Low-Cost Very High Resolution Intertidal Vegetation Monitoring Enabled by Near- Infrared Kite Aerial Photography

Total Page:16

File Type:pdf, Size:1020Kb

Low-Cost Very High Resolution Intertidal Vegetation Monitoring Enabled by Near- Infrared Kite Aerial Photography CHAPTER 7 LOW-COST VERY HIGH RESOLUTION INTERTIDAL VEGETATION MONITORING ENABLED BY NEAR- INFRARED KITE AERIAL PHOTOGRAPHY Klaas Pauly & Olivier De Clerck Unsubmitted manuscript Chapter 7 ABSTRACT With ecosystem services of intertidal habitats under rising pressure of human disturbance and climate change, monitoring habitat diversity is increasingly required. However, field-based surveys are time and resource- intensive and often do not provide spatially explicit information. While airborne (multi-spectral) photography and LIDAR (Laser Imaging Detecting And Ranging) offer an efficient, very high resolution and high-quality solution, the costs for skilled crew and equipment often preclude their use in remote areas, for small reserves and in developing countries. We present a simple yet robust, low-cost, low-altitude aerial photography solution using a kite and off-the-shelf camera equipment, resulting in photos covering the near-infrared part of the spectrum for vegetation monitoring. Photos can be mosaiced to generate 3D models, orthophotomosaics, vegetation indices and supervised classifications using low-cost computer vision and remote sensing software. We demonstrate the utility of kite aerial photography for intertidal monitoring in a case study in Northern France and discuss strengths and weaknesses of kite aerial photography. 170 Low-cost intertidal monitoring using kite aerial photography INTRODUCTION Rocky intertidal coasts offer important habitats supporting biodiversity by providing food and shelter. However, these habitats have been observed to decline globally over the past decades, affecting the ecosystem services that they provide (Ambrose & Smith, 2004). Links to human disturbances such as collecting, trampling and turning of rocks have emerged, and these effects may be worsened by climate change in the coming decades. Many countries now require monitoring schemes for these vulnerable habitats (Chust et al., 2008). Changes to benthic communities have often been recorded qualitatively using field surveys in the past. However, inconsistent timing, detail and extent of surveys have hampered establishment of a baseline map and quantitative spatially explicit change detections (Alexander, 2008). Advanced technologies such as remote sensing have been shown to lower the cost in monitoring schemes and increase mapping accuracy significantly (Lengyel et al., 2008). However, spatial resolution of spaceborne imagery precludes capturing the typically high intertidal rocky habitat variability. By contrast, aerial color or multispectral photography or airborne LIDAR have been shown to be effective in intertidal mapping efforts (Chust et al., 2008). Unfortunately, since many factors such as weather and remoteness are involved, the elevated costs for an aircraft together with highly trained staff and special camera equipment often rule out regular monitoring campaigns. Recent years have seen the development of low-cost alternatives, such as the use of small unmanned aerial vehicles (UAV; see Laliberte et al. (2010), although the cost for a professional UAV system still amounts to approximately $60,000) or tethered low-altitude balloon (Planer-Friedrich et al., 2007), helikite (Verhoeven et al., 2009) or kite aerial photography using consumer-grade cameras. Additionally, recent advances in computing power and software availability have enabled low- cost processing of consumer-grade photos, including advanced classifications algorithms and image-based 3D reconstruction. From these systems, kites provide arguably the cheapest and most simple yet robust solution. Kite aerial photography (KAP) has been around since 1887 (Archibald, 1897), but was only much later used in mapping and monitoring studies in the coastal (Scoffin, 1982) and the terrestrial 171 Chapter 7 environment. Since, applications have covered archaeology (Dvorak & Dvorak, 1998), geomorphology (Marzolff & Poesen, 2009), agriculture (Oberthur et al., 2007) and vegetation monitoring (Wundram & Löffler, 2008). As several of these applications require patterns in vegetation health to be detected, imaging the near-infrared (NIR) part of the spectrum became essential to discern different vegetation types and stress factors (Lebourgeois et al., 2008). CCD and CMOS sensors found in digital cameras are inherently sensitive to NIR light, and modified cameras (see Verhoeven, 2008); obtained by removal of the internal NIR-blocking filter in front of the sensor, used by manufacturers to simulate human eye color perception) mounted for KAP have been demonstrated to yield information otherwise not achievable with a digital compact camera (Gerard et al., 1997; Siebert et al., 2004). The aim of the present paper is to explore the utility of NIR-enabled KAP as a tool for monitoring intertidal rocky shore habitats in the Wimereux area (northern France), with a focus on seaweed communities. We assess best baseline mapping practices and show the potential for change detection using two imagery series acquired over 1 year. The rationale is to keep the design of the kite, the camera suspension and operation as well as the subsequent image analysis as simple and low-cost as possible, while using the latest technologies. MATERIAL & METHODS STUDY AREA The study area comprises a rocky intertidal stretch running south-north between the coastal towns of Boulogne-sur-Mer and Wimereux (Nord-Pas- de-Calais, France), known as Pointe de la Crêche, located between N50.750 and N50.756. The area is known to have supported extensive and dense intertidal brown algal communities dominated by Fucus spp. which collapsed between 1990 and 2000 (Coppejans, pers. comm.). Since 2000, wave- exposed rocks are either bare (upper zones), dominated by limpet/barnacle communities (Patella/Balanus) or mussel communities (Mytilus; mid-tidal zones) or spionid worm reefs causing heavy siltation on rock platforms (lower zones). Intertidal seaweed communities dominated by dense Fucus, green algal Ulva spp. and red algal Porphyra stands (mid to upper zones) are 172 Low-cost intertidal monitoring using kite aerial photography still found mostly on the edges of rocky platforms and vertical surfaces. Scattered mixed assemblages with mainly red algae can be found in the lower zones. KITE AERIAL PHOTOGRAPHY Kite aerial photographs were acquired on 16 April 2010 and on 7 April 2011. Depending on wind conditions, either a Rokkaku 7' or FlowForm 32' (figure 1a and 1b) were launched to a height between approximately 80m (in 2011) to 160m (in 2010). The camera was mounted on Brooxes Basic Frames tethered to a Picavet suspension system attached to the kite line approximately 20m below the kite (figure 1b). The camera rig was set to look straight down and an intervalometer was programmed on the camera's SD card using Canon Hacker Development Kit (CHDK, freely available at http://chdk.wikia.com) which triggered the camera every 5 seconds. Hence, no external electronic parts or remote control were used on the camera rig and all settings were made prior to the KAP session, enabling the kite pilot to walk around freely for terrain acquisition. In 2010, photos were taken under overcast conditions with an unmodified (true-color) 12MP Canon Powershot SX200 IS set at ISO 200, 5mm (28mm equivalent) focal length and variable shutter speed and aperture. A shutter speed of at least 1/500th is needed to prevent motion blur. In 2011, both a true-color (RGB) and a false-color series were subsequently acquired. The former used the same SX200 camera, while the false-color camera was a full-spectrum modified 10MP Canon Ixus 870 IS with a red-blocking Lee 172 Lagoon Blue film filter fitted to the lens, hence capturing blue, green and NIR light (Hunt & Linden, 2009). Both cameras were set to 5mm focal length, ISO100 (because of intense direct sunlight) and variable shutter speed and aperture in the latter session. Individual image extent and inherent resolution were calculated before the KAP sessions as a guideline. Photo coverage can be calculated based on the relation between focal length (f), acquisition height (H) and sensor width (d), from which the image width (D) can be calculated as d ⋅ H D = (1) f 173 Chapter 7 A B Figure 1: Equipment for kite aerial photography: a Rokkaku 7' framed (A) or FlowForm 32' frameless kite (B), used depending on wind speed and variability. The camera is suspended from the kite line using a Picavet suspension (1), a Picavet cross (2) and two pivoting Brooxes Basic KAP frames (3) The spatial resolution or ground sampling distance (GSD) can be calculated based on pixel size, acquisition height and focal length as H ⋅ D P(d) GSD = (2) f where P(d) is the number of pixels at the long side of the sensor. For a 12MP camera at 140m flying height and a 10MP camera at 60m flying height at minimal focal length of 5mm, this results in expected coverage and resolution of 173m by 130m at 4cm GSD and 74m by 66m at 2cm GSD per photo for a 1/2.3” camera sensor, respectively. GROUND TRUTHING Two days after the first acquisition date and coinciding with the second date, two separate transects measuring 50m by 2m were delineated including all major habitat types covered by the KAP, for which the outlines were drawn 174 Low-cost intertidal monitoring using kite aerial photography together with field identity codes. The drawings were subsequently digitized an overlaid on the image mosaics to provide classification training and test data, as well as to visualize the difference between aerial photography-based and traditional intertidal
Recommended publications
  • Kite Aerial Photography As a Tool for Remote Sensing 06/28/10 06:49:04 June 2010 Volume 48 Number 3 Article Number 3IAW7
    Kite Aerial Photography as a Tool for Remote Sensing 06/28/10 06:49:04 June 2010 Volume 48 Number 3 Article Number 3IAW7 Return to Current Issue Kite Aerial Photography as a Tool for Remote Sensing Jeff Sallee Assistant Professor/Extension Specialist [email protected] Lesley R. Meier 4-H Graduate Assistant [email protected] 4-H Youth Development Oklahoma State University Stillwater, Oklahoma Abstract: As humans, we perform remote sensing nearly all the time. This is because we acquire most of our information about our surroundings through the senses of sight and hearing. Whether viewed by the unenhanced eye or a military satellite, remote sensing is observing objects from a distance. With our current technology, remote sensing has become a part of daily activities. A relatively inexpensive and practical method to have a firsthand experience with collecting remotely sensed data is kite aerial photography (KAP). KAP can be used as a geospatial tool to teach youth and adults about remote sensing. Introduction Remote sensing, as defined by Nicholas Short (2005), is the use of instruments or sensors to "capture" the spectral and spatial relations of objects and materials observable at a distance. This is how Earth's surface and atmosphere are observed, measured, and interpreted from orbit. In simpler terms, remote sensing refers to the recording, observing, and perceiving (sensing) of objects or events in distant (remote) places. It allows us to have a bird's eye view of places and features on Earth. The earliest forms of remote sensing began with the invention of the camera.
    [Show full text]
  • Kite Aerial Photography
    Kite aerial photography A low cost remote sensing tool for ecological research? -Bart Slot- Supervised by: Prof. dr. J.P. Bakker Rijksuniversiteit Groningen Dr. IC. van Duren International Institute for Geo-lnformation Science •TC and Earth Observation I Tableof contents I Table of contents .1 Acknowledgements { 2 Abstract 3 Introduction 4 objective and questions 5 ResearchMain objective 5 Research hypothesis 5 Methods 6 Study area 6 Kite and lines 6 Kite and lines 7 J Camera equipment and remote control unit 8 Camera 8 Camera rig and suspension 8 Remote control 8 Taking the aerial photographs 9 Regulations and legal issues 10 Ground control points 10 Calibration of non-metric digital cameras 11 Erdas Leica photogrammetic suite (8.7) 12 Vegetation survey 12 Image classification 12 Results 13 Camera calibration 13 Ground control points 14 Base map 15 Exterior orientation results 16 Vegetation classification 16 Visual image interpretation! classification 16 Vegetation survey 17 Supervised classification 19 Digital elevation model 23 profiles 25 MiscellaneousHeight 26 Project costs 28 Discussion 29 References 32 Appendix Appendix 1: Air traffic control 34 Appendix 2: Camera Calibration Photomodeler 5 Status Report Tree 35 J Appendix 3: Ground control points 36 Appendix 4: Exterior orientation parameters 37 Appendix 5: Mayonty filter 37 Appendix 6: DEM accuracy report 38 Appendix 7: Modifying digital camera for Near Infrared (NIR) 39 Appendix 8: Spectral response curve 42 I I I I I Acknowledgements This research project couldn't be done without Iris van Duren, Jan Hendriks en I Gerard Reinink. Their support was vital for my project.I would like to thank ITC for providing an inspiring work environment and the opportunity to let me be in that environment.I also would like to thank Ton Klomphaar from state forestry service, who allowed me to do my research in their terrain.
    [Show full text]
  • AARG BOOKLET FINAL Red.Pdf
    Contents Contents Timetable: Wednesday 24 September 06 Kilberry, Co Meath, Ireland; Community Archaeology Above and Below 20 - Kevin Barton and Justin Kenny Timetable: Thursday 25 September 07 Pick your heritage – archaeological work with public data sets - Martin Fera 21 Law Abiding Citizens? - Susan Curran 08 Automated detection of abandoned livestock enclosures in remotely sensed 22 images of the Silvretta Alps - Karsten Lambers & Igor Zingman Geophysical Survey in the Brú na Bóinne WHS - Conor Brady & Kevin Barton 09 ARCTIS – A MATLAB® toolbox for archaeological imaging 24 South Connemara Aerial Survey - Michael Gibbons 10 spectroscopy - Michael Doneus et al. Exploring the hidden depths of Tara’s hinterland: geophysical and 11 Assessing archive stereo-aerial photographs for reconstructing archaeological 25 landscape investigations in the Meath/north Dublin region - Ger Dowling earthworks - Heather Papworth et al. Big Jobs for Big Data? Issues with the management and maintenance 12 An improved approach to the recognition of standing remains - Aude Crozet, 26 of high-volume research data in Irish archaeology - Mick Corcoran Rachel Opitz & Laure Nuninger Flights of Discovery: and why we need more of them in Ireland! - Gill Barrett 13 NMP data in the EngLaID project - Chris Green 28 Pattern and process: aerial archaeology as new landscape 14 Airborne magnetometer and cultural remains – preliminary results from a test and 29 archaeology? - Dimitrij Mlekuz work in progress - Ole Risbøl & Michael Pregesbauer UAV Photogrammetry – the key to a turn in Icelandic burial 15 A workflow for (semi)-automatic extraction of roads and paths in forested areas 30 archaeology? - Gisli Palsson from Airborne Laser Scan data - Williem Vletter From field-work to..
    [Show full text]
  • Aargnews ISSN 1756-753X the Newsletter of the Aerial Archaeology Research Group
    AARGnews ISSN 1756-753X The newsletter of the Aerial Archaeology Research Group Number 38 March 2009 Contents Editorial 2 In the shadow of crisis: Chairman’s Piece 5 AARG 2009 Siena 9 The role of efficiency in aerial archaeological research of Hungary by Zoltán Czajlik 10 GIS-based analysis of aerial photography, soils and landuse by Johanna Dreßler 18 Recording Landscape and Urban Area Modification: an example from Southern Italy by Pierfrancesco Rescio 25 Small but Perfectly Functional – Quadrocopters and Archaeological Recording by Graeme J Collie, Mike Smith, Ian Black 31 Aerial archaeologists’ meeting at Mainz, Germany by Johanna Dreßler 41 Information for contributors 41 Review article. The influence of aerial photography on the artworks of Kate Whiteford by Sarah Horlock 42 Other books of interest? 46 Juris Urtāns. Augšzemes Ezeri: arheoloğija un folklore [Lakes of Augšzemes: archaeology and folklore] Stefano Campana and Salvatore Piro. Seeing the Unseen. Geophysics and Landscape Archaeology Birger Stichelbaut, Jean Bourgeois, Nicholas Saunders and Piet Chielens (eds). Images of Conflict: Military Aerial Photography and Archaeology Peter Halkon. Archaeology and Environment in a Changing East Yorkshire Landscape: The Foulness Valley c. 800 BC to c. AD 400 Cropmarks 49 AARG: general information, membership, addresses, student bursaries 50 AARGnews 38 (March 2009) Editorial 1 The wheel Several years ago I asked John Hampton, one of the founder members of AARG, why he no longer came to the annual meetings. His reply was that he was fed up with hearing people reinventing the wheel. Yes, there is a certain amount of reinvention, and while this may be necessary to provide each generation, and each country, with its own starting platform, I do sometimes wonder whether sometimes we are going round in circles – or spirals if you want the current theoretical equivalent.
    [Show full text]
  • Cameras and Settings for Aerial Surveys in the Geosciences: Optimizing Image Data
    Cameras and settings for aerial surveys in the geosciences: optimizing image data James O’Connor1†, Mike Smith1, Mike R. James2 1 School of Geography and Geology, Kingston University London 2Lancaster Environment Centre, Lancaster University Keywords: UAV, Digital Image, Photography, Remote Sensing Abstract: Aerial image capture has become very common within the geosciences due to the increasing affordability of low payload (<20 kg) Unmanned Aerial Vehicles (UAVs) for consumer markets. Their application to surveying has subsequently led to many studies being undertaken using UAV imagery and derived products as primary data sources. However, image quality and the principles of image capture are seldom given rigorous discussion. In this contribution we firstly revisit the underpinning concepts behind image capture, from which the requirements for acquiring sharp, well exposed and suitable image data are derived. Secondly, the platform, camera, lens and imaging settings relevant to image quality planning are discussed, with worked examples to guide users through the process of considering the factors required for capturing high quality imagery for geoscience investigations. Given a target feature size and ground sample distance based on mission objectives, flight height and velocity should be calculated to ensure motion blur is kept to a minimum. We recommend using a camera with as big a sensor as is permissible for the aerial platform being used (to maximise sensor sensitivity), effective focal lengths of 24 – 35 mm (to minimize errors due to lens distortion) and optimising ISO (to ensure shutter speed is fast enough to minimise motion blur). Finally, we give recommendations for the reporting of results by researchers in order to help improve the confidence in, and reusability of, surveys through: providing open access imagery where possible, presenting example images and excerpts, and detailing appropriate metadata to rigorously describe the image capture process.
    [Show full text]
  • 15 February 2016 Feature Volume 97, Issue 4
    VOL. 97 NO. 4 15 FEB 2016 Earth & Space Science News Can Biofuels Cool Our Climate? Space-Themed Stamps A Volcano’s Hidden Plumbing Author Identifi ers for AGU Journals Still Time to Register Call for Abstracts There is still time to register for the 2016 Ocean Sciences Meeting, 21-26 February. Visit the Ocean Sciences Meeting website for the latest information on speakers and events. osm.agu.org/2016/ Earth & Space Science News Contents 15 FEBRUARY 2016 FEATURE VOLUME 97, ISSUE 4 20 Using Sounds from the Ocean to Measure Winds in the Stratosphere Stratospheric winds deflect acoustic waves from the oceans. With the right data and the math to analyze them, these waves tell us about the weather aloft. NEWS Special Delivery: Post 8 Office to Issue Space- Themed Stamps Letter writers will be able to adorn their envelopes this year with full-disk images of the planets, Pluto, and the full Moon, as well as Star Trek icons. RESEARCH SPOTLIGHT 14 COVER 29 How Biofuels Can Cool Our Climate The Coming Blue Revolution and Strengthen Our Ecosystems Managing water scarcity, one of the most pressing challenges society faces today, Critics of biofuels like ethanol argue that they are an unsustainable will require a novel conceptual framework use of land. But with careful management, next-generation grass- to understand our place in the hydrologic based biofuels can net climate savings and improve their ecosystems. cycle. Earth & Space Science News Eos.org // 1 Contents DEPARTMENTS Editor in Chief Barbara T. Richman: AGU, Washington, D. C., USA; eos_ [email protected] Editors Christina M.
    [Show full text]
  • Applications of Small-Format Aerial Photography in North Dakota James S
    Applications of small-format aerial photography in North Dakota James S. Aber Earth Science Department, Emporia State University, Emporia, KS 66801 ([email protected]) Introduction color-visible or color-infrared formats. A variety of camera Modern earth science investigations typically involve a lenses and filters can be applied to achieve special effects. combination of techniques and data types ranging from satellite The camera rigs are operated by radio control from the ground imagery, to ground observations, to subsurface geophysics. to pan (0-360°), tilt (0-90°), and fire the shutter. Single-camera Within this spectrum of observational levels, airphotos are rigs weigh 20 to 40 ounces. commonly used for viewing, mapping, and interpreting natural and cultural resources displayed at the Earth’s surface. For more than half a century, airphotos have been utilized for surveys of various archaeological, biological, and geological resources. For example, airphotos are indispensable aids in the preparation of maps of surficial geology in North Dakota and elsewhere. Conventional aerial photographs normally are acquired from airplanes flying 10,000 to 20,000 feet above the terrain. The photographs are taken with large-format cameras that use film 9 inches (23 cm) wide. Photo scale ranges from 1:10,000 to 1:40,000 and resolution is typically 1-2 meters. Figure 1. Cartoon showing setup for kite aerial photography. The Pictures are taken vertically in overlapping sequence to camera rig is suspended from the kite line and is operated by radio provide complete coverage of large ground areas. The control from the ground. Not to scale. National Aerial Photography Program (NAPP) of the U.S.
    [Show full text]
  • Aperture, Shutter & ISO for Kite Aerial Photography
    Aperture, Shutter Speed & ISO for Kite Aerial Photography Copyright Al Edgar Al Edgar Nex 5n, Tv mode, 35mm, f4, 1/1250, ISO 500 February 2014 What You Need for Kite Aerial Photography Set your exposure: • Aperture, Shutter Speed and ISO for the conditions and subject Kite and Reel to lift your camera Camera and control mechanism to aim and compose your shot Kite Aerial Photography • Many similarities to Street Photography: o Pre-visualize the shot you want o Quick reflexes to capture the action when it happens o No time to optimise camera settings – just do it! o Semi automated operation with progressive adjustments pre-set • No time to think! • Many distractions: o Video live feed o People asking questions o Misbehaving kite! • Set and remember! • BUT with… …Thousands of dollars at risk… Copyright Al Edgar Copyright Al Edgar Yours or Mine? Time: Early morning, full sun Camera: NEX 5n (1.5x crop factor) Lens: Minolta 45mm f1.7 Aperture set to f4 Mode: Shutter Priority Shutter: 1/4000th of a second ISO: Automatically adjusts to 100 Choose Your Lens to Suit Your Photography - High quality primes with - Maximum aperture f1.4 to excellent corner resolution f2.8 preferred - Shoot wide, crop savagely - Resistance to flare Copyright Al Edgar Other Important Stuff - Shoot Raw files only - Increase shutter speed by setting – 0.7 EV - Sports mode or continuous frames for action - Candle light mode for dusk - In camera noise reduction – customised to suit ISO Camera Settings • Manual or pre-set focus • TV Mode, Shutter Priority preferred ISO •
    [Show full text]
  • Multispectral Unpiloted Aircraft System
    VOLUME 15 • SPRING 2018 ISSN 2373-5783 San Francisco and Los Angeles 2] Figure 1: The 3DR Solo quadcopter with MicaSense RedEdge camera at Knuthson Meadow. Figure 2: Imagery of Knuthson Meadow collected from quadcopter flights and rendered using the Pix4d software suite. Multispectral 2 ....................................................... Director’s Message . Unpiloted Aircraft System 2 .............................. Sonoma> Assessing PES Projects 4 .................................... San Diego> Optimizing Outdoor ultispectral cameras mounted on unpiloted aircraft Campus Wi-Fi Coverage systems (UAS) are playing an increasingly important 6 ........ San Luis Obispo> Detection of Water Stress in Mrole in precision agriculture, and provide great Vineyards Utilizing UAV promise in biogeographical studies and land cover mapping. and Hyperspectral Imagery Use of near-infrared spectral bands and indices such as the 8 Humbolt> Developing a Coastal GIS Normalized Difference Vegetation Index (NDVI) for capturing ........................... Model of Sri Lanka vegetation health has been used since the 1970s in satellite platforms (e.g. Landsat). In recent years, low-cost UAS platforms 9 ..................................................... San Jose> Virtual Visit: and consumer grade (Canon S95) cameras used for digital Developing a 3D Campus Map surface modeling of gullies (Christian & Davis 2016) has also 11 .........San Marcos> Regeneration of Cypriot Native shown promise for mapping vegetation characteristics when Plants following Agricultural Abandonment modified to capture near infrared (NIR) (Christian 2015). SAVE THE DATE Sensors such as the Parrot Sequoia and MicaSense RedEdge are Please join us at the 2018 ESRI International User Conference in San Diego, California, July 9–13. continued on page 10 Sonoma DIRECTOR’S MESSAGE 2018 Advances in Applied Geospatial Research in the CSU In this issue of the CSU Geospatial Review, CSU scientists demonstrate an array of methods that apply advanced geospatial technologies on our campuses and field sites.
    [Show full text]
  • Automated Archiving of Archaeological Aerial Images
    remote sensing Article Automated Archiving of Archaeological Aerial Images Michael Doneus 1,2,*,†, Martin Wieser 3,†, Geert Verhoeven 2,†, Wilfried Karel 3, Martin Fera 1,4 and Norbert Pfeifer 3 1 Department for Prehistoric and Historical Archaeology, University of Vienna, Franz-Klein-Gasse 1, Vienna 1190, Austria; [email protected] 2 LBI for Archaeological Prospection and Virtual Archaeology, Franz-Klein-Gasse 1, Vienna 1190, Austria; [email protected] 3 Department of Geodesy and Geoinformation, Technische Universität Wien, Gusshausstrasse 27-29, Vienna 1040, Austria; [email protected] (M.W.); [email protected] (W.K.); [email protected] (N.P.) 4 Initiative College for Archaeological Prospection, University of Vienna, Franz-Klein-Gasse 1, Vienna 1190, Austria * Correspondence: [email protected]; Tel.: +43-1-4277-40486 † These authors contributed equally to this work. Academic Editors: Kenneth L. Kvamme, Rosa Lasaponara and Prasad S. Thenkabail Received: 8 January 2016; Accepted: 24 February 2016; Published: 5 March 2016 Abstract: The main purpose of any aerial photo archive is to allow quick access to images based on content and location. Therefore, next to a description of technical parameters and depicted content, georeferencing of every image is of vital importance. This can be done either by identifying the main photographed object (georeferencing of the image content) or by mapping the center point and/or the outline of the image footprint. The paper proposes a new image archiving workflow. The new pipeline is based on the parameters that are logged by a commercial, but cost-effective GNSS/IMU solution and processed with in-house-developed software.
    [Show full text]
  • July 4, 2017 Daniele GIORDAN Handling Editor Potential of Kite
    July 4, 2017 Daniele GIORDAN 5 Handling Editor Potential of kite-borne photogrammetry for decimetric and kilometre square 3D mapping: an application for automatic gully detection Special issue The use of remotely piloted aircraft systems (RPAS) in monitoring applications 10 and management of natural hazards Dear Daniele GIORDAN, We have revised our manuscript according to the remarks and 15 suggestions of the two referees. A point-by-point explanation of our responses to the referees' comments can be found below and then a marked-up manuscript version. As some changes to the manuscript were substantial, we list in this letter these main features before the point-by-point answer to the two reviewers. 20 Both reviewers showed a strong interest to the method of gullies detection. For the irst submission we did not plan to develop much this part but remarks from both reviewers made us re-work on this part and improve it. As a result we substantially changed the end of the introduction, considering 25 that the goal of the paper changed. We also answered the remarks of the second reviewer so that our paper more clearly relates to existing works. We also notably changed the method of gully detection, which lead us to fully rewrite the 2.5 (“Gullies detection”) subsection of the Materials and Methods section and to change the results associated. In the results section, the irst 30 manuscript presented a raw (uniltered) map of gullies and the revised manuscript shows now a “inal” map where most artifacts were removed. We used a deterministic criterion : gullies have to be close to the computed hydrological network.
    [Show full text]
  • Manea & Denver
    K I T E A E R I A L P H O T O G R A P H Y Menea Pit Saturday 23th July 2016 Denver Sluice Sunday 24th July 2016 Last printed Sat 16 July 2016 12:23:42 2 C O N T E N T S Introduction 4 Location 5 The Ouse Washes Landscape Partnership 7 Background 8 Manea Pit 11 The Ouse at Denver 12 Aerial photography: privacy and permissions. 13 KAP risk assessment 14 KAP risk assessment by procedure: steps, risk ranking and amelioration 15 KAP Risk definitions 16 E Q U I P M E N T 17 E Q U I P M E N T C H E C K L I S T 21 O W L P K A P Workshop PARTICIPANT QUESTIONNAIRE 22 Manea & Denver RISK assessement.doc Last printed Sat 16 July 2016 12:23:42 3 - Introduction. The Saturday workshop (weather permitting) will take place at Manea a part of the Ouse Fest event on the SM Guy Memorial Field and Manea Pit. See p5. The Sunday workshop (weather permitting) will take place between Denver Complex and Downham Market, See p6 . The objective is to fly kites and capture low elevation aerial photography of the Manea Pit and the Ouse fest event, the River Great Ouse and its landscape context. Operation of kites will be subject to direction, by all means bring a kite if you like but you must be prepared to fly it as directed by the organiser. All equipment will be provided but you are welcome to bring a camera Please note the following: 1.
    [Show full text]