Tides Measurement and Tidal Analysis at Jakarta Bay

Tides observation conducted for these purposes such as real-time depth of water, determination mean sea level and other tidal datums to establish a system of tidal benchmarks and data for production of tide and tidal current predictions. Center for Marine and Coastal Mapping – Geospatial Information System used water level and tides data mainly to correct the water depth measurement to chart datum. This study uses sea level observation data conducted from 20th February 2018 until 4th April 2018 at Marina Batavia, Jakarta. This study found that tidal types at this location is mixed diurnal using formzahl number. Astronomical and shallow water possible constituent were derived from the harmonic analysis. Fourier analysis gives clearly visual interpretation in frequency perspective. Several constituents inseparable because of short duration records.

ENHANCING UAV COASTAL MAPPING USING INFRARED PANSHARPENING

Ecosystems must now cope with climate change such as rising sea levels. These major changes have a direct impact on the coastal fringe. However, in recent years, coastal ecosystems such as saltmarshes have proven their adaptive capacity. Unmanned Aerial Vehicles (UAV) are an inexpensive and easily deployable alternative which offer us the possibility to monitor these geomorphological and ecological systems, have been perfected over the years, making it possible to achieve high or even very high (VH) spectral and spatial resolution. Detection of changes at VH temporal and spatial resolution such as coastline evolution or seasonal monitoring of plant communities is facilitated. The red-green-blue (RGB) camera is the basic equipment of low-cost UAVs. Many studies have demonstrated the interest of infrared sensors for vegetation or water detection. In this original study, a pansharpening method has been developed to generate a red-edge (RE) and near infrared channel based on the VH resolution of RGB. Out of the three different pansharpening algorithms tested, Gram-Schmidt showed correlation (0.61 and 0.63 for RE and NIR channels respectively), followed by nearest neighbor diffusion and finally, principal component spectral pansharpening. The maximum likelihood, support vector machine and convolutional neural network classifiers were used to discriminate the main objects of the study area. The classification results revealed that at the classifier scale the ML outperforms the others with an overall accuracy of 80.75%. At the spectral band scale, the RE obtains the best performances with 80.04% of OA with ML and 78.34% of OA with SVM.

EXPERIENCE IN DETAILED LANDSCAPE MAPPING OF THE BLACK SEA ABRASION COAST AT THE NORTH-WESTERN CAUCASUS

The landscape units of the Black Sea coast of the North-Western Caucasus have complex and dynamic structures. Mapping of such systems is possible only on a large scale, by superimposing remote sensing data on field research materials. The detailed landscape maps of the marine abrasive coasts of this region were produced for the first time. The landscape structure includes identified hierarchic units: stows, substows, narrow stretched belts, and land facies. A substow was selected as the main unit of analysis for the coastal mapping. The landscape unit map exposes the activity of slope processes and the potential danger areas in the coastal zone.

Coastal Mapping Using DJI Phantom 4 RTK in Post-Processing Kinematic Mode

Topographic and geomorphological surveys of coastal areas usually require the aerial mapping of long and narrow sections of littoral. The georeferencing of photogrammetric models is generally based on the signalization and survey of Ground Control Points (GCPs), which are very time-consuming tasks. Direct georeferencing with high camera location accuracy due to on-board multi-frequency GNSS receivers can limit the need for GCPs. Recently, DJI has made available the Phantom 4 Real-Time Kinematic (RTK) (DJI-P4RTK), which combines the versatility and the ease of use of previous DJI Phantom models with the advantages of a multi-frequency on-board GNSS receiver. In this paper, we investigated the accuracy of both photogrammetric models and Digital Terrain Models (DTMs) generated in Agisoft Metashape from two different image datasets (nadiral and oblique) acquired by a DJI-P4RTK. Camera locations were computed with the Post-Processing Kinematic (PPK) of the Receiver Independent Exchange Format (RINEX) file recorded by the aircraft during flight missions. A Continuously Operating Reference Station (CORS) located at a 15 km distance from the site was used for this task. The results highlighted that the oblique dataset produced very similar results, with GCPs (3D RMSE = 0.025 m) and without (3D RMSE = 0.028 m), while the nadiral dataset was affected more by the position and number of the GCPs (3D RMSE from 0.034 to 0.075 m). The introduction of a few oblique images into the nadiral dataset without any GCP improved the vertical accuracy of the model (Up RMSE from 0.052 to 0.025 m) and can represent a solution to speed up the image acquisition of nadiral datasets for PPK with the DJI-P4RTK and no GCPs. Moreover, the results of this research are compared to those obtained in RTK mode for the same datasets. The novelty of this research is the combination of a multitude of aspects regarding the DJI Phantom 4 RTK aircraft and the subsequent data processing strategies for assessing the quality of photogrammetric models, DTMs, and cross-section profiles.

Post-Hurricane Michael damage assessment using ADCIRC storm surge hindcast, image classification, and LiDAR

Wave forcing from hurricanes, nor’easters, and energetic storms can cause erosion of the berm and beach face resulting in increased vulnerability of dunes and coastal infrastructure. LIDAR or other surveying techniques have quantified post-event morphology, but there is a lack of in situ hydrodynamic and morphodynamic measurements during extreme storm events. Two field studies were conducted in March 2018 and April 2019 at Bethany Beach, Delaware, where in situ hydrodynamic and morphodynamic measurements were made during a nor’easter (Nor’easter Riley) and an energetic storm (Easter Eve Storm). An array of sensors to measure water velocity, water depth, water elevation and bed elevation were mounted to scaffold pipes and deployed in a single cross-shore transect. Water velocity was measured using an electro-magnetic current meter while water and bed elevations were measured using an acoustic distance meter along with an algorithm to differentiate between the water and bed during swash processes. GPS profiles of the beach face were measured during every day-time low tide throughout the storm events. Both accretion and erosion were measured at different cross-shore positions and at different times during the storm events. Morphodynamic change along the back-beach was found to be related to berm erosion, suggesting an important morphologic feedback mechanism. Accumulated wave energy and wave energy flux per unit area between Nor’easter Riley and a recent mid-Atlantic hurricane (Hurricane Dorian) were calculated and compared. Coastal Observations: JALBTCX/NCMP emergency-response airborne Lidar coastal mapping & quick response data products for 2016/2017/2018 hurricane impact assessments

JALBTCX/NCMP emergency-response airborne Lidar coastal mapping & quick response data products for 2016/2017/2018 hurricane impact assessments

The Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX) deployed to support regional-scale post-storm damage assessments following Hurricanes Irma (2017), Maria (2017), and Michael (2018) for the Federal Emergency Management Agency (FEMA) and the U.S. Army Corps of Engineers (USACE) following Hurricanes Matthew (2016) and Florence (2018). The JALBTCX has a long history of providing regional coastal surveys after storm impacts in the United States. These high-resolution, regional datasets extend beyond project boundaries, providing critical data to quantify large-scale impacts associated with storm events. These regional datasets directly support missions within the USACE, other federal agencies, academia, and the broader coastal community.