Assessment of the Precision of a Smart-Phone Pole Photogrammetry for a Second-Order Cliff Surface Deformation Studies

Abstract

Abstract. Coastal cliff is almost a vertical elongated structure with a wave-cut notch and a landslip. Cliffs are geological formations with an almost unpredictable and unstoppable detachment between constitutes formations. Due to health, safety, environmental, and military restrictions, there are more regulations and restrictions on the use of drones. There are also the issues of portability and high cost for the purchase of hybrid drones and Terrestrial Laser Scanners (TLS). These negate the regular monitoring of the coastal cliff. This research develops a rapid, low-cost, and precise digital photogrammetry methodology for the continuous monitoring of the cliff by using the pole as the platform and a mobile phone as a sensor. The most practical vertical camera angle, image overlaps, survey distance to the cliff, and realistic time range for surveys are all determined from the basic surveying principles. Precise geometrically related point clouds generated are with or without the Global Navigation Satellite Systems (GNSS). The standard deviation for “alignment and surface deviation” at every point on each point cloud is ± 0.05 m in the Northing and ± 0.12 m on the Easting’s for the self-calibrated digital camera and without the use of GNSS control points. With the GNSS controls, the maximum deviation in the XYZ coordinates is ± 5 cm. Change analysis performed identifies areas of cut, fill, and the segment of threats in all point clouds. The photogrammetric technique developed is very cheap, simple, and reliable with minimum labor. The results obtained indicate the applicability of this methodology for second-order cliff Deformation study.

Urban Surface Deformation Management: Assessing Dangerous Subsidence Areas through Regional Surface Deformation, Natural Factors, and Human Activities

“…Three-dimensional laser scanning methods, photogrammetry, conventional geodetic technology, etc. can meet the needs of small-scale monitoring [22][23][24][25]. For large areas, methods such as Global Navigation Satellite System (GNSS) and Synthetic Aperture Radar Interferometry (InSAR) are required [26].…”

Analysis of Low-Cost Uav Photogrammetry Solutions for Beach Modelling and Monitoring Using the Opensource Quantum Gis

“…centimetre or sub-centimetre accuracy) to be able to model and analyse small changes in coastal environments (e.g. beach volumetric change) (Eboigbe, 2021;Eboigbe and Kidner, 2020). The mapping of the Penarth coastline stretches from the south end of the pier towards the northern side capturing the cliff embankments (see Figure 2).…”

“…It is bounded by the Severn Estuary on the north shore and the Cardiff Bay at the far south. Penarth has the second largest coastal global tidal range and is predominately characterized by frequent coastal flooding and erosion (Eboigbe, 2021;Eboigbe and Kidner, 2020). The sea level rise at the Penarth impacts greatly to changes along the coast and causes damage to the sea defences.…”

“…Apart from the high cost of data accurate data, such as LiDAR, aerial images, and other high and very-highresolution images (Eboigbe, 2021;Banks et al, 2017;Casella et al, 2014 andBraga et al, 2013), there is also the challenge with acquiring high-cost proprietary software for data processing and analysing (Awange and Kiema, 2018). Regular beach monitoring should include adaptable methodologies for data capture and analysis in terms of frequency and cost (Eboigbe and Kidner, 2020). A long and short-term beach monitoring infrastructure is possible on the availability of regular coastal processes and evolutions (Chang et al, 2018 andTurner et al, 2016).…”