Effect of flying altitude and pulse repetition frequency on laser scanner penetration rate for digital elevation model generation in a tropical forest

Lee, Chung Cheng; Wang, Chi-Kuei

doi:10.1080/15481603.2018.1457131

Cited by 9 publications

(6 citation statements)

References 45 publications

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“…The DTM 2016 had the greatest difference with the reference DTM 2012 (0.79 m), followed by DTM 2005 (0.359 m) and DTM 2018 (0.084 m). Different sensors and acquisition configurations can influence the vertical alignment of ALS (Naesset 2009;Lee and Wang 2018). Each of the data sets used in our assessment was acquired with different instruments and acquisition parameters (Table 2).…”

Section: Vertical Alignment Assessment Of Multi-temporal Alsmentioning

confidence: 99%

Harmonizing multi-temporal airborne laser scanning point clouds to derive periodic annual height increments in temperate mixedwood forests

et al. 2022

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When combining multi-temporal airborne laser scanning (ALS) data sets, forest height growth assessments can be compromised due to variations in ALS acquisitions. Herein, we demonstrate the importance of assessing and harmonizing the vertical alignment of multi-temporal ALS data sets used for height growth calculations. Using four ALS acquisitions (2005–2018) in a temperate mixedwood forest, we developed an ALS data harmonization approach and quantified the impact of the harmonization on derived height periodic annual increment (PAI), comparing the ALS-derived PAI to PAI derived from non-harmonized ALS data sets and field measurements. We found significant differences in PAI derived from harmonized and non-harmonized data, and these differences were greater for shorter growth intervals. Data harmonization resulted in a consistent PAI series that reduced uncertainties associated with the different ALS acquisitions. Although overall there was a strong relationship between field and ALS height measures ( R2 ≥ 0.88), we found a weak relationship between the field- and ALS-derived PAI ( R2 = 0.12). We identified systematic errors in field-based tree height measures in plots with complex crowns, tall trees, and restricted visibility. We demonstrate the need for harmonizing multi-temporal ALS data sets for the generation of PAI and, likewise, highlight the need of carefully scrutinize field-measured heights and associated increments.

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Section: Vertical Alignment Assessment Of Multi-temporal Alsmentioning

confidence: 99%

Harmonizing multi-temporal airborne laser scanning point clouds to derive periodic annual height increments in temperate mixedwood forests

et al. 2022

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“…pulses per second. Some sensor models allow tuning the pulse rate providing higher point density at same relative flight height and speed, but resulting in a lower energy per pulse [17]. Lower energy can diminishing the penetration capabilities of canopies, and is therefore taken into consideration when planning a survey, particularly over vegetation.…”

Section: Lidar Characteristicsmentioning

confidence: 99%

Open software and standards in the realm of laser scanning technology

Pirotti

2019

Open geospatial data, softw. stand.

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This review aims at introducing laser scanning technology and providing an overview of the contribution of open source projects for supporting the utilization and analysis of laser scanning data. Lidar technology is pushing to new frontiers in mapping and surveying topographic data. The open source community has supported this by providing libraries, standards, interfaces, modules all the way to full software. Such open solutions provide scientists and end-users valuable tools to access and work with lidar data, fostering new cutting-edge investigation and improvements of existing methods. The first part of this work provides an introduction on laser scanning principles, with references for further reading. It is followed by sections respectively reporting on open standards and formats for lidar data, tools and finally webbased solutions for accessing lidar data. It is not intended to provide a thorough review of state of the art regarding lidar technology itself, but to provide an overview of the open source toolkits available to the community to access, visualize, edit and process point clouds. A range of open source features for lidar data access and analysis is provided, providing an overview of what can be done with alternatives to commercial end-to-end solutions. Data standards and formats are also discussed, showing what are the challenges for storing and accessing massive point clouds. The desiderata are to provide scientists that have not yet worked with lidar data an overview of how this technology works and what open source tools can be a valid solution for their needs in analysing such data. Researchers that are already involved with lidar data will hopefully get ideas on integrating and improving their workflow through open source solutions.

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“…High-resolution (HR) digital elevation models (DEMs) deciphering the fundamental earth surface processes are in frequent use and obtained from three-dimensional (3D) clouds of laser point measurements, comprising dense sampling rates (e.g., 230 laser return from a 1 m 2 area) [1,2]. Airborne laser scanning (ALS) technology has shown higher horizontal and vertical accuracies in the range of 10-15 cm, deciphering the hidden topography under the forests by penetrating through canopies [3,4]. ALS point clouds-ALS ground points (e.g., bare earth laser returns) in particular-allow the creation of HR-DEMs at a userdefined ground sampling distance (GSD) (e.g., 1 m), enabling earth surface representation at several scales through several HR-DEM variants [5,6].…”

Section: Introductionmentioning

confidence: 99%

Accuracy Comparison on Culvert-Modified Digital Elevation Models of DSMA and BA Methods Using ALS Point Clouds

Fareed

Wang

2021

IJGI

Self Cite

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High-resolution digital elevation models (HR-DEMs) originating from airborne laser scanning (ALS) point clouds must be transformed into Culvert-modified DEMs for hydrological and geomorphological analysis. To produce a culvert-modified DEM, information on the locations of drainage structures (DSs) (e.g., bridges and culverts) is essential. Nevertheless, DS mapping techniques, whether in connection with the development of new methods or an application setting of existing methods, have always been complicated. Consequently, wide area DS data are rare, making it challenging to produce a culvert-modified DEM in a wide area capacity. Alternatively, the breach algorithm (BA) method is a standard procedure to obtain culvert-modified DEMs in the absence of DS data, solving the problem to some extent. This paper addresses this shortcoming using a newly developed drainage structure mapping algorithm (DSMA) for obtaining a culvert-modified DEM for an area of 36 km² in Vermont, USA. Benchmark DS data are used as a standard reference to assess the performance of the DSMA method compared to the BA method. A consistent methodological framework is formulated to obtain a culvert-modified DEM using DS data, mapped using the DSMA and resultant culvert-modified DEM is then compared with BA method respectively. The DSs found from the culvert-modified DEMs were reported as true positive (TP), false positive (FP), and false negative (FN). Based on TP, FP, and FN originating from the culvert-modified DEMs of both methods, the evaluation metrics of the false positive rate (FPR) (i.e., the commission error) and false negative rate (FNR) (i.e., the omission error) were computed. Our evaluation showed that the newly developed DSMA-based DS data resulted in an FPR of 0.05 with federal highway authorities (FHWA) roads and 0.12 with non-FHWA roads. The FNR with FHWA roads was 0.07, and with non-FHWA roads, it was 0.38. The BA method showed an FPR of 0.28 with FHWA roads and 0.62 with non-FHWA roads. Similarly, the FNR for the BA method was 0.32 with FHWA roads and 0.61 with non-FHWA roads. The statistics based on the FPR and FNR showed that the DSMA-based culvert-modified DEM was more accurate compared with the BA method, and the formulated framework for producing culvert-modified DEMs using DSMA-based DS data was robust.

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Effect of flying altitude and pulse repetition frequency on laser scanner penetration rate for digital elevation model generation in a tropical forest

Cited by 9 publications

References 45 publications

Harmonizing multi-temporal airborne laser scanning point clouds to derive periodic annual height increments in temperate mixedwood forests

Harmonizing multi-temporal airborne laser scanning point clouds to derive periodic annual height increments in temperate mixedwood forests

Open software and standards in the realm of laser scanning technology

Accuracy Comparison on Culvert-Modified Digital Elevation Models of DSMA and BA Methods Using ALS Point Clouds

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