High-resolution Topography Research Articles

Grounding landscape design in high-resolution laser-scanned topography

Topography in landscape design is understood as the foundation on which the dynamics of climate, soil, vegetation and human impact are negotiated. Surprisingly, topography plays a secondary role in the process of designing modern cities, despite being an ineluctable factor on large spatial and temporal scales of built environments. We argue that topographic representation and conceptualization in urban design has been neglected recently despite possibilities of high-resolution scanning techniques. The resulting shortfall of topographic inclusion in design methods limits the achievement of a coherent relationship between terrain, land cover, building and urban space deemed necessary to support evidence-based design methods. This text presents a design method that draws on topography to compose new landscape forms based on site-specific features. The method merges survey and digital modelling to achieve a selective manipulation of georeferenced point cloud models, which are used to represent the measured physical form of the environment. The topic of topography is discussed by first explaining shortcomings of topographic representation and its inclusion in design development, then by devising a design method that draws from point cloud models to handle the physical form of the environment, and finally by discussing the generative role of topography and the new design possibilities offered by this method.

Integration of SSS-Based Reconstructed Results and Bathymetric Data to Obtain High-Resolution and High-Accuracy Underwater Topography

Integration of SSS-Based Reconstructed Results and Bathymetric Data to Obtain High-Resolution and High-Accuracy Underwater Topography

Fast High-Resolution S-PTHA Along the Western Mediterranean Sea Coastlines. Application to the Bay of Cannes

Probabilistic Tsunami Hazard Assessment (PTHA) is a fundamental framework for producing time-independent forecasts of tsunami hazards at the coast, taking into account local to distant tsunamigenic earthquake sources. If high resolution bathymetry and topography data at the shoreline are available, local tsunami inundation models can be computed to identify the highest risk areas and derive evidence-based evacuation plans to improve community safety. We propose a fast high-resolution Seismic-PTHA approach to estimate the tsunami hazard at a coastal level using the Bay of Cannes as test site. The S-PTHA process is firstly fastened by performing seismic and tsunami hazards separately to allow for quick updates, either from seismic rates by adding new earthquakes, or from tsunami hazard by adding new scenarios of tsunamis. Furthermore, significant tsunamis are selected on the basis of the extrapolation of a tsunami amplitude collected offshore from low-resolution simulations to an a priori amplitude nearshore using Green’s law. This allows a saving in computation time on high-resolution simulations of almost 85%. The S-PTHA performed in the Bay of Cannes exhibits maximum expected tsunami waves that do not exceed 1 m in a 2500-year period, except in some particular places such as the Old Port of Cannes. However, the probability to experience wave heights of 30 cm in this same period exceeds 50% along the main beach of Cannes and these results need to be considered in risk mitigation plans given the high touristic attraction of the area, especially in summer times.

Integrated studies to investigate paleochannel aquifer in Dan Chang District, Suphan Buri Province, Western Thailand

Climate change is currently causing droughts in many parts of Thailand, especially in Dan Chang District, Suphan Buri Province where many areas are outside irrigation coverage and deep groundwater explorations are less successful due to groundwater shortages. Therefore, there is a need to explore other shallow groundwater (i.e. less than 15 m deep) resources to relieve the drought problems in the communities. This work uses integrated studies of remote sensing, geology and geophysics to identify the location of a paleochannel that contains shallow groundwater resources in the Nong Makha Mong Subdistrict, Dan Chang District, Suphan Buri Province. Potential sites were selected using preliminary remote sensing analysis along with field surveys. A high-resolution topography map from aerial photos was generated and 2D resistivity imaging surveys were conducted at the selected sites to delineate the location of the paleochannel. The drilled wells prove the success of the integrated study to identify the shallow groundwater in the paleochannel at a depth of 3 to 15 m with a groundwater yield of 4 m3/h. The sediments from the borehole suggest that a combination of alluvial deposits and fluvial sediments. Due to the relative lower cost of drilling shallow wells, this work could be used as a pilot project for local communities to explore shallow groundwater aquifers in paleochannels in areas that face a severe drought crisis and have very little deep groundwater potential.

Sinuous channels east of Olympus Mons, Mars: Implications for volcanic, hydrological, and tectonic processes

The Late Amazonian volcanic plains east of Olympus Mons contain numerous channels and fossae. Channel formation hypotheses have included volcanic processes, flowing water, or a combination of both. To evaluate these hypotheses, we conducted detailed geomorphological and facies mapping at two sites containing channels and fossae representative of features in the region. Based on our mapping and morphological analyses using high resolution topography and images from HiRISE and CTX data, we classified channels into three types, and fossae into two types. Channel Type 1 and Type 2 are consistent with the morphology of lava channels, however, we found no evidence of channel formation due to thermo-mechanical erosion. Additionally, we calculated the potential for lava to achieve turbulent flow within our two study sites and found it unlikely. Channel Type 3 is consistent with fluvial bedrock erosion, likely sourced from erupted groundwater that entrained regolith into lahar-like flows. Fossae are classified as linear (Type L) or arcuate and branched (Type A). Type L fossae are interpreted to be surface fractures associated with dike emplacement, whereas Type A fossae are interpreted to be surface fractures due to sill emplacement, which may have melted buried ice deposits and generated meltwater floods. Type 1 and Type 2 channels are associated with Type L fossae and fissure-fed effusive eruptions of lava. In contrast, Type 3 channels are co-located with Type A fossae, and are likely due to outbursts of groundwater possibly related to sill emplacement. We attribute the formation and distribution of channels and fossae throughout the plains east of Olympus Mons to be a consequence of the region’s evolving states of stress, which are predominantly influenced by the loading of Olympus Mons.

Speleogenesis in a lens of metamorphosed limestone and ankerite: Ochtiná Aragonite Cave, Slovakia

The Ochtiná Aragonite Cave (Western Carpathians) represents an unique natural phenomenon. It originated under particular lithological and hydrogeological conditions of the Ochtiná Karst in which several isolated lenses of Paleozoic crystalline limestone (marbles), partly metasomatically altered to ankerite, are enclosed by phyllites. Meteoric water seepage through non-carbonate rocks dissolved limestone and caused the oxidation of ankerite to Fe oxyhydroxides. Carbon dioxide produced during ankerite oxidation enhanced limestone dissolution. The maze cave consists of parallel fault-controlled linear passages and chambers interconnected by transverse horizontal passages. Phreatic and epiphreatic solution morphologies resulted from slowly moving or standing water. These include flat ceilings (Laugdecken), facets (planes of repose, Facetten), lateral notches, convection ceiling cupola-shaped depressions, and spongework-like hollows. Flat ceilings were developed in several altitude positions, each of them probably closely below the slightly oscillated water table. Primary phreatic cupola-shaped depressions, truncated by flat ceilings, represent relics of the oldest cavities (pre-Quaternary? to Early Pleistocene). Inward-sloping smooth facets were not developed only in passages with flat ceilings, but also in the passages and halls with a vaulted ceiling. The asymmetrical shape of cusped depressions above the facets were documented in detail by a high-resolution cave topography with terrestrial laser scanning and digital photogrammetry. Middle–Late Pleistocene accumulation phases, identified by magnetostratigraphy of cave sediments and U-series dating of speleothems, are associated with phreatic and later epiphreatic development. The deposition on the bottom bedrock began before 1.8 Ma. The Brunhes/Matuyama boundary (0.773 Ma) and Jaramillo magnetozone (0.990–1.071 Ma) were recorded in the profile in the Oválna chodba Passage. Slow depositional rate (~0.09 cm/kyr) calculated from magnetostratigraphy resulted from slow water movement in confined conditions in marbles completely enclosed by phyllites and no direct relation to the surface. Only occasionally turbid water was loaded in extremely fine-grained infiltration material and autochthonous Fe oxyhydroxides. The depositional rate in Mn-rich layer was much slower (~0.03 cm/kyr). Additional U-series dating confirmed that old aragonite generations (with ages about 500–450 ka and 143–121 ka) were partly corroded by repeated floods during Late Pleistocene humid episodes. Aragonite younger than 13.5 ka is not corroded.

Role of interfaces in organic–inorganic flexible thermoelectrics

The interface is always a critical factor affecting thermoelectric performance in composite systems. However, understanding the electrical and thermal transport behaviors at the interfaces has been a long-standing challenge. Here, we advance this understanding by using spatially resolved current and thermal measurements in single wall carbon nanotubes (CNTs)-Tellurium-poly(3,4-ethylenedioxythiophene): poly(4-styrenesulfonate) (PEDOT:PSS) nanocomposites. Our results indicate that the obtained ultra-low thermal conductivity in such nanocomposites with high CNTs content can be understood by the interface thermal resistance and interface density of the clusters, which is directly confirmed by quantitative mappings of thermal conductivity in the micro-scale interface regions via scanning thermal microscopy. Furthermore, the highly conductive layers can be formed at the interfaces of Te - PEDOT:PSS and CNTs - PEDOT:PSS revealed by high-resolution local conductivity and topography mapping, leading to simultaneous enhancement of electrical conductivity and Seebeck coefficient. Ultimately, a power factor of 224 µW/mK 2 , as well as an ultralow in-plane thermal conductivity of 0.39 W/mK at 410 K, has been achieved by tuning carrier mobility and phonon scattering using multiple polymer-inorganic interfaces. The ZT value reaches up to 0.24 at 410 K and a planar flexible thermoelectric generator exhibits excellent output power of 1.33 μW and highly competitive normalized maximum power density of 0.26 W/m at a temperature difference of 67.8 K These approaches give deep insights to understand the interface role in nanocomposites, and also attests to the great potential of using such organic–inorganic composites in wearable electronics. We design the multiple interfaces co-existence in CNTs-Te-PEDOT:PSS nanocomposite, the electrical and thermal properties remain decoupled and have been optimized greatly due to the different mechanisms of induced highly conductive layers and strong phonon scattering at multiple polymer-inorganic interfaces. The local electric and thermal behaviors at interfaces has also been revealed by straightforward methods. • The electrical conductivity and Seebeck coefficient are decoupled due to the enhanced mobility at multiple interfaces. • Ultralow in-plane thermal conductivity (0.39 W/mK) has been achieved even in sample with 60 wt% CNTs. • Direct investigations on electric and thermal behaviors at the interface regions are carried out via c-AFM and SThM. • The prepared flexible TE module exhibits competitive outpower comparing with other organic-inorganic TE generators.

Angle-based wavefront sensing enabled by the near fields of flat optics

There is a long history of using angle sensors to measure wavefront. The best example is the Shack-Hartmann sensor. Compared to other methods of wavefront sensing, angle-based approach is more broadly used in industrial applications and scientific research. Its wide adoption is attributed to its fully integrated setup, robustness, and fast speed. However, there is a long-standing issue in its low spatial resolution, which is limited by the size of the angle sensor. Here we report a angle-based wavefront sensor to overcome this challenge. It uses ultra-compact angle sensor built from flat optics. It is directly integrated on focal plane array. This wavefront sensor inherits all the benefits of the angle-based method. Moreover, it improves the spatial sampling density by over two orders of magnitude. The drastically improved resolution allows angle-based sensors to be used for quantitative phase imaging, enabling capabilities such as video-frame recording of high-resolution surface topography.

Nonrigid Bookshelf Kinematics of Northeastern Tibet: Constrains from Fault Slip Rates around the Qinghai Lake and Chaka-Gonghe Basins

Abstract The Elashan fault (ELSF) and Qinghainanshan fault (QHNF), two major faults developed around the Qinghai Lake and Chaka-Gonghe basins, are of great importance for investigating the deformation model of the internal northeastern Tibetan Plateau. However, their late Pleistocene slip rates remain poorly constrained. In this study, we combine high-resolution topography acquired from unmanned aerial vehicles (UAV) and geomorphological dating to calculate the slip rates of the two faults. We visited the central ELSF and western QHNF and measured displaced terraces and stream channels. We collected 10Be samples on the surface of terraces to constrain the abandonment ages. The dextral slip rate of the central segment of the Elashan fault is estimated to be 2.6±1.2 mm/yr. The uplift rates since the late Pleistocene of the Elashan and Qinghainanshan faults are 0.4±0.04 mm/yr and 0.2±0.03 mm/yr, respectively. Comparing the geological rates with the newly published global positioning system (GPS) rates, we find that the slip rates of the major strike-slip faults around the Qinghai Lake and Chaka-Gonghe basins are approximately consistent from the late Pleistocene to the present day. The overall NE shortening rates by summing up the geological slip rates on major faults between the East Kunlun and Haiyuan faults are ~3.4 mm/yr, smaller than the geodetic shortening rates (~4.9 to 6.4 mm/yr), indicating that distributed deformation plays an important role in accommodating the regional deformation. By analyzing the geometrical and kinematic characteristics of the major faults surrounding the basins, we suggest that the kinematic deformation of the internal northeastern Tibet is a nonrigid bookshelf model that consists of counterclockwise rotation (~0.8° Myr-1) and distributed thrusting.

Simulated potential wind power sensitivity to the planetary boundary layer parameterizations combined with various topography datasets in the weather research and forecasting model

Wind power simulation was validated to be sensitive to the planetary boundary layer (PBL) parameterization schemes in the Weather Researching and Forecasting (WRF) model. However, the performance of PBL schemes was rarely evaluated under different resolutions of topography. In this study, we present a sensitivity study to figure out how the resolution of the topography database will influence the performance of PBL schemes. It refers not only to the individual impact of the PBL schemes and topography datasets on wind speed prediction but also the combined interactions. Hourly simulated wind speeds are compared with the measurements at different heights, and these differences are statistically analyzed in both stable and unstable surface layers under the flat and complex terrain. The results show that the Yonsei University (YSU) scheme offers consistently good predictions, however, the Mellor-Yamada-Janjic (MYJ) scheme which has poor performance still provides acceptable outcomes under high-resolution topography. The wind speed shows low sensitivity to the PBL schemes and the relevant wind power density is nearly declined by 6% with refined resolution topography datasets over the complex terrain. Accordingly, a precise topography dataset can increase the simulated robustness of potential wind power prediction.

High-resolution topography of the Antarctic Peninsula combining the TanDEM-X DEM and Reference Elevation Model of Antarctica (REMA) mosaic

Abstract. The Antarctic Peninsula (AP) is one of the widely studied polar regions because of its sensitivity to climate change and potential contribution of its glaciers to global sea level rise. Precise digital elevation models (DEMs) at a high spatial resolution are much demanded for investigating the complex glacier system of the AP at fine scales. However, the two most recent circum-Antarctic DEMs, the 12 m TanDEM-X DEM (TDM DEM) from bistatic interferometric synthetic aperture radar (InSAR) data acquired between 2013 and 2014 and the Reference Elevation Model of Antarctica mosaic (REMA mosaic) at an 8 m spatial resolution derived from optical data acquired between 2011 and 2017 have specific individual limitations in this area. The TDM DEM has the advantage of good data consistency and few data voids (approx. 0.85 %), but there exist residual systematic elevation errors such as phase-unwrapping errors in the non-edited DEM version. The REMA mosaic has high absolute vertical accuracy, but on the AP it suffers from extended areas with data voids (approx. 8 %). To generate a consistent, gapless and high-resolution topography product of the AP, we fill the data voids in the TDM DEM with newly processed TDM raw DEM data acquired in austral winters of 2013 and 2014 and detect and correct the residual systematic elevation errors (i.e., elevation biases) in the TDM DEM with the support of the accurately calibrated REMA mosaic. Instead of a pixelwise replacement with REMA mosaic elevations, these provide reference values to correct the TDM elevation biases over entire regions detected through a path propagation algorithm. The procedure is applied iteratively to gradually correct the errors in the TDM DEM from a large to small scale. The proposed method maintains the characteristics of an InSAR-generated DEM and is minimally influenced by temporal or penetration differences between the TDM DEM and REMA mosaic. The performance of the correction is evaluated with laser altimetry data from Operation IceBridge and ICESat-2 missions. The overall root mean square error (RMSE) of the corrected TDM DEM has been reduced from more than 30 m to about 10 m which together with the improved absolute elevation accuracy indicates comparable values to the REMA mosaic. The generated high-resolution DEM depicts the up-to-date topography of the AP in detail and can be widely used for interferometric applications as well as for glaciological studies on individual glaciers or at regional scales.

X-ray diffraction analysis and X-ray topography of high-quality ScAlMgO4 substrates

X-ray diffraction analysis through high-resolution X-ray rocking curve measurement and X-ray topography was performed on Czockralski (CZ) -grown ScAlMgO4 (SAM) substrates. An extremely narrow rocking curve width of 0.002° (7.2 arcsec) was obtained, and the three-dimensional (3D) configuration of dislocations in the interior of the SAM crystal structure was analyzed through 3D section topography. Burgers vectors of dominating dislocations with slip planes of (0001) were determined to be parallel to the a-axis of the SAM crystal, and the dislocations were found to form clusters.

AFM and Fluorescence Microscopy of Single Cells with Simultaneous Mechanical Stimulation via Electrically Stretchable Substrates.

We have developed a novel experimental set-up that simultaneously, (i) applies static and dynamic deformations to adherent cells in culture, (ii) allows the visualization of cells under fluorescence microscopy, and (iii) allows atomic force microscopy nanoindentation measurements of the mechanical properties of the cells. The cell stretcher device relies on a dielectric elastomer film that can be electro-actuated and acts as the cell culture substrate. The shape and position of the electrodes actuating the film can be controlled by design in order to obtain specific deformations across the cell culture chamber. By using optical markers we characterized the strain fields under different electrode configurations and applied potentials. The combined setup, which includes the cell stretcher device, an atomic force microscope, and an inverted optical microscope, can assess in situ and with sub-micron spatial resolution single cell topography and elasticity, as well as ion fluxes, during the application of static deformations. Proof of performance on fibroblasts shows a reproducible increase in the average cell elastic modulus as a response to applied uniaxial stretch of just 4%. Additionally, high resolution topography and elasticity maps on a single fibroblast can be acquired while the cell is deformed, providing evidence of long-term instrumental stability. This study provides a proof-of-concept of a novel platform that allows in situ and real time investigation of single cell mechano-transduction phenomena with sub-cellular spatial resolution.

Dynamics of recent landslides (

Landslides are common features found on steep slopes on Mars and the role of water in their formation is an open question. Our study focuses on three young martian landslides whose mechanism of formation is unknown and knowing their formation mechanism could give us key information on recent martian climate and/or tectonics. They are less than 5 ​km long, and formed during the Late Amazonian Epoch, with an age <20 ​Ma when Mars is thought to have had a hyperarid climate. To better understand the dynamics and formation mechanism of these landslides, we combine two approaches: geomorphic comparison between martian and terrestrial landslides using remote sensing data from the High Resolution Imaging Science Experiment (HiRISE) and the Colour and Stereo Surface Imaging System (CaSSIS), and numerical modelling using a dry granular flow dynamical model. Our geomorphic analysis revealed two contrasting morphologies suggesting differing dynamics and formation mechanisms. Two of the three martian landslides resemble terrestrial rockslides, while the third is more akin to terrestrial mudslides. The numerical modelling, although not fully conclusive, broadly supports our interpretations from the morphological observations. We suggest that the two landslides resembling terrestrial rockslides could have been triggered by shaking by meteorite impact or marsquakes in the absence of water. On the contrary, we suggest liquid water (originating from ground-ice melted by geothermal heat flux) may have been involved in the initiation of the landslide resembling a terrestrial mudslide. Our results show the value of using morphological comparison between martian and terrestrial landslides combined with numerical modelling to inform the hypotheses of landslide-formation on Mars where in situ analysis is not usually possible.

SUITABLE DEM ASSESSMENT STUDY FOR DATA SCARCE CITIES TOWARDS URBAN EXTREME AND NUISANCE FLOOD MAPPING

Abstract. The high-resolution accurate topography data should be used for extreme and nuisance flood inundation modeling and mapping in cities, but not available for many cities, including most developed countries. It is necessary to study and identify an alternate open-source topographic model that satisfies high-resolution topography datasets’ conditions. We analyzed the open-source DEMs visually, elevation histogram statistics, streams and watershed identification, contour statistics, Topographic Wetness Index, and vertical accuracy of other medium-resolution DEMs compared with high-resolution LiDAR data over New York City to determine alternative open-source Digital Elevation Model in the context of urban flood modeling. In high urban sprawl areas, in the context of flood mapping, our findings have shown that the medium resolution DEMs predicted similar to high-resolution DEMs with the same linear errors around RMSE 25–35ft and LE90 30–40ft. Overall, the ALOS AW3D performed better than other open-source DEMs. Even though SRTM predicted well, it inducted smoothness in DEM where more buildings were located. It noted that ALOS PALSAR DEM is not suitable for any urban studies. ASTER DEM has also shown good agreement with LiDAR and observed elevations, but it induced by noise while processing. Finally, it can be suggested that the ALOS AW3D can be used as an alternative source for urban flood modeling which represented footprints of buildings even though it performed average in vertical accuracy.

Effects of Topography on Planted Trees in a Headwater Catchment on the Chinese Loess Plateau

The Chinese Loess Plateau (CLP) is known for its complex topography of hills and gullies, and lots of human land-use management activities have been put into practice to sustain the soil, water and other natural resources. Afforestation has been widely applied on the CLP and it’s important to understand the effects of topography on these planted trees. However, the coarse spatial resolution of remote sensing data makes it insensitive to local topography, and the traditional in-situ measurements would consume vast amounts of time and resources. In this study, a small headwater catchment of the CLP was selected to study the effects of topography on the planted trees. Low altitude unmanned aerial vehicle based light detection and ranging (UAV-based LiDAR) technology was utilized to obtain high-resolution topography and vegetation structure data. Results showed that the middle transition zone (mid-transition, slope &gt; 45°) was an important boundary of topography in the gully area of the CLP. In the forested catchment, the area of the mid-transition zone had the lowest of tree density, canopy coverage and leaf area index due to steep slope gradient. The tall trees ten to twenty meters high were concentrated in the downhill area, which had the highest canopy coverage and leaf area index. Elevation had significant linear relationships with canopy coverage and leaf area index (p &lt; 0.001), which revealed the impact of topography on the forest indexes of the afforestation catchment. We concluded that the high-resolution LiDAR technology facilitated the research of topography and forest interactions in land surface.

Measuring change at Earth’s surface: On-demand vertical and three-dimensional topographic differencing implemented in OpenTopography

AbstractTopographic differencing measures landscape change by comparing multitemporal high-resolution topography data sets. Here, we focused on two types of topographic differencing: (1) Vertical differencing is the subtraction of digital elevation models (DEMs) that span an event of interest. (2) Three-dimensional (3-D) differencing measures surface change by registering point clouds with a rigid deformation. We recently released topographic differencing in OpenTopography where users perform on-demand vertical and 3-D differencing via an online interface. OpenTopography is a U.S. National Science Foundation–funded facility that provides access to topographic data and processing tools. While topographic differencing has been applied in numerous research studies, the lack of standardization, particularly of 3-D differencing, requires the customization of processing for individual data sets and hinders the community’s ability to efficiently perform differencing on the growing archive of topography data. Our paper focuses on streamlined techniques with which to efficiently difference data sets with varying spatial resolution and sensor type (i.e., optical vs. light detection and ranging [lidar]) and over variable landscapes. To optimize on-demand differencing, we considered algorithm choice and displacement resolution. The optimal resolution is controlled by point density, landscape characteristics (e.g., leaf-on vs. leaf-off), and data set quality. We provide processing options derived from metadata that allow users to produce optimal high-quality results, while experienced users can fine tune the parameters to suit their needs. We anticipate that the differencing tool will expand access to this state-of-the-art technology, will be a valuable educational tool, and will serve as a template for differencing the growing number of multitemporal topography data sets.

Drainage network evolution and reconstruction in an open pit kaolin mine at the edge of the Alto Tajo natural Park

Landform instability of the abandoned Nuria kaolin mine, surrounding the Alto Tajo Natural Park in Spain, has caused frequent and severe environmental impacts due to deficient mining practices, environmental mismanagement and closure planning. Geomorphic instability has caused widespread soil erosion and elevated sediment yields with off-site effects. We quantified such land instability, the evolution of the resulting drainage networks and catchments, and ensuing gully processes. High Resolution Topography sources were compared with historic maps and photos. The current mine rehabilitation practices are depicted based on a geomorphic approach that introduces a sustainable drainage system designed to avoid detected risks. Our aim is reconstructing fluvial channels and related hillslopes that mimic their natural counterparts adapted to a rehabilitation of pre-existing gradient terraces. We demonstrate that: i) mining activity produced a 31–58% decrease in the original site drainage network ii) a post-mining active advancing gully is an indicator of drainage network redevelopment advancing toward an upstream pond with flash-flooding risk; iii) a geomorphic designed and constructed fluvial network and proper drainage density adapted to pre-existing gradient-terraces seeks reestablishing stability; and iv) in absence of sufficient funding for rehabilitation, public/private collaboration agreements play an important role to reinstate landscape stability of abandoned or erroneously restored mines.

Accuracy of DSM By Using Unmanned Aerial Vehicles on the Downstream of Welang Riverbank, District of Pasuruan, Jawa Timur

The Digital Surface Model (DSM) is commonly used in studies on flood map modeling. The lack of accurate, high-resolution topography data has hindered flood modeling. The use of the Unmanned Aerial Vehicle (UAV) can help data acquisition with sufficient accuracy. This research aims to provide high-resolution DSM-generated maps by Ground Control Points (GCPs) settings. Improvement of the model's accuracy was pursued by distributing 20 GCPs along the edges of the study area. Agrisoft software was used to generate the DSM. The generated DSM can be used for various planning purposes. The model's accuracy is measured in Root Mean Square Error (RMSE) based on the generated DSM. The RMSE values are 0.488 m for x-coordinates and y-coordinates (horizontal direction) and 0.161 m for z-coordinates (vertical direction).

Integrated, Speckle-Based Displacement Measurement for Lateral Scanning White Light Interferometry.

Lateral scanning white light interferometry (LSWLI) is a promising technique for high-resolution topography measurements on moving surfaces. To achieve resolutions typically associated with white light interferometry, accurate information on the lateral displacement of the measured surface is essential. Since the uncertainty requirement for a respective displacement measurement is currently not known, Monte Carlo simulations of LSWLI measurements are carried out at first to assess the impact of the displacement uncertainty on the topography measurement. The simulation shows that the uncertainty of the displacement measurement has a larger influence on the total height uncertainty than the uncertainty of the displacing motion itself. Secondly, a sufficiently precise displacement measurement by means of digital speckle correlation (DSC) is proposed that is fully integrated into the field of view of the interferometer. In contrast to externally applied displacement measurement systems, the integrated combination of DSC with LSWLI needs no synchronization and calibration, and it is applicable for translatory as well as rotatory scans. To demonstrate the findings, an LSWLI setup with integrated DSC measurements is realized and tested on a rotating cylindrical object with a surface made of a linear encoder strip.