spatial Coverage ◽  
Natural Break ◽  
Sar Data

Coastal zones are very dynamic natural systems that experience short-term and long-term morphological changes. Their highly dynamic behavior requires frequent monitoring. Tidal flat topography for a large spatial coverage has been generated mainly by the waterline extraction method from multitemporal remote sensing observations. Despite the efficiency and robustness of the waterline extraction method, the waterline-based digital elevation model (DEM) is limited to representing small scale topographic features, such as localized tidal tributaries. Tidal flats show a rapid increase in SAR backscattering coefficients when the tide height is lower than the tidal flat topography compared to when the tidal flat is covered by water. This leads to a tidal flat with a distinct statistical behavior on the temporal variability of our multitemporal SAR backscattering coefficients. Therefore, this study aims to suggest a new method that can overcome the constraints of the waterline-based method by using a pixel-based DEM generation algorithm. Jenks Natural Break (JNB) optimization was applied to distinguish the tidal flat from land and ocean using multitemporal Senitnel-1 SAR data for the years 2014–2020. We also implemented a logistic model to characterize the temporal evolution of the SAR backscattering coefficients along with the tide heights and estimated intertidal topography. The Sentinel-1 DEM from the JNB classification and logistic function was evaluated by an airborne Lidar DEM. Our pixel-based DEM outperformed the waterline-based Landsat DEM. This study demonstrates that our statistical approach to intertidal classification and topography serves to monitor the near real-time spatiotemporal distribution changes of tidal flats through continuous and stable SAR data collection on local and regional scales.

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