UAV Photogrammetry and Ground Surveys as a Mapping Tool for Quickly Monitoring Shoreline and Beach Changes

Abstract

The aim of this work is to evaluate UAV photogrammetric and GNSS techniques to investigate coastal zone morphological changes due to both natural and anthropogenic factors. Monitoring morphological beach change and coastline evolution trends is necessary to plan efficient maintenance work, sand refill and engineering structures to avoid coastal drift. The test area is located on the Northern Adriatic coast, a few kilometres from Ravenna (Italy). Three multi-temporal UAV surveys were performed using UAVs supported by GCPs, and Post Processed Kinematic (PPK) surveys were carried out to produce three-dimensional models to be used for comparison and validation. The statistical method based on Crossover Error Analysis was used to assess the empirical accuracy of the PPK surveys. GNSS surveys were then adopted to evaluate the accuracy of the 2019 photogrammetric DTMs. A multi-temporal analysis was carried out by gathering LiDAR dataset (2013) provided by the “Ministero dell’Ambiente e della Tutela del Territorio e del Mare” (MATTM), 1:5000 Regional Technical Cartography (CTR, 1998; DBTR 2013), and 1:5000 AGEA orthophotos (2008, 2011). The digitization of shoreline position on multi-temporal orthophotos and maps, together with DTM comparison, permitted historical coastal changes to be highlighted.

Extending Multi-Beam Sonar with Structure from Motion Data of Shorelines for Complete Pool Bathymetry of Reservoirs

“…Although shoreline modeling has been discussed in the literature [23,24], there has been no description of the effects of masking water in the images used for alignment. Although water masking is not specifically addressed, it is a normal practice to mask and omit image backgrounds and other areas outside the model when processing images because these image areas often result in the creation of erroneous tie points.…”

“…Their paper implies that LiDAR data from a regional survey were used to model the shoreline areas of the reservoir away from the dam, rather than data from sUAV images. Similar research has been done modeling shorelines using a fixed-wing sUAV to collect data over shallow lake and coastal shorelines [23,24]. A fixed-wing sUAV typically collects nadir photos, which is not optimal for steep shorelines or shorelines with sheer cliffs.…”

“…This is a more cost-effective method for generating topography for small areas compared to traditional aerial photogrammetric methods. Extending these general terrain models, recent studies have demonstrated the use of sUAVs and SfM technology in many environmental resource fields, including the field of water resources [15,[17][18][19][20][21][22][23][24], and other applications [25,26]. The majority of this work revolves around using sUAVs' data collection methods to create accurate three-dimensional (3D) topographic models.…”

Accuracy of 3D Landscape Reconstruction without Ground Control Points Using Different UAS Platforms

“…The recent rapid development of relatively low-cost (<US$25,000) small unmanned aerial systems (UASs) (<25 kg) has resulted in their use in a myriad of disciplines. Applications in precision agriculture [1,2], archeological reconstruction [3,4], forestry [5,6], geomorphology [7][8][9], freshwater and marine systems [10][11][12], environmental monitoring [13,14], animal population studies [15][16][17][18], and recently, traffic accident reconstruction [19,20] are just a few of the fields where UASs have been exploited and continue to grow with enhanced platform capabilities (e.g., real-time analysis) [21], advanced sensors [22][23][24] and diverse software implementations [25,26]. The high accuracy and precision (i.e., cm error) of results obtained for 2D (e.g., orthomosaics) and 3D (e.g., digital surface model-DSM) mapping, based on structure from motion with multiview stereo photogrammetry (SfM-MVS), is transforming most disciplines where studies need to characterize areas Drones 2020, 4, 13 2 of 26 up to~100 hectares [1,27,28].…”

Increasing the Geometrical and Interpretation Quality of Unmanned Aerial Vehicle Photogrammetry Products using Super-Resolution Algorithms

“…User demands are growing both for the quality of the modeling and the final resolution. UAVs are used in many areas where visual spectrum images or multi-spectral images, digital surface models (DSMs), and orthoimagery are derived and encompass the following fields: geodesy [6][7][8][9][10][11][12][13][14][15], agriculture [14,[16][17][18][19], forestry [20][21][22], archaeology and architecture [10,[23][24][25][26][27], environment and technical infrastructure monitoring [6,7,11,[17][18][19]21,[28][29][30][31][32][33], and emergency management and traffic monitoring [34][35][36]. Numerous cases of UAV applications have been realized by the author, during which, some problems have been encountered [37].…”