scholarly journals LiDAR with Pulsed Time of Flight

2021 ◽  
Author(s):  
S M Nazmuz Sakib
Keyword(s):  
Laser Scanning ◽  
Time Of Flight ◽  
Airborne Laser Scanning ◽  
Data Sets ◽  
Forest Assessment ◽  
Airborne Laser ◽  
Landscape Mapping ◽  
Research Findings ◽  
Assessment And Monitoring ◽  
Vegetation Measurement

LIDAR data has proved useful in recent years since it gives information such as item height and attributes, statistics over large regions, and it all becomes available by capturing the intensity of backscattered pulses in addition to 3D coordinates. “A LiDAR may generate a 2D angle image as well as a 3D picture containing angle/angle/range information. A LiDAR can directly measure range in each pixel since it controls when light is emitted, allowing it to calculate range based on the time of flight (ToF) to and from the object in a particular pixel. If there is enough signal, a 3D picture can also have grayscale and colour”. Coherent LiDAR can detect velocity quite precisely. Brief descriptions of airborne laser scanning technology [also known as "light detection and ranging" (LIDAR)] and research findings on its application in forest assessment and monitoring are included. Many airborne laser scanning missions are being flown with terrain mapping requirements, leading to data sets that are missing important data for vegetation evaluation. As a result, standards and criteria for airborne laser scanning missions are needed to guarantee that they are used for vegetation measurement and monitoring instead of merely landscape mapping (e.g., delivery of all return data with reflection intensity).

Application of the Msplit method for filtering airborne laser scanning data-sets to estimate digital terrain models

2015 ◽  
Vol 36 (9) ◽  
pp. 2421-2437 ◽  
Author(s):  
Wioleta Błaszczak-Bąk ◽  
Artur Janowski ◽  
Waldemar Kamiński ◽  
Jacek Rapiński
Keyword(s):  
Laser Scanning ◽  
Airborne Laser Scanning ◽  
Data Sets ◽  
Digital Terrain Models ◽  
Digital Terrain ◽  
Terrain Models ◽  
Airborne Laser

scholarly journals EcoDes-DK15: High-resolution ecological descriptors of vegetation and terrain derived from Denmark's national airborne laser scanning data set

2021 ◽  
Author(s):  
Jakob J. Assmann ◽  
Jesper E. Moeslund ◽  
Urs A. Treier ◽  
Signe Normand
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Airborne Laser Scanning ◽  
Data Sets ◽  
Ecosystem Structure ◽  
Data Set ◽  
Vegetation Height ◽  
Airborne Laser

Abstract. Biodiversity studies could strongly benefit from three-dimensional data on ecosystem structure derived from contemporary remote sensing technologies, such as Light Detection and Ranging (LiDAR). Despite the increasing availability of such data at regional and national scales, the average ecologist has been limited in accessing them due to high requirements on computing power and remote-sensing knowledge. We processed Denmark's publicly available national Airborne Laser Scanning (ALS) data set acquired in 2014/15 together with the accompanying elevation model to compute 70 rasterized descriptors of interest for ecological studies. With a grain size of 10 m, these data products provide a snapshot of high-resolution measures including vegetation height, structure and density, as well as topographic descriptors including elevation, aspect, slope and wetness across more than forty thousand square kilometres covering almost all of Denmark's terrestrial surface. The resulting data set is comparatively small (~ 87 GB, compressed 16.4 GB) and the raster data can be readily integrated into analytical workflows in software familiar to many ecologists (GIS software, R, Python). Source code and documentation for the processing workflow are openly available via a code repository, allowing for transfer to other ALS data sets, as well as modification or re-calculation of future instances of Denmark’s national ALS data set. We hope that our high-resolution ecological vegetation and terrain descriptors (EcoDes-DK15) will serve as an inspiration for the publication of further such data sets covering other countries and regions and that our rasterized data set will provide a baseline of the ecosystem structure for current and future studies of biodiversity, within Denmark and beyond.

scholarly journals Comparison of field and airborne laser scanning based crown cover estimates across land cover types in Kenya

2015 ◽  
Vol XL-7/W3 ◽  
pp. 409-415 ◽  
Author(s):  
J. Heiskanen ◽  
L. Korhonen ◽  
J. Hietanen ◽  
V. Heikinheimo ◽  
E. Schäfer ◽  
...  
Keyword(s):  
Land Cover ◽  
Laser Scanning ◽  
Field Data ◽  
Forest Cover ◽  
Practical Method ◽  
Airborne Laser Scanning ◽  
Data Sets ◽  
Land Cover Types ◽  
Crown Cover ◽  
Airborne Laser

Tree crown cover (CC) provides means for the continuous land cover characterization of complex tropical landscapes with multiple land uses and variable degrees of degradation. It is also a key parameter in the international forest definitions that are basis for monitoring global forest cover changes. Recently, airborne laser scanning (ALS) has emerged as a practical method for accurate CC mapping, but ALS derived CC estimates have rarely been assessed with field data in the tropics. Here, our objective was to compare the various field and ALS based CC estimates across multiple land cover types in the Taita Hills, Kenya. The field data was measured from a total of 178 sample plots (0.1 ha) in 2013 and 2014. The most accurate field measurement method, line intersect sampling using Cajanus tube, was used in 37 plots. Other methods included CC estimate based on the tree inventory data (144 plots), crown relascope (43 plots) and hemispherical photography (30 plots). Three ALS data sets, including two scanners and flying heights, were acquired concurrently with the field data collection. According to the results, the first echo cover index (FCI) from ALS data had good agreement with the most accurate field based CC estimates (RMSD 7.1% and 2.7% depending on the area and scan). The agreement with other field based methods was considerably worse. Furthermore, we observed that ALS cover indices were robust between the different scans in the overlapping area. In conclusion, our results suggest that ALS provides a reliable method for continuous CC mapping across tropical land cover types although dense shrub layer and tree-like herbaceous plants can cause overestimation of CC.

scholarly journals Inference of topographical characteristics for precision agriculture

Geografie ◽  
2014 ◽  
Vol 119 (2) ◽  
pp. 161-178
Author(s):  
Jitka Kumhálová
Keyword(s):  
Precision Agriculture ◽  
Laser Scanning ◽  
Crop Yields ◽  
Airborne Laser Scanning ◽  
Specific Yield ◽  
Data Sets ◽  
Affecting Factors ◽  
Airborne Laser ◽  
Rtk Gps ◽  
Agricultural Yield

Quantitative knowledge of the factors and interactions affecting agricultural yield is essential for site-specific yield management. Topography of the terrain certainly remains on these yield affecting factors. For this reason, this paper deals with the prospects of modelling topographic features – digital elevation models and slope models for an experimental plot with an area of 11.5 hectares. The basis for the creation of these models is formed by data from various sources (combine yield monitor, RTK-GPS and data from airborne laser scanning). These data sets have been then modified via ArcGIS software in order to most accurately describe the topography of the analysed landscape. The resulting models of topographical characteristics were compared with crop yields during the observed period of 2004–2012, in order to determine which data source is best for the evaluation of the influence topography holds over yield values. Data from airborne laser scanning turned out to be the most suitable dataset for the tasks, because of their sufficient accuracy and frequency.

scholarly journals New Advances in Automated Urban Modelling from Airborne Laser Scanning Data

2011 ◽  
Vol 5 (3) ◽  
pp. 196-208 ◽  
Author(s):  
D. F. Laefer ◽  
T. Hinks ◽  
H. Carr ◽  
L. Truong-Hong
Keyword(s):  
Laser Scanning ◽  
Airborne Laser Scanning ◽  
Airborne Laser ◽  
Urban Modelling

scholarly journals Archaeological Surveying of Subarctic and Arctic Landscapes: Comparing the Performance of Airborne Laser Scanning and Remote Sensing Image Data

2021 ◽  
Vol 13 (4) ◽  
pp. 1917
Author(s):  
Alma Elizabeth Thuestad ◽  
Ole Risbøl ◽  
Jan Ingolf Kleppe ◽  
Stine Barlindhaug ◽  
Elin Rose Myrvoll
Keyword(s):  
Remote Sensing ◽  
Laser Scanning ◽  
Digital Terrain Model ◽  
Image Data ◽  
Remote Sensing Image ◽  
Airborne Laser Scanning ◽  
Aerial Images ◽  
Detection Rates ◽  
Airborne Laser ◽  
Pros And Cons

What can remote sensing contribute to archaeological surveying in subarctic and arctic landscapes? The pros and cons of remote sensing data vary as do areas of utilization and methodological approaches. We assessed the applicability of remote sensing for archaeological surveying of northern landscapes using airborne laser scanning (LiDAR) and satellite and aerial images to map archaeological features as a basis for (a) assessing the pros and cons of the different approaches and (b) assessing the potential detection rate of remote sensing. Interpretation of images and a LiDAR-based bare-earth digital terrain model (DTM) was based on visual analyses aided by processing and visualizing techniques. 368 features were identified in the aerial images, 437 in the satellite images and 1186 in the DTM. LiDAR yielded the better result, especially for hunting pits. Image data proved suitable for dwellings and settlement sites. Feature characteristics proved a key factor for detectability, both in LiDAR and image data. This study has shown that LiDAR and remote sensing image data are highly applicable for archaeological surveying in northern landscapes. It showed that a multi-sensor approach contributes to high detection rates. Our results have improved the inventory of archaeological sites in a non-destructive and minimally invasive manner.

scholarly journals Airborne laser scanning reveals large tree trunks on forest floor

2021 ◽  
Vol 491 ◽  
pp. 119225
Author(s):  
Einari Heinaro ◽  
Topi Tanhuanpää ◽  
Tuomas Yrttimaa ◽  
Markus Holopainen ◽  
Mikko Vastaranta
Keyword(s):  
Forest Floor ◽  
Laser Scanning ◽  
Airborne Laser Scanning ◽  
Large Tree ◽  
Airborne Laser

scholarly journals Estimation of Vegetation-Induced Flow Resistance for Hydraulic Computations Using Airborne Laser Scanning Data

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1864
Author(s):  
Peter Mewis
Keyword(s):  
Laser Scanning ◽  
Flow Resistance ◽  
Laser Scanner ◽  
Airborne Laser Scanning ◽  
Density Parameter ◽  
Vegetation Density ◽  
Airborne Laser Scanner ◽  
Airborne Laser ◽  
Bed Roughness ◽  
Available Information

The effect of vegetation in hydraulic computations can be significant. This effect is important for flood computations. Today, the necessary terrain information for flood computations is obtained by airborne laser scanning techniques. The quality and density of the airborne laser scanning information allows for more extensive use of these data in flow computations. In this paper, known methods are improved and combined into a new simple and objective procedure to estimate the hydraulic resistance of vegetation on the flow in the field. State-of-the-art airborne laser scanner information is explored to estimate the vegetation density. The laser scanning information provides the base for the calculation of the vegetation density parameter ωp using the Beer–Lambert law. In a second step, the vegetation density is employed in a flow model to appropriately account for vegetation resistance. The use of this vegetation parameter is superior to the common method of accounting for the vegetation resistance in the bed resistance parameter for bed roughness. The proposed procedure utilizes newly available information and is demonstrated in an example. The obtained values fit very well with the values obtained in the literature. Moreover, the obtained information is very detailed. In the results, the effect of vegetation is estimated objectively without the assignment of typical values. Moreover, a more structured flow field is computed with the flood around denser vegetation, such as groups of bushes. A further thorough study based on observed flow resistance is needed.

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