Estimation of LAI and Related Metrics using Small-footprint Airborne LiDAR without a Digital Terrain Model(ORAL SESSION,Followup and New Challenge for Coming Generations,The Second International Conference on FORCOM,Abstract Proceedings of FORCOM2011)

The Early Medieval Fossa Carolina is the first hydro-engineering construction that bridges the Central European Watershed. The canal was built in 792/793 AD on order of Charlemagne and should connect the drainage systems of the Rhine-Main catchment and the Danube catchment. In this study, we show for the first time, the integration of Airborne LiDAR (Light Detection and Ranging) and geoarchaeological subsurface datasets with the aim to create a 3D-model of Charlemagne’s summit canal. We used a purged Digital Terrain Model that reflects the pre-modern topography. The geometries of buried canal cross-sections are derived from three archaeological excavations and four high-resolution direct push sensing transects. By means of extensive core data, we interpolate the trench bottom and adjacent edges along the entire canal course. As a result, we are able to create a 3D-model that reflects the maximum construction depth of the Carolingian canal and calculate an excavation volume of approx. 297,000 m3. Additionally, we compute the volume of the present dam remnants by Airborne LiDAR data. Surprisingly, the volume of the dam remnants reveals only 120,000 m3 and is much smaller than the computed Carolingian excavation volume. The difference reflects the erosion and anthropogenic overprint since the 8th century AD.

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Accuracy Assessment of Digital Terrain Model Datasets Sources for Hydrogeomorphological Modelling at Mediterranean Catchments

10.20944/preprints201810.0558.v1 ◽

2018 ◽

Author(s):

Lukas Graf ◽

Mariano Moreno-de las Heras ◽

Maurici Ruiz ◽

Josep Fortesa ◽

Aleix Calsamiglia ◽

...

Keyword(s):

Mean Squared Error ◽

Accuracy Assessment ◽

Digital Terrain Model ◽

Airborne Lidar ◽

Stream Network ◽

Terrain Model ◽

Human Land Use ◽

Aster Gdem ◽

Digital Terrain ◽

Vertical Accuracy

Digital Terrain Models (DTMs) are currently a fundamental source of information in Earth Sciences. However, DTM-based studies can contain remarkable biases if limitations and inaccuracies of these models are disregarded. In this work, four freely available datasets such as SRTM C-SAR DEM, ASTER GDEM V2 and two airborne LiDAR derived DTMs (at 5 and 1 m spatial resolution, respectively) were analysed in a comparative study in three geomorphologically contrasted catchments located in Mediterranean geoecosystems under intensive human land use influence. Vertical accuracy as well as the influence of each dataset characteristics on hydrological and geomorphological modelling applicability were assessed by using classic geometric and morphometric parameters and the more recently proposed index of sediment connectivity. Overall vertical accuracy – expressed as Root Mean Squared Error (RMSE) and Normalized Median Deviation (NMAD) – revealed the highest accuracy in the cases of the 1 m (RMSE = 1.55 m; NMAD = 0.44 m) and 5 m LiDAR DTMs (RMSE = 1.73 m; NMAD = 0.84 m). Vertical accuracy of SRTM was lower (RMSE = 6.98 m; NMAD = 5.27 m) but considerably higher than in the case of ASTER (RMSE = 16.10 m; NMAD = 11.23 m). All datasets were affected by systematic distortions. As a consequence, propagation of these errors caused negative impacts on flow routing, stream network and catchment delineation and, to a lower extent, on the distribution of slope values. These limitations should be carefully considered when applying DTMs for hydrogeomorphological modelling.

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ACCURACY ASSESSMENT OF LIDAR-DERIVED DIGITAL TERRAIN MODEL (DTM) WITH DIFFERENT SLOPE AND CANOPY COVER IN TROPICAL FOREST REGION

ISPRS Annals of Photogrammetry Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsannals-ii-2-w2-183-2015 ◽

2015 ◽

Vol II-2/W2 ◽

pp. 183-189 ◽

Cited By ~ 8

Author(s):

M. R. M. Salleh ◽

Z. Ismail ◽

M. Z. A. Rahman

Keyword(s):

Tropical Forest ◽

Digital Terrain Model ◽

Canopy Cover ◽

Airborne Lidar ◽

Lidar Data ◽

Terrain Model ◽

Digital Terrain ◽

Terrain Slope ◽

Airborne Lidar Data

Airborne Light Detection and Ranging (LiDAR) technology has been widely used recent years especially in generating high accuracy of Digital Terrain Model (DTM). High density and good quality of airborne LiDAR data promises a high quality of DTM. This study focussing on the analysing the error associated with the density of vegetation cover (canopy cover) and terrain slope in a LiDAR derived-DTM value in a tropical forest environment in Bentong, State of Pahang, Malaysia. Airborne LiDAR data were collected can be consider as low density captured by Reigl system mounted on an aircraft. The ground filtering procedure use adaptive triangulation irregular network (ATIN) algorithm technique in producing ground points. Next, the ground control points (GCPs) used in generating the reference DTM and these DTM was used for slope classification and the point clouds belong to non-ground are then used in determining the relative percentage of canopy cover. The results show that terrain slope has high correlation for both study area (0.993 and 0.870) with the RMSE of the LiDAR-derived DTM. This is similar to canopy cover where high value of correlation (0.989 and 0.924) obtained. This indicates that the accuracy of airborne LiDAR-derived DTM is significantly affected by terrain slope and canopy caver of study area.

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Using Airborne Lidar for Detection and Morphologic Analysis of Waterbodies Obscured by the Forest Canopy

Transylvanian Review of Systematical and Ecological Research ◽

10.1515/trser-2015-0044 ◽

2015 ◽

Vol 17 (1) ◽

pp. 1-14

Author(s):

Anamaria Roman ◽

Tudor-Mihai Ursu ◽

Sorina Fărcaş ◽

Vlad-Andrei Lăzărescu ◽

Coriolan Horaţiu Opreanu

Keyword(s):

Forest Canopy ◽

Digital Terrain Model ◽

Archaeological Site ◽

Airborne Lidar ◽

Terrain Model ◽

Digital Terrain ◽

Forested Landscapes ◽

Morphologic Analysis ◽

Small Wetland ◽

Important Progress

Abstract The goal of this study was to map watercourses, watersheds, and small wetland features that are completely obscured by the forest canopy using airborne LiDAR (Light Detection and Ranging) within the archaeological site from Porolissum. This technology was used to generate a bare-earth Digital Terrain Model (DTM) with 0.5 m spatial resolution in order to map small depressions and concavities across 10 km2 of forested landscape. Although further research is needed to determine the ecological, geological, and archaeological significance of the mapped waterbodies, the general methodology represents important progress in the rapid and accurate detection of wetland habitats in forested landscapes.

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Least Squares Compactly Supported Radial Basis Function for Digital Terrain Model Interpolation from Airborne Lidar Point Clouds

Remote Sensing ◽

10.3390/rs10040587 ◽

2018 ◽

Vol 10 (4) ◽

pp. 587 ◽

Cited By ~ 3

Author(s):

Chuanfa Chen ◽

Yanyan Li ◽

Na Zhao ◽

Bin Guo ◽

Naixia Mou

Keyword(s):

Radial Basis Function ◽

Least Squares ◽

Basis Function ◽

Digital Terrain Model ◽

Point Clouds ◽

Airborne Lidar ◽

Compactly Supported ◽

Terrain Model ◽

Digital Terrain ◽

Radial Basis

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L-Band UAVSAR Tomographic Imaging in Dense Forests: Gabon Forests

Remote Sensing ◽

10.3390/rs11050475 ◽

2019 ◽

Vol 11 (5) ◽

pp. 475 ◽

Cited By ~ 2

Author(s):

Ibrahim El Moussawi ◽

Dinh Ho Tong Minh ◽

Nicolas Baghdadi ◽

Chadi Abdallah ◽

Jalal Jomaah ◽

...

Keyword(s):

Tropical Forests ◽

Digital Terrain Model ◽

Coefficient Of Determination ◽

Terrain Model ◽

Digital Terrain ◽

Small Footprint ◽

L Band ◽

Waveform Lidar ◽

Lope National Park ◽

Tomographic Analysis

Developing and enhancing strategies to characterize actual forests structure is a timely challenge, particularly for tropical forests. P-band synthetic aperture radar (SAR) tomography (TomoSAR) has previously been demonstrated as a powerful tool for characterizing the 3-D vertical structure of tropical forests, and its capability and potential to retrieve tropical forest structure has been discussed and assessed. On the other hand, the abilities of L-band TomoSAR are still in the early stages of development. Here, we aim to provide a better understanding of L-band TomoSAR capabilities for retrieving the 3-D structure of tropical forests and estimating the top height in dense forests. We carried out tomographic analysis using L-band UAVSAR data from the AfriSAR campaign conducted over Gabon Lopé Park in February 2016. First, it was found that L-band TomoSAR was able to penetrate into and through the canopy down to the ground, and thus the canopy and ground layers were detected correctly. The resulting TomoSAR vertical profiles were validated with a digital terrain model and canopy height model extracted from small-footprint Lidar (SFL) data. Second, there was a strong correlation between the L-band Capon beam forming profile in HH and HV polarizations with Land Vegetation Ice Sensor (LVIS) Level 1B waveform Lidar over different kinds of forest in Gabon Lopé National Park. Finally, forest top height from the L-band data was estimated and validated with SFL data, resulting in a root mean square error of 3 m and coefficient of determination of 0.92. The results demonstrate that L-band TomoSAR is capable of characterizing 3-D structure of tropical forests.

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Assessing the Performance of ICESat-2/ATLAS Multi-Channel Photon Data for Estimating Ground Topography in Forested Terrain

Remote Sensing ◽

10.3390/rs12132084 ◽

2020 ◽

Vol 12 (13) ◽

pp. 2084

Author(s):

Yanqiu Xing ◽

Jiapeng Huang ◽

Armin Gruen ◽

Lei Qin

Keyword(s):

Mean Squared Error ◽

Photon Counting ◽

Digital Terrain Model ◽

Airborne Lidar ◽

Coefficient Of Determination ◽

Laser Altimeter ◽

Terrain Model ◽

Vegetation Height ◽

Counting Approach ◽

Digital Terrain

As a continuation of Ice, Cloud, and Land Elevation Satellite-1 (ICESat-1), the ICESat-2/Advanced Topographic Laser Altimeter System (ATLAS) employs a micro-pulse multi-beam photon counting approach to produce photon data for measuring global terrain. Few studies have assessed the accuracy of different ATLAS channels in retrieving ground topography in forested terrain. This study aims to assess the accuracy of measuring ground topography in forested terrain using different ATLAS channels and the correlation between laser intensity parameters, laser pointing angle parameters, and elevation error. The accuracy of ground topography measured by the ATLAS footprints is evaluated by comparing the derived Digital Terrain Model (DTM) from the ATL03 (Global Geolocated Photon Data) and ATL08 (Land and Vegetation Height) products with that from the airborne Light Detection And Ranging (LiDAR). Results show that the ATLAS product performed well in the study area at all laser intensities and laser pointing angles, and correlations were found between the ATLAS DTM and airborne LiDAR DTM (coefficient of determination––R2 = 1.00, root mean squared error––RMSE = 0.75 m). Considering different laser intensities, there is a significant correlation between the tx_pulse_energy parameter and elevation error. With different laser pointing angles, there is no significant correlation between the tx_pulse_skew_est, tx_pulse_width_lower, tx_pulse_width_upper parameters and the elevation error.

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