GEOMORPHOLOGICAL MAPPING WITH TERRESTRIAL LASER SCANNING AND UAV-BASED IMAGING

High-resolution digital elevation models (DEMs) are useful for the detailed mapping of geomorphological features. Nowadays various sensors and platforms are available to collect 3D data. The presented study compares terrestrial laser scanning (TLS) and low-cost unmanned aerial vehicles (UAV)-based imaging in terms of their usability for capturing small-scale surface structures. In October 2014 and June 2015 measurements with both systems were carried out in an episodically water-filled karst depression under pasture farming in the region of Hohenlohe (Southwest Germany). The overall aims were to establish high-resolution DEMs and monitor changes of the relief caused by dissolution and compare the advantages and drawbacks of both systems for such studies. Due to the short time between the campaigns the clear detection of temporal changes was hardly possible. However, the multi-temporal campaigns allowed an extensive investigation of the usability of both sensors under different environmental conditions. In addition to the remote sensing measurements, the coordinates of several positions in the study area were measured with a RTK-DGPS system as independent reference data sets in both campaigns. The TLS- and UAV-derived DEM heights at these positions were validated against the DGPS-derived heights. The accuracy of the TLS-derived values is supported by low mean differences between TLS and DGPS measurements while the UAV-derived models show a weaker performance. In the future years additional simultaneous measurements with both approaches under more similar vegetation conditions are necessary to detect surface movements. Moreover, by investigating the subsurface the interaction of above and below ground processes might be detected.

Download Full-text

GEOMORPHOLOGICAL MAPPING WITH TERRESTRIAL LASER SCANNING AND UAV-BASED IMAGING

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xli-b5-591-2016 ◽

2016 ◽

Vol XLI-B5 ◽

pp. 591-597 ◽

Cited By ~ 2

Author(s):

N. Tilly ◽

D. Kelterbaum ◽

R. Zeese

Keyword(s):

High Resolution ◽

Laser Scanning ◽

Low Cost ◽

Terrestrial Laser Scanning ◽

Small Scale ◽

Data Sets ◽

Geomorphological Mapping ◽

3D Data ◽

Multi Temporal ◽

Mean Differences

Download Full-text

Reconstruction of Axial Tomographic High Resolution Data from Confocal Fluorescence Microscopy: A Method for Improving 3D FISH Images

Analytical Cellular Pathology ◽

10.1155/2000/459351 ◽

2000 ◽

Vol 20 (1) ◽

pp. 7-15 ◽

Cited By ~ 18

Author(s):

R. Heintzmann ◽

G. Kreth ◽

C. Cremer

Keyword(s):

High Resolution ◽

Laser Scanning ◽

Axial Direction ◽

Laser Scanning Microscopy ◽

Three Dimensions ◽

Confocal Laser ◽

Data Sets ◽

Data Set ◽

High Resolution Data ◽

3D Data

Fluorescent confocal laser scanning microscopy allows an improved imaging of microscopic objects in three dimensions. However, the resolution along the axial direction is three times worse than the resolution in lateral directions. A method to overcome this axial limitation is tilting the object under the microscope, in a way that the direction of the optical axis points into different directions relative to the sample. A new technique for a simultaneous reconstruction from a number of such axial tomographic confocal data sets was developed and used for high resolution reconstruction of 3D‐data both from experimental and virtual microscopic data sets. The reconstructed images have a highly improved 3D resolution, which is comparable to the lateral resolution of a single deconvolved data set. Axial tomographic imaging in combination with simultaneous data reconstruction also opens the possibility for a more precise quantification of 3D data. The color images of this publication can be accessed from http://www.esacp.org/acp/2000/20‐1/heintzmann.htm. At this web address an interactive 3D viewer is additionally provided for browsing the 3D data. This java applet displays three orthogonal slices of the data set which are dynamically updated by user mouse clicks or keystrokes.

Download Full-text

Surveying and High-Resolution Topography of the Ochtiná Aragonite Cave Based on TLS and Digital Photogrammetry

Applied Sciences ◽

10.3390/app10134633 ◽

2020 ◽

Vol 10 (13) ◽

pp. 4633 ◽

Cited By ~ 2

Author(s):

Katarína Pukanská ◽

Karol Bartoš ◽

Pavel Bella ◽

Juraj Gašinec ◽

Peter Blistan ◽

...

Keyword(s):

High Resolution ◽

Laser Scanning ◽

Terrestrial Laser Scanning ◽

Small Scale ◽

Digital Photogrammetry ◽

Peripheral Surface ◽

High Resolution Models ◽

Flat Solution ◽

Innovation Platform ◽

Very High

The Ochtiná Aragonite Cave (Slovakia, Central Europe) is a world-famous karst phenomenon of significant geological, geomorphological, and mineralogical values. Its specific origin is determined by particular lithological and hydrogeological conditions of the Ochtiná karst formed in lenses of Paleozoic crystalline limestones, partly metasomatically altered to ankerite and siderite. Although the cave is only 300 m long, it represents a combined labyrinth consisting in parallel tectonically controlled halls and passages, that are largely interconnected through transverse conduits of phreatic and epiphreatic morphology with many medium- and small-scale forms originated in slowly moving or standing water (flat solution ceilings, wall inward-inclined facets, water table notches, convectional cupolas, and spongework-like hollows). The highly dissected and irregular morphologies of the cave were surveyed with terrestrial laser scanning and digital photogrammetry. Both used surveying technologies proved to be suitable for quick and accurate mapping of the complicated cave pattern. While terrestrial laser scanning can provide a rapid survey of larger and more complex areas with results delivered directly in the field, digital photogrammetry is able to generate very high-resolution models with quality photo-texture for mapping of small-scale morphologies. Several data on cave morphometry were generated from terrestrial laser scanning (e.g., the area of cave ground plan, the peripheral surface of underground spaces, and their volume). The new detailed map, sections, and 3D model create an innovation platform for a more detailed study on the morphology and genesis of this unusual cave also for its environmental protection and use in tourism.

Download Full-text

Terrestrial laser scanning for quantifying small-scale vertical movements of the ground surface in Artic permafrost regions

10.5194/esurf-2017-49 ◽

2017 ◽

Cited By ~ 3

Author(s):

Sabrina Marx ◽

Katharina Anders ◽

Sofia Antonova ◽

Inga Beck ◽

Julia Boike ◽

...

Keyword(s):

Laser Scanning ◽

Three Dimensional ◽

Ground Surface ◽

Terrestrial Laser Scanning ◽

Spatial Sampling ◽

Small Scale ◽

Vertical Movements ◽

North East ◽

Multi Temporal ◽

Permafrost Regions

Abstract. Three-dimensional data acquired by terrestrial laser scanning (TLS) provides an accurate representation of Earth's surface, which is commonly used to detect and quantify topographic changes on a small scale. However, in Arctic permafrost regions the tundra vegetation and the micro-topography have significant effects on the surface representation in the captured dataset. The resulting spatial sampling of the ground is never identical between two TLS surveys. Thus, monitoring of heave and subsidence in the context of permafrost processes are challenging. This study evaluates TLS for quantifying small-scale vertical movements in an area located within the continuous permafrost zone, 50 km north-east of Inuvik, Northwest Territories, Canada. We propose a novel filter strategy, which accounts for spatial sampling effects and identifies TLS points suitable for multi-temporal deformation analyses. Further important prerequisites must be met, such as accurate co-registration of the TLS datasets. We found that if the ground surface is captured by more than one TLS scan position, plausible subsidence rates (up to mm-scale) can be derived; compared to e.g. standard raster-based DEM difference maps which contain change rates strongly affected by sampling effects.

Download Full-text

Analysis of Gothic Architectural Details by Spatial Object Reconstruction Techniques

Periodica Polytechnica Civil Engineering ◽

10.3311/ppci.10418 ◽

2017 ◽

Author(s):

Árpád József Somogyi ◽

Krisztina Fehér ◽

Tamás Lovas ◽

Balázs Halmos ◽

Árpád Barsi

Keyword(s):

Remote Sensing ◽

High Resolution ◽

Laser Scanning ◽

Historical Analysis ◽

Terrestrial Laser Scanning ◽

Depth Camera ◽

Technical Parameters ◽

3D Data ◽

End Products ◽

High Resolution Models

The paper focuses on the 3D data acquisition technologiesthat support capturing the geometry of medieval architecturalfragmented stones. High-resolution models of such fragmentsenable the analysis of profile shapes as well as the markinglines and curves left by the instruments of stonemasons, andtherefore, indirectly, identifying connections between severalmaster builders could become possible. Considering therequirements of historical analysis and the fact that the investigatedstones are under monument protection, the authorsdecided to use remote sensing technologies, such as structuredlight scanning, terrestrial laser scanning, depth camera andimage-based reconstruction.The paper evaluates the discussed technologies based on theaccuracy and geometric resolution of the obtained 3D models.Besides technical parameters, time and cost requirements alsohave been investigated. The paper gives an overview on theadvantages and shortcomings of the applied data acquisitiontechnologies and of the provided end-products.

Download Full-text

A low-cost technique to measure bank erosion proces ses along middle-size river reaches

10.5194/esurf-2018-3 ◽

2018 ◽

Author(s):

Gonzalo Duró ◽

Alessandra Crosato ◽

Maarten G. Kleinhans ◽

Wim S. J. Uijttewaal

Keyword(s):

Laser Scanning ◽

Spatial Scales ◽

Low Cost ◽

Bank Erosion ◽

Water Levels ◽

Small Scale ◽

Observation Distance ◽

River Bank ◽

Erosion Processes ◽

Rtk Gps

Abstract. Diverse methods are currently available to measure river bank erosion at broad-ranging temporal and spatial scales. Yet, no technique provides low-cost and high-resolution to survey small-scale bank processes along a river reach. We investigate the capabilities of Structure-from-Motion photogrammetry applied with imagery from an Unmanned Aerial Vehicle (UAV) to describe the evolution of riverbank profiles in middle-size rivers. The bank erosion cycle is used as a reference to assess the applicability of different techniques. We surveyed 1.2 km of a restored bank of the Meuse River eight times within a year, combining different photograph perspectives and overlaps to identify an efficient UAV flight to monitor banks. The accuracy of the Digital Surface Models (DSMs) was evaluated compared with RTK GPS points and an Airborne Laser Scanning (ALS) of the whole reach. An oblique perspective with eight photo overlaps was sufficient to achieve the highest relative precision to observation distance of ~1:1400, with 10 cm error range. A complementary nadiral view increased coverage behind bank toe vegetation. The DSM and ALS had comparable accuracies except on banks, where the latter overestimates elevations. Sequential DSMs captured signatures of the erosion cycle such as mass failures, slump-block deposition, and bank undermining. Although this technique requires low water levels and banks without dense vegetation, it is a low-cost method to survey reach-scale riverbanks in sufficient resolution to quantify bank retreat and identify morphological features of the bank failure and erosion processes.

Download Full-text

On the potential of very high-resolution repeat DEMs in glacial and periglacial environments

The Cryosphere ◽

10.5194/tc-4-53-2010 ◽

2010 ◽

Vol 4 (1) ◽

pp. 53-65 ◽

Cited By ~ 69

Author(s):

J. Abermann ◽

A. Fischer ◽

A. Lambrecht ◽

T. Geist

Keyword(s):

High Resolution ◽

Laser Scanning ◽

Airborne Lidar ◽

Primary Data ◽

Glacier Area ◽

Airborne Laser ◽

Multi Temporal ◽

Rock Glaciers ◽

Data Source ◽

Very High

Abstract. The potential of high-resolution repeat DEMs was investigated for glaciological applications including periglacial features (e.g. rock glaciers). It was shown that glacier boundaries can be delineated using airborne LIDAR-DEMs as a primary data source and that information on debris cover extent could be extracted using multi-temporal DEMs. Problems and limitations are discussed, and accuracies quantified. Absolute deviations of airborne laser scanning (ALS) derived glacier boundaries from ground-truthed ones were below 4 m for 80% of the ground-truthed values. Overall, we estimated an accuracy of +/−1.5% of the glacier area for glaciers larger than 1 km2. The errors in the case of smaller glaciers did not exceed +/−5% of the glacier area. The use of repeat DEMs in order to obtain information on the extent, characteristics and activity of rock glaciers was investigated and discussed based on examples.

Download Full-text

Airborne Laser Scanning and Very High-Resolution Satellite Data for Geomorphological Mapping in Parts of Elbe River Valley, Germany

Geoinformatics in Applied Geomorphology ◽

10.1201/b10964-3 ◽

2011 ◽

pp. 23-37

Author(s):

Siddan Anbazhagan ◽

Marco Trommler ◽

Elmar Csaplovics

Keyword(s):

High Resolution ◽

Satellite Data ◽

Laser Scanning ◽

River Valley ◽

Airborne Laser Scanning ◽

Elbe River ◽

Geomorphological Mapping ◽

Airborne Laser ◽

Very High

Download Full-text

RPAS-SfM 4D mapping of shallow landslides activated in a steep terraced vineyard

10.5194/egusphere-egu21-2368 ◽

2021 ◽

Author(s):

Luca Mauri ◽

Eugenio Straffelini ◽

Sara Cucchiaro ◽

Paolo Tarolli

Keyword(s):

High Resolution ◽

Low Cost ◽

Features Extraction ◽

Shallow Landslides ◽

Agricultural System ◽

Agricultural Systems ◽

The Road ◽

Starting Point ◽

Multi Temporal ◽

Geomorphological Changes

The presence of roads is closely linked with the activation of land degradative phenomena such as landslides. Factors such as ineffective road management and design, local rainfall regimes and specific geomorphological elements actively influence landslides occurrence. In this context, recent developments in digital photogrammetry (e.g. Structure from Motion; SfM) paired with Remotely Piloted Aircraft Systems (RPAS) increase our possibilities to realize low-cost and recurrent topographic surveys. This allows the realization of multi-temporal (hereafter 4D) and high-resolution Digital Elevation Models (DEMs), fundamental to analyse geomorphological features and quantify processes at the fine spatial and temporal resolutions at which they occur. In this research is presented a 4D comparison of geomorphological indicators describing a landslide-prone agricultural system, so as to detect the noticed high-steep slope failures. The possibility to analyse the evolution of landslide geomorphic features in steep agricultural systems through high-resolution and 4D comparison of such indicators is still a challenge to be investigated. In this research, we considered a case study located in the central Italian Alps, where two shallow landslides (L1, L2) were activated below a rural road within a terraced vineyard. The dynamics of the landslides were monitored through the comparison of repeated DEMs (DEM of Difference, i.e. DoD), that reported erosion values of above 20 m3 and 10 m3 for the two landslides zones and deposition values of more than 15 m3 and 9 m3 respectively. The elaboration of Relative Path Impact Index (RPII) highlighted the role played by the road in the alteration of surface water flow directions. Altered water flows were expressed by values between 2&#963; and 4&#963; of RPII close to the collapsed surfaces. The increasing of profile curvature and roughness index described landslides evolution over time. Finally, the multi-temporal comparison of features extraction underlined the geomorphological changes affecting the study area. The computation of the quality index underlined the accuracy of features extraction. This index is expressed in a range between 0 (low accuracy) and 1 (high accuracy) and resulted equal to 0.22 m, regarding the landslide observed during the first RPAS survey (L1-pre); 0.63 m, concerning the same landslide detected during the second RPAS survey (L1-post); 0.69 m for L2. Results prove the usefulness of high-resolution and 4D RPAS-based SfM surveys for the investigation of landslides triggering due to the presence of roads at hillslope scale in agricultural systems. This work could be a useful starting point for further studies of landslide-susceptible zones at a wider scale, to preserve the quality and the productivity of affected agricultural areas.

Download Full-text

Stand-alone low-cost sensor network in the inner city of Munich for modeling urban air pollutants

10.5194/egusphere-egu21-15182 ◽

2021 ◽

Author(s):

Adrian Wenzel ◽

Jia Chen ◽

Florian Dietrich ◽

Sebastian T. Thekkekara ◽

Daniel Zollitsch ◽

...

Keyword(s):

Air Quality ◽

High Resolution ◽

Sensor Network ◽

Air Pollutants ◽

Low Cost ◽

Air Pollutant ◽

Sensor Nodes ◽

Sensor Data ◽

Small Scale ◽

Urban Air

Modeling urban air pollutants is a challenging task not only due to the complicated, small-scale topography but also due to the complex chemical processes within the chemical regime of a city. Nitrogen oxides (NOx), particulate matter (PM) and other tracer gases, e.g. formaldehyde, hold information about which chemical regime is present in a city. As we are going to test and apply chemical models for urban pollution &#8211; especially with respect to spatial and temporally variability &#8211; measurement data with high spatial and temporal resolution are critical.Since governmental monitoring stations of air pollutants such as PM, NOx, ozone (O3) or carbon monoxide (CO) are large and costly, they are usually only sparsely distributed throughout a city. Hence, the official monitoring sites are not sufficient to investigate whether small-scale variability and its integrated effects are captured well by models. Smart networks consisting of small low-cost air pollutant sensors have the ability to provide the required grid density and are therefore the tool of choice when it comes to setting up or validating urban modeling frameworks. Such sensor networks have been established and run by several groups, achieving spatial and temporal high-resolution concentration maps [1, 2].After having conducted a measurement campaign in 2016 to create a high-resolution NO2 concentration map for Munich [3], we are currently setting up a low-cost sensor network to measure NOx, PM, O3 and CO concentrations as well as meteorological parameters [4]. The sensors are stand-alone, so that they do not demand mains supply, which gives us a high flexibility in their deployment. Validating air quality models not only requires dense but also high-accuracy measurements. Therefore, we will calibrate our sensor nodes on a weekly basis using a mobile reference instrument and apply the gathered sensor data to a Machine Learning model of the sensor nodes. This will help minimize the often occurring drawbacks of low-cost sensors such as sensor drift, environmental influences and sensor cross sensitivities.&#160;[1] Bigi, A., Mueller, M., Grange, S. K., Ghermandi, G., and Hueglin, C.: Performance of NO, NO2 low cost sensors and three calibration approaches within a real world application, Atmos. Meas. Tech., 11, 3717&#8211;3735, https://doi.org/10.5194/amt-11-3717-2018, 2018[2] Kim, J., Shusterman, A. A., Lieschke, K. J., Newman, C., and Cohen, R. C.: The BErkeley Atmospheric CO2 Observation Network: field calibration and evaluation of low-cost air quality sensors, Atmos. Meas. Tech., 11, 1937&#8211;1946, https://doi.org/10.5194/amt-11-1937-2018, 2018[3] Zhu, Y., Chen, J., Bi, X., Kuhlmann, G., Chan, K. L., Dietrich, F., Brunner, D., Ye, S., and Wenig, M.: Spatial and temporal representativeness of point measurements for nitrogen dioxide pollution levels in cities, Atmos. Chem. Phys., 20, 13241&#8211;13251, https://doi.org/10.5194/acp-20-13241-2020, 2020[4] Zollitsch, D., Chen, J., Dietrich, F., Voggenreiter, B., Setili, L., and Wenig, M.: Low-Cost Air Quality Sensor Network in Munich, EGU General Assembly 2020, Online, 4&#8211;8 May 2020, EGU2020-19276, https://doi.org/10.5194/egusphere-egu2020-19276, 2020

Download Full-text