Accuracy and effectiveness of low cost UASs and open source photogrammetric software for foredunes mapping

Gonçalves, Gil; Pérez, Juan Antonio; Duarte, João

doi:10.1080/01431161.2018.1446568

Cited by 45 publications

(33 citation statements)

References 34 publications

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“…Considering these possible technical and methodological differences, D rms values achieved in this study are very much in line with the expected performance of photogrammetric point clouds. In particular, the performance achieved in this study are better or very close to that of Mancini et al [39], Elsner et al [27] and Gonçalves et al [46] who also compared their photogrammetric point clouds with terrestrial or airborne laser scanner measurements. To be noted also is that E rms achieved by Laporte-Fauret et al [44] with 4 GCPs increases up to 0.5 m to 1.12 m (depending on the camera quality) as they compared their photogrammetric DEMs with 5 across-foredune GNSS profiles.…”

Section: Hybrid Uas-mls Performancesupporting

confidence: 86%

“…Similarly, authors using a greater number of GCPs, surveyed with a pole-mounted GNSS receiver, mostly compared GCPs' elevation with the elevation interpolated onto the photogrammetrically-derived DEMs [11,40,41,44]. When both laser (terrestrial or airborne) and photogrammetric data are available, a classic approach is to compare the respectively generated DEMs [27,39,46]. Such comparison implies a densification of the photogrammetric point cloud and, as pointed out by Elsner et al [27], may smooth differences compared to the comparison of raw point clouds.…”

Section: Hybrid Uas-mls Performancementioning

confidence: 99%

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Corridor Mapping of Sandy Coastal Foredunes with UAS Photogrammetry and Mobile Laser Scanning

Nahon

Molina²,

Blázquez³

et al. 2019

Remote Sensing

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Recurrent monitoring of sandy beaches and of the dunes behind them is needed to improve the scientific knowledge on their dynamics as well as to develop sustainable management practices of those valuable landforms. Unmanned Aircraft Systems (UAS) are sought as a means to fulfill this need, especially leveraged by photogrammetric and LiDAR-based mapping methods and technology. The present study compares different strategies to carry UAS photogrammetric corridor mapping over linear extensions of sandy shores. In particular, we present results on the coupling of a UAS with a mobile laser scanning system, operating simultaneously in Cap Ferret, SW France. This aerial-terrestrial tandem enables terrain reconstruction with kinematic ground control points, thus largely avoiding the deployment of surveyed ground control points on the non-stable sandy ground. Results show how these three techniques-mobile laser scanning, photogrammetry based on ground control points, and photogrammetry based on kinematic ground control points-deliver accurate (i.e., root mean square errors < 15 cm) 3D reconstruction of beach-to-dune transition areas, the latter being performed at lower survey and logistic costs, and with enhanced spatial coverage capabilities. This study opens the gate for exploring longer (hundreds of kilometers) shoreline dynamics with ground-control-point-free air and ground mapping techniques.coverage [11]. Indeed, spatial coverage of airborne LiDAR is unmatched [4]. Nonetheless, it involves technological, operational and logistic costs that prevent fast acquisition of pre-and post-storm data for instance. On the other hand, UAS photogrammetric surveys [10,12] are easier to perform, and incorporating post-processed or real-time differential GNSS processing techniques (PPK/RTK) and low-cost, low-to-medium tactical grade Inertial Measurement Units (IMU) implies a reduction in the use of surveyed Ground Control Points (GCPs) [13,14]. However, concerning linear coastal landforms, GCPs remain largely necessary to mitigate accuracy degradation along the corridor, i.e., "bowl effects" [15,16]. This constraint hampers the use of UAS over hundreds of kilometers of shore, as for instance, to survey long sandy beaches after storms [17].Over the last decade, Mobile Laser Scanning (MLS) has emerged as a credible alternative for surveying coastal beaches and foredunes [18][19][20][21]. MLS mainly consist of one or several terrestrial laser scanners mounted on a moving vehicle together with a medium-to-high grade GNSS or IMU/GNSS system. Along the vehicle path, scanners collect 3D point clouds with an accuracy comparable to airborne LiDAR standards at reduced technological and logistic costs. Typical achieved point cloud densities are over 100 points per m 2 , therefore offering a valuable opportunity to study foredune growth with high resolution [20]. Yet, from a coverage standpoint, steep dune slopes create shadow areas and leave large portions of the dune top unscanned. This limitation gives rise to one of the core value proposit...

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Section: Hybrid Uas-mls Performancesupporting

confidence: 86%

Section: Hybrid Uas-mls Performancementioning

confidence: 99%

Corridor Mapping of Sandy Coastal Foredunes with UAS Photogrammetry and Mobile Laser Scanning

Nahon

Molina²,

Blázquez³

et al. 2019

Remote Sensing

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“…The vertical accuracy achieved in this work is also comparable with the results obtained from other similar UAS studies conducted under different geomorphologic settings (Table 4). For example, our results exceed those reported by Long et al [22], Gonçalves et al [24], and Tonkin et al [18] of 17 cm, 12 cm, and 51.7 cm vertical RMSE, respectively, and are similar to those reported by Gonçalves et al [20] of 2.7-4.6 cm vertical RMSE.…”

Section: Spatial Resolution and Vertical Accuracysupporting

confidence: 77%

“…With careful mission plan, flight execution and image processing, we obtained a dense cloud of 690 points/m 2 for the highest reconstruction quality. It is almost the same density as TLS point clouds (i.e., a mean density of 760 points/m 2 [24]), and denser than most of LiDAR point clouds (i.e., a density of 35 points/m 2 [37]). The dense cloud resulted in a 3.8-cm ultrahigh-resolution DSM.…”

Section: Spatial Resolution and Vertical Accuracymentioning

confidence: 91%

“…They are formed when a river switches from a period of slow vertical incision and valley widening to with UASs and SfM-based photogrammetry provides an efficient and low-cost technique to produce topographic data at high spatial resolutions [17][18][19][20][21]. Meanwhile, accuracies of this approach have been extensively evaluated using terrestrial LiDAR, airborne LiDAR or accurately surveyed ground control points as references [18,20,[22][23][24]. These results suggested that this approach can produce DSMs with accuracies ranging from submeter to centimeter level.…”

Section: Introductionmentioning

confidence: 99%

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Mapping of River Terraces with Low-Cost UAS Based Structure-from-Motion Photogrammetry in a Complex Terrain Setting

Lin

Wang

et al. 2019

Remote Sensing

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River terraces are the principal geomorphic features for unraveling tectonics, sea level, and climate conditions during the evolutionary history of a river. The increasing availability of high-resolution topography data generated by low-cost Unmanned Aerial Systems (UAS) and modern photogrammetry offer an opportunity to identify and characterize these features. In this paper, we assessed the capabilities of UAS-based Structure-from-Motion (SfM) photogrammetry, coupled with a river terrace detection algorithm for mapping of river terraces over a 1.9 km2 valley of complex terrain setting, with a focus on the performance of this latest technology over such complex terrains. With the proposed image acquisition approach and SfM photogrammetry, we constructed a 3.8 cm resolution orthomosaic and digital surface model (DSM). The vertical accuracy of DSM was assessed against 196 independent checkpoints measured with a real-time kinematic (RTK) GPS. The results indicated that the root mean square error (RMSE) and mean absolute error (MAE) were 3.1 cm and 2.9 cm, respectively. These encouraging results suggest that this low-cost, logistically simple method can deliver high-quality terrain datasets even in the complex terrain, competitive with those obtained using more expensive laser scanning. A simple algorithm was then employed to detect river terraces from the generated DSM. The results showed that three levels of river terraces and a high-level floodplain were identified. Most of the detected river terraces were confirmed by field observations. Despite the highly erosive nature of fluvial systems, this work obtained good results, allowing fast analysis of fluvial valleys and their comparison. Overall, our results demonstrated that the low-cost UAS-based SfM technique could yield highly accurate ultrahigh-resolution topography data over complex terrain settings, making it particularly suitable for quick and cost-effective mapping of micro to medium-sized geomorphic features under such terrains in remote or poorly accessible areas. Methods discussed in this paper can also be applied to produce highly accurate digital terrain data over large spatial extents for some other places of complex terrains.

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Mapping potential surface ponding in agriculture using UAV‐SfM

Straffelini

Cucchiaro

Tarolli

2021

Earth Surf Processes Landf

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Among the environmental problems that could affect agriculture, one of the most critical is ponding. This may be defined as water storage on the surface in concavities and depressions due to soil saturation. Stagnant water can seriously affect crops and the management of agricultural landscapes. It is mainly caused by prolonged rainfall events, soil type, or wrong mechanization practices, which cause soil compaction. To better understand this problem and thus provide adequate solutions to reduce the related risk, high-resolution topographic information could be strategically important because it offers an accurate representation of the surface morphology. In the last decades, new remote sensing techniques provide interesting opportunities to understand the processes on the Earth's surface based on geomorphic signatures. Among these, Uncrewed Aerial Vehicles (UAVs), combined with the structure-from-motion (SfM) photogrammetry technique, represent a solid, low-cost, rapid, and flexible solution for geomorphological analysis. This study aims to present a new approach to detect the potential areas exposed to water stagnation at the farm scale. The high-resolution digital elevation model (DEM) from UAV-SfM data is used to do this. The potential water depth was calculated in the DEM using the relative elevation attribute algorithm. The detection of more pronounced concavities and convexities allowed an estimation and mapping of the potential ponding conditions. The results were assessed by observations and field measurements and are promising, showing a Cohen's k(X) accuracy of 0.683 for the planimetric extent of the ponding phenomena and a Pearson's r xy coefficient of 0.971 for the estimation of pond water depth. The proposed workflow provides a useful indication to stakeholders for better agricultural management in lowland landscapes.

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Accuracy and effectiveness of low cost UASs and open source photogrammetric software for foredunes mapping

Cited by 45 publications

References 34 publications

Corridor Mapping of Sandy Coastal Foredunes with UAS Photogrammetry and Mobile Laser Scanning

Corridor Mapping of Sandy Coastal Foredunes with UAS Photogrammetry and Mobile Laser Scanning

Mapping of River Terraces with Low-Cost UAS Based Structure-from-Motion Photogrammetry in a Complex Terrain Setting

Mapping potential surface ponding in agriculture using UAV‐SfM

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