Remote Sensing

2659 KiB

Open AccessArticle

The Utilization of Historical Data and Geospatial Technology Advances at the Jornada Experimental Range to Support Western America Ranching Culture

by Albert Rango, Kris Havstad and Rick Estell

Remote Sens. 2011, 3(9), 2089-2109; https://doi.org/10.3390/rs3092089 - 20 Sep 2011

Cited by 12 | Viewed by 8365

Abstract

By the early 1900s, concerns were expressed by ranchers, academicians, and federal scientists that widespread overgrazing and invasion of native grassland by woody shrubs were having severe negative impacts upon normal grazing practices in Western America. Ranchers wanted to reverse these trends and [...] Read more.

By the early 1900s, concerns were expressed by ranchers, academicians, and federal scientists that widespread overgrazing and invasion of native grassland by woody shrubs were having severe negative impacts upon normal grazing practices in Western America. Ranchers wanted to reverse these trends and continue their way of life and were willing to work with scientists to achieve these goals. One response to this desire was establishment of the USDA Jornada Experimental Range (783 km²) in south central New Mexico by a Presidential Executive Order in 1912 for conducting rangeland investigations. This cooperative effort involved experiments to understand principles of proper management and the processes causing the woody shrub invasion as well as to identify treatments to eradicate shrubs. By the late 1940s, it was apparent that combining the historical ground-based data accumulated at Jornada Experimental Range with rapidly expanding post World War II technologies would yield a better understanding of the driving processes in these arid and semiarid ecosystems which could then lead to improved rangeland management practices. One specific technology was the use of aerial photography to interpret landscape resource conditions. The assembly and utilization of long-term historical aerial photography data sets has occurred over the last half century. More recently, Global Positioning System (GPS) techniques have been used in a myriad of scientific endeavors including efforts to accurately locate historical and contemporary treatment plots and to track research animals including livestock and wildlife. As an incredible amount of both spatial and temporal data became available, Geographic Information Systems have been exploited to display various layers of data over the same locations. Subsequent analyses of these data layers have begun to yield new insights. The most recent technological development has been the deployment of Unmanned Aerial Vehicles (UAVs) that afford the opportunity to obtain high (5 cm) resolution data now required for rangeland monitoring. The Jornada team is now a leader in civil UAV applications in the USA. The scientific advances at the Jornada in fields such as remote sensing can be traced to the original Western America ranching culture that established the Jornada in 1912 and which persists as an important influence in shaping research directions today. Full article

(This article belongs to the Special Issue Remote Sensing in Natural and Cultural Heritage)

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1530 KiB

Open AccessArticle

Improved Feature Detection in Fused Intensity-Range Images with Complex SIFT (?SIFT)

by Patrick Erik Bradley and Boris Jutzi

Remote Sens. 2011, 3(9), 2076-2088; https://doi.org/10.3390/rs3092076 - 16 Sep 2011

Cited by 8 | Viewed by 7502

Abstract

The real and imaginary parts are proposed as an alternative to the usual Polar representation of complex-valued images. It is proven that the transformation from Polar to Cartesian representation contributes to decreased mutual information, and hence to greater distinctiveness. The Complex Scale-Invariant Feature [...] Read more.

The real and imaginary parts are proposed as an alternative to the usual Polar representation of complex-valued images. It is proven that the transformation from Polar to Cartesian representation contributes to decreased mutual information, and hence to greater distinctiveness. The Complex Scale-Invariant Feature Transform (?SIFT) detects distinctive features in complex-valued images. An evaluation method for estimating the uniformity of feature distributions in complex-valued images derived from intensity-range images is proposed. In order to experimentally evaluate the proposed methodology on intensity-range images, three different kinds of active sensing systems were used: Range Imaging, Laser Scanning, and Structured Light Projection devices (PMD CamCube 2.0, Z+F IMAGER 5003, Microsoft Kinect). Full article

(This article belongs to the Special Issue Terrestrial Laser Scanning)

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Homologous matched feature points in SLP image: <math display="inline"> <msub> <mi>S</mi> <mi>raw</mi> </msub> </math>, <math display="inline"> <msub> <mi>S</mi> <mi>Polar</mi> </msub> </math>, <math display="inline"> <msub> <mi>S</mi> <mi>Cartesian</mi> </msub> </math> (from left to right). Full article ">

670 KiB

Open AccessArticle

Consequences of Uncertainty in Global-Scale Land Cover Maps for Mapping Ecosystem Functions: An Analysis of Pollination Efficiency

by Catharina J.E. Schulp and Rob Alkemade

Remote Sens. 2011, 3(9), 2057-2075; https://doi.org/10.3390/rs3092057 - 16 Sep 2011

Cited by 46 | Viewed by 10308

Abstract

Mapping ecosystem services (ESs) is an important tool for providing the quantitative information necessary for the optimal use and protection of ecosystems and biodiversity. A common mapping approach is to apply established empirical relationships to ecosystem property maps. Often, ecosystem properties that provide [...] Read more.

Mapping ecosystem services (ESs) is an important tool for providing the quantitative information necessary for the optimal use and protection of ecosystems and biodiversity. A common mapping approach is to apply established empirical relationships to ecosystem property maps. Often, ecosystem properties that provide services to humanity are strongly related to the land use and land cover, where the spatial allocation of the land cover in the landscape is especially important. Land use and land cover maps are, therefore, essential for ES mapping. However, insight into the uncertainties in land cover maps and how these propagate into ES maps is lacking. To analyze the effects of these uncertainties, we mapped pollination efficiency as an example of an ecosystem function, using two continental-scale land cover maps and two global-scale land cover maps. We compared the outputs with maps based on a detailed national-scale map. The ecosystem properties and functions could be mapped using the GLOBCOVER map with a reasonable to good accuracy. In homogeneous landscapes, an even coarser resolution map would suffice. For mapping ESs that depend on the spatial allocation of land cover in the landscape, a classification of satellite images using fractional land cover or mosaic classes is an asset. Full article

(This article belongs to the Special Issue Remote Sensing on Earth Observation and Ecosystem Services)

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314 KiB

Open AccessCommentary

Issues in Establishing Climate Sensitivity in Recent Studies

by Kevin E. Trenberth, John T. Fasullo and John P. Abraham

Remote Sens. 2011, 3(9), 2051-2056; https://doi.org/10.3390/rs3092051 - 16 Sep 2011

Cited by 10 | Viewed by 13752

Abstract

Numerous attempts have been made to constrain climate sensitivity with observations [1-10] (with [6] as LC09, [8] as SB11). While all of these attempts contain various caveats and sources of uncertainty, some efforts have been shown to contain major errors and are demonstrably [...] Read more.

Numerous attempts have been made to constrain climate sensitivity with observations [1-10] (with [6] as LC09, [8] as SB11). While all of these attempts contain various caveats and sources of uncertainty, some efforts have been shown to contain major errors and are demonstrably incorrect. For example, multiple studies [11-13] separately addressed weaknesses in LC09 [6]. The work of Trenberth et al. [13], for instance, demonstrated a basic lack of robustness in the LC09 method that fundamentally undermined their results. Minor changes in that study’s subjective assumptions yielded major changes in its main conclusions. Moreover, Trenberth et al. [13] criticized the interpretation of El Niño-Southern Oscillation (ENSO) as an analogue for exploring the forced response of the climate system. In addition, as many cloud variations on monthly time scales result from internal atmospheric variability, such as the Madden-Julian Oscillation, cloud variability is not a deterministic response to surface temperatures. Nevertheless, many of the problems in LC09 [6] have been perpetuated, and Dessler [10] has pointed out similar issues with two more recent such attempts [7,8]. Here we briefly summarize more generally some of the pitfalls and issues involved in developing observational constraints on climate feedbacks. [...] Full article

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2070 KiB

Open AccessArticle

Impacts of Coastal Inundation Due to Climate Change in a CLUSTER of Urban Coastal Communities in Ghana, West Africa

by Kwasi Appeaning Addo, Lloyd Larbi, Barnabas Amisigo and Patrick Kwabena Ofori-Danson

Remote Sens. 2011, 3(9), 2029-2050; https://doi.org/10.3390/rs3092029 - 7 Sep 2011

Cited by 74 | Viewed by 14690

Abstract

The increasing rates of sea level rise caused by global warming within the 21st century are expected to exacerbate inundation and episodic flooding tide in low-lying coastal environments. This development threatens both human development and natural habitats within such coastal communities. The impact [...] Read more.

The increasing rates of sea level rise caused by global warming within the 21st century are expected to exacerbate inundation and episodic flooding tide in low-lying coastal environments. This development threatens both human development and natural habitats within such coastal communities. The impact of sea level rise will be more pronounced in developing countries where there is limited adaptation capacity. This paper presents a comprehensive assessment of the expected impacts of sea level rise in three communities in the Dansoman coastal area of Accra, Ghana. Future sea level rises were projected based on global scenarios and the Commonwealth Scientific and Industrial Research Organization General Circulation Models—CSIRO_MK2_GS GCM. These were used in the SimCLIM model based on the modified Bruun rule and the simulated results overlaid on near vertical aerial photographs taken in 2005. It emerged that the Dansoman coastline could recede by about 202 m by the year 2100 with baseline from 1970 to 1990. The potential impacts on the socioeconomic and natural systems of the Dansoman coastal area were characterized at the Panbros, Grefi and Gbegbeyise communities. The study revealed that about 84% of the local dwellers is aware of the rising sea level in the coastal area but have poor measures of adapting to the effects of flood disasters. Analysis of the likely impacts of coastal inundation revealed that about 650,000 people, 926 buildings and a total area of about 0.80 km² of land are vulnerable to permanent inundation by the year 2100. The study has shown that there will be significant losses to both life and property by the year 2100 in the Dansoman coastal community in the event of sea level rise. Full article

(This article belongs to the Special Issue Remote Sensing in Coastal Ecosystem)

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580 KiB

Open AccessArticle

Modeling Relationships among 217 Fires Using Remote Sensing of Burn Severity in Southern Pine Forests

by Sparkle L. Malone, Leda N. Kobziar, Christina L. Staudhammer and Amr Abd-Elrahman

Remote Sens. 2011, 3(9), 2005-2028; https://doi.org/10.3390/rs3092005 - 7 Sep 2011

Cited by 25 | Viewed by 8923

Abstract

Pine flatwoods forests in the southeastern US have experienced severe wildfires over the past few decades, often attributed to fuel load build-up. These forest communities are fire dependent and require regular burning for ecosystem maintenance and health. Although prescribed fire has been used [...] Read more.

Pine flatwoods forests in the southeastern US have experienced severe wildfires over the past few decades, often attributed to fuel load build-up. These forest communities are fire dependent and require regular burning for ecosystem maintenance and health. Although prescribed fire has been used to reduce wildfire risk and maintain ecosystem integrity, managers are still working to reintroduce fire to long unburned areas. Common perception holds that reintroduction of fire in long unburned forests will produce severe fire effects, resulting in a reluctance to prescribe fire without first using expensive mechanical fuels reduction techniques. To inform prioritization and timing of future fire use, we apply remote sensing analysis to examine the set of conditions most likely to result in high burn severity effects, in relation to vegetation, years since the previous fire, and historical fire frequency. We analyze Landsat imagery-based differenced Normalized Burn Ratios (dNBR) to model the relationships between previous and future burn severity to better predict areas of potential high severity. Our results show that remote sensing techniques are useful for modeling the relationship between elevated risk of high burn severity and the amount of time between fires, the type of fire (wildfire or prescribed burn), and the historical frequency of fires in pine flatwoods forests. Full article

(This article belongs to the Special Issue Advances in Remote Sensing of Wildland Fires)

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93 KiB

Open AccessEditorial

Taking Responsibility on Publishing the Controversial Paper “On the Misdiagnosis of Surface Temperature Feedbacks from Variations in Earth’s Radiant Energy Balance” by Spencer and Braswell, Remote Sens. 2011, 3(8), 1603-1613

by Wolfgang Wagner

Remote Sens. 2011, 3(9), 2002-2004; https://doi.org/10.3390/rs3092002 - 2 Sep 2011

Cited by 4 | Viewed by 33750

Abstract

Peer-reviewed journals are a pillar of modern science. Their aim is to achieve highest scientific standards by carrying out a rigorous peer review that is, as a minimum requirement, supposed to be able to identify fundamental methodological errors or false claims. Unfortunately, as [...] Read more.

Peer-reviewed journals are a pillar of modern science. Their aim is to achieve highest scientific standards by carrying out a rigorous peer review that is, as a minimum requirement, supposed to be able to identify fundamental methodological errors or false claims. Unfortunately, as many climate researchers and engaged observers of the climate change debate pointed out in various internet discussion fora, the paper by Spencer and Braswell [1] that was recently published in Remote Sensing is most likely problematic in both aspects and should therefore not have been published. After having become aware of the situation, and studying the various pro and contra arguments, I agree with the critics of the paper. Therefore, I would like to take the responsibility for this editorial decision and, as a result, step down as Editor-in-Chief of the journal Remote Sensing. [...] Full article

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Open AccessArticle

Demonstration of Two Portable Scanning LiDAR Systems Flown at Low-Altitude for Investigating Coastal Sea Surface Topography

by Julian Vrbancich, Wolfgang Lieff and Jorg Hacker

Remote Sens. 2011, 3(9), 1983-2001; https://doi.org/10.3390/rs3091983 - 2 Sep 2011

Cited by 18 | Viewed by 7969

Abstract

We demonstrate the efficacy of a commercial portable 2D laser scanner (operating at a wavelength close to 1,000 nm) deployed from a fixed-wing aircraft for measuring the sea surface topography and wave profiles over coastal waters. The LiDAR instrumentation enabled simultaneous measurements of [...] Read more.

We demonstrate the efficacy of a commercial portable 2D laser scanner (operating at a wavelength close to 1,000 nm) deployed from a fixed-wing aircraft for measuring the sea surface topography and wave profiles over coastal waters. The LiDAR instrumentation enabled simultaneous measurements of the 2D laser scanner with two independent inertial navigation units, and also simultaneous measurements with a more advanced 2D laser scanner (operating at a wavelength near 1,500 nm). The latter scanner is used routinely for accurately measuring terrestrial topography and was used as a benchmark in this study. We present examples of sea surface topography and wave profiles based on low altitude surveys (< ~300 m) over coastal waters in the vicinity of Cape de Couedic, Kangaroo Island, South Australia and over the surf zone adjacent to the mouth of the Murray River, South Australia. Relative wave heights in the former survey are shown to be consistent with relative wave heights observed from a waverider buoy located near Cape de Couedic during the LiDAR survey. The sea surface topography of waves in the surf zone was successfully mapped with both laser scanners resolving relative wave height variations and fine structure of the sea surface to within approximately 10 cm. A topographic map of the sea surface referenced to the airborne sensor frame transforms to an accurate altimetry map which may be used with airborne electromagnetic instrumentation to provide an averaged altimetry covering a portion of the larger electromagnetic footprint. This averaged altimetry is deemed to be significantly more reliable as a measurement of altimetry than spot measurements using a nadir-looking laser altimeter and would therefore improve upon the use of airborne electromagnetic methods for bathymetric mapping in surf-zone waters. The aperture range of the scanner does not necessarily determine the swath. We observed that instead, the maximum swath at a given altitude was limited by the angle of incidence of the laser at the water surface. Full article

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Open AccessArticle

ICESat/GLAS Data as a Measurement Tool for Peatland Topography and Peat Swamp Forest Biomass in Kalimantan, Indonesia

by Uwe Ballhorn, Juilson Jubanski and Florian Siegert

Remote Sens. 2011, 3(9), 1957-1982; https://doi.org/10.3390/rs3091957 - 2 Sep 2011

Cited by 46 | Viewed by 12447

Abstract

Indonesian peatlands are one of the largest near-surface pools of terrestrial organic carbon. Persistent logging, drainage and recurrent fires lead to huge emission of carbon each year. Since tropical peatlands are highly inaccessible, few measurements on peat depth and forest biomass are available. [...] Read more.

Indonesian peatlands are one of the largest near-surface pools of terrestrial organic carbon. Persistent logging, drainage and recurrent fires lead to huge emission of carbon each year. Since tropical peatlands are highly inaccessible, few measurements on peat depth and forest biomass are available. We assessed the applicability of quality filtered ICESat/GLAS (a spaceborne LiDAR system) data to measure peatland topography as a proxy for peat volume and to estimate peat swamp forest Above Ground Biomass (AGB) in a thoroughly investigated study site in Central Kalimantan, Indonesia. Mean Shuttle Radar Topography Mission (SRTM) elevation was correlated to the corresponding ICESat/GLAS elevation. The best results were obtained from the waveform centroid (R² = 0.92; n = 4,186). ICESat/GLAS terrain elevation was correlated to three 3D peatland elevation models derived from SRTM data (R² = 0.90; overall difference = ?1.0 m, ±3.2 m; n = 4,045). Based on the correlation of in situ peat swamp forest AGB and airborne LiDAR data (R² = 0.75, n = 36) an ICESat/GLAS AGB prediction model was developed (R² = 0.61, n = 35). These results demonstrate that ICESat/GLAS data can be used to measure peat topography and to collect large numbers of forest biomass samples in remote and highly inaccessible peatland forests. Full article

(This article belongs to the Special Issue Laser Scanning in Forests)

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7277 KiB

Open AccessArticle

A Multi-Resolution Multi-Temporal Technique for Detecting and Mapping Deforestation in the Brazilian Amazon Rainforest

by Egídio Arai, Yosio E. Shimabukuro, Gabriel Pereira and Nandamudi L. Vijaykumar

Remote Sens. 2011, 3(9), 1943-1956; https://doi.org/10.3390/rs3091943 - 1 Sep 2011

Cited by 30 | Viewed by 11255

Abstract

The analysis of rapid environment changes requires orbital sensors with high frequency of data acquisition to minimize cloud interference in the study of dynamic processes such as Amazon tropical deforestation. Moreover, a medium to high spatial resolution data is required due to the [...] Read more.

The analysis of rapid environment changes requires orbital sensors with high frequency of data acquisition to minimize cloud interference in the study of dynamic processes such as Amazon tropical deforestation. Moreover, a medium to high spatial resolution data is required due to the nature and complexity of variables involved in the process. In this paper we describe a multiresolution multitemporal technique to simulate Landsat 7 Enhanced Thematic Mapper Plus (ETM+) image using Terra Moderate Resolution Imaging Spectroradiometer (MODIS). The proposed method preserves the spectral resolution and increases the spatial resolution for mapping Amazon Rainfores deforestation using low computational resources. To evaluate this technique, sample images were acquired in the Amazon rainforest border (MODIS tile H12-V10 and ETM+/Landsat 7 path 227 row 68) for 17 July 2002 and 05 October 2002. The MODIS-based simulated ETM+ and the corresponding original ETM+ images were compared through a linear regression method. Additionally, the bootstrap technique was used to calculate the confidence interval for the model to estimate and to perform a sensibility analysis. Moreover, a Linear Spectral Mixing Model, which is the technique used for deforestation mapping in Program for Deforestation Assessment in the Brazilian Legal Amazonia (PRODES) developed by National Institute for Space Research (INPE), was applied to analyze the differences in deforestation estimates. The results showed high correlations, with values between 0.70 and 0.94 (p < 0.05, student’s t test) for all ETM+ bands, indicating a good assessment between simulated and observed data (p < 0.05, Z-test). Moreover, simulated image showed a good agreement with a reference image, originating commission errors of 1% of total area estimated as deforestation in a sample area test. Furthermore, approximately 6% or 70 km² of deforestation areas were missing in simulated image classification. Therefore, the use of Landsat simulated image provides better deforestation estimation than MODIS alone. Full article

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(a) Study area located in Mato Grosso State, Brazilian Amazon, corresponding to the Path 227/Row 68 of Enhanced Thematic Mapper Plus (ETM+) Landsat 7; and (b) annual deforestation estimates of Mato Grosso. Full article ">Figure 2
Methodological procedure to originate the mask of the contribution of ETM+ pixels to the corresponding MODIS reference date pixel (Step 1), and to originate the image by application of the mask in MODIS target date pixel. Full article ">Figure 3
(a) ETM+ reference date of 17 July, 2002 (3B4G5R); (b) MODIS reference date of 17 July 2002 (1B2G6R); (c) MODIS 05 October, 2002 target date image (1B2G6R); (d) ETM+ image of 05 October, 2002 (3B4G5R); and (e) MODIS-based simulated ETM+ image of 05 October 2002 (3B4G5R). Full article ">Figure 4
Linear Regression and slope distributions using the bootstrap technique developed by [<a href="#B36-remotesensing-03-01943" class="html-bibr">36</a>] for shortwave ETM+/Landsat 7 and MODIS-based simulated ETM+ bands. Full article ">Figure 5
05 October 2002, Isoseg classifications of soil fraction images: (a) ETM+ image; (b) MODIS-based simulated ETM image; (c) MODIS image. Full article ">

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Open AccessArticle

AMARTIS v2: 3D Radiative Transfer Code in the [0.4; 2.5 µm] Spectral Domain Dedicated to Urban Areas

by Colin Thomas, Stéphanie Doz, Xavier Briottet and Sophie Lachérade

Remote Sens. 2011, 3(9), 1914-1942; https://doi.org/10.3390/rs3091914 - 31 Aug 2011

Cited by 14 | Viewed by 7529

Abstract

The availability of new very high spatial resolution sensors has for the past few years allowed a precise description of urban areas, and thus the settlement of specific ground or atmosphere characterization methods. However, in order to develop such techniques, a radiative transfer [...] Read more.

The availability of new very high spatial resolution sensors has for the past few years allowed a precise description of urban areas, and thus the settlement of specific ground or atmosphere characterization methods. However, in order to develop such techniques, a radiative transfer tool dedicated to such an area is necessary. AMARTIS v2 is a new radiative transfer code derived from the radiative transfer code AMARTIS specifically dedicated to urban areas. It allows to simulate airborne and spaceborne multiangular observations of 3D scenes in the [0.4; 2.5µm] domain with the ground’s geometry, urban materials optical properties, atmospheric modeling and sensor characteristics entirely defined by the user. After a general presentation of AMARTIS v2 and a description of the performed calculations, results of radiometric intercomparisons with other radiative transfer codes are presented and the new offered potentials are illustrated with four realistic examples, representative of current issues in urban areas remote sensing. Full article

(This article belongs to the Special Issue Hyperspectral Remote Sensing)

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Open AccessArticle

Evaluating the Correctness of Airborne Laser Scanning Data Heights Using Vehicle-Based RTK and VRS GPS Observations

by Satu Dahlqvist, Petri Rönnholm, Panu Salo and Martin Vermeer

Remote Sens. 2011, 3(9), 1902-1913; https://doi.org/10.3390/rs3091902 - 31 Aug 2011

Cited by 5 | Viewed by 7081

Abstract

In this study, we describe a system in which a GPS receiver mounted on the roof of a car is used to provide reference information to evaluate the elevation accuracy and georeferencing of airborne laser scanning (ALS) point clouds. The concept was evaluated [...] Read more.

In this study, we describe a system in which a GPS receiver mounted on the roof of a car is used to provide reference information to evaluate the elevation accuracy and georeferencing of airborne laser scanning (ALS) point clouds. The concept was evaluated in the Klaukkala test area where a number of roads were traversed to collect real-time kinematic data. Two test cases were evaluated, including one case using the real-time kinematic (RTK) method with a dedicated GPS base station at a known benchmark in the area and another case using the GNSSnet virtual reference station service (VRS). The utility of both GPS methods was confirmed. When all test data were included, the mean difference between ALS data and GPS-based observations was ?2.4 cm for both RTK and VRS GPS cases. The corresponding dispersions were ±4.5 cm and ±5.9 cm, respectively. In addition, our examination did not reveal the presence of any significant rotation between ALS and GPS data. Full article

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Open AccessArticle

LIDAR and SODAR Measurements of Wind Speed and Direction in Upland Terrain for Wind Energy Purposes

by Steven Lang and Eamon McKeogh

Remote Sens. 2011, 3(9), 1871-1901; https://doi.org/10.3390/rs3091871 - 25 Aug 2011

Cited by 99 | Viewed by 21981

Abstract

Detailed knowledge of the wind resource is necessary in the developmental and operational stages of a wind farm site. As wind turbines continue to grow in size, masts for mounting cup anemometers—the accepted standard for resource assessment—have necessarily become much taller, and much [...] Read more.

Detailed knowledge of the wind resource is necessary in the developmental and operational stages of a wind farm site. As wind turbines continue to grow in size, masts for mounting cup anemometers—the accepted standard for resource assessment—have necessarily become much taller, and much more expensive. This limitation has driven the commercialization of two remote sensing (RS) tools for the wind energy industry: The LIDAR and the SODAR, Doppler effect instruments using light and sound, respectively. They are ground-based and can work over hundreds of meters, sufficient for the tallest turbines in, or planned for, production. This study compares wind measurements from two commercial RS instruments against an instrumented mast, in upland (semi-complex) terrain typical of where many wind farms are now being installed worldwide. With appropriate filtering, regression analyses suggest a good correlation between the RS instruments and mast instruments: The RS instruments generally recorded lower wind speeds than the cup anemometers, with the LIDAR more accurate and the SODAR more precise. Full article

(This article belongs to the Special Issue Remote Sensing for Sustainable Energy Systems)

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2049 KiB

Open AccessArticle

Mapping Infrared Data on Terrestrial Laser Scanning 3D Models of Buildings

by Mario Ivan Alba, Luigi Barazzetti, Marco Scaioni, Elisabetta Rosina and Mattia Previtali

Remote Sens. 2011, 3(9), 1847-1870; https://doi.org/10.3390/rs3091847 - 25 Aug 2011

Cited by 89 | Viewed by 15244

Abstract

A new 3D acquisition and processing procedure to map RGB, thermal IR and near infrared images (NIR) on a detailed 3D model of a building is presented. The combination and fusion of different data sources allows the generation of 3D thermal data useful [...] Read more.

A new 3D acquisition and processing procedure to map RGB, thermal IR and near infrared images (NIR) on a detailed 3D model of a building is presented. The combination and fusion of different data sources allows the generation of 3D thermal data useful for different purposes such as localization, visualization, and analysis of anomalies in contemporary architecture. The classic approach, which is currently used to map IR images on 3D models, is based on the direct registration of each single image by using space resection or homography. This approach is largely time consuming and in many cases suffers from poor object texture. To overcome these drawbacks, a “bi-camera” system coupling a thermal IR camera to a RGB camera has been setup. The second sensor is used to orient the “bi-camera” through a photogrammetric network also including free-handled camera stations to strengthen the block geometry. In many cases the bundle adjustment can be executed through a procedure for automatic extraction of tie points. Terrestrial laser scanning is adopted to retrieve the 3D model building. The integration of a low-cost NIR camera accumulates further radiometric information on the final 3D model. The use of such a sensor has not been exploited until now to assess the conservation state of buildings. Here some interesting findings from this kind of analysis are reported. The paper shows the methodology and its experimental application to a couple of buildings in the main Campus of Politecnico di Milano University, where IR thermography has previously been carried out for conservation and maintenance purposes. Full article

(This article belongs to the Special Issue Terrestrial Laser Scanning)

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321 KiB

Open AccessReview

Can the Future EnMAP Mission Contribute to Urban Applications? A Literature Survey

by Wieke Heldens, Uta Heiden, Thomas Esch, Enrico Stein and Andreas Müller

Remote Sens. 2011, 3(9), 1817-1846; https://doi.org/10.3390/rs3091817 - 25 Aug 2011

Cited by 53 | Viewed by 9569

Abstract

With urban populations and their footprints growing globally, the need to assess the dynamics of the urban environment increases. Remote sensing is one approach that can analyze these developments quantitatively with respect to spatially and temporally large scale changes. With the 2015 launch [...] Read more.

With urban populations and their footprints growing globally, the need to assess the dynamics of the urban environment increases. Remote sensing is one approach that can analyze these developments quantitatively with respect to spatially and temporally large scale changes. With the 2015 launch of the spaceborne EnMAP mission, a new hyperspectral sensor with high signal-to-noise ratio at medium spatial resolution, and a 21 day global revisit capability will become available. This paper presents the results of a literature survey on existing applications and image analysis techniques in the context of urban remote sensing in order to identify and outline potential contributions of the future EnMAP mission. Regarding urban applications, four frequently addressed topics have been identified: urban development and planning, urban growth assessment, risk and vulnerability assessment and urban climate. The requirements of four application fields and associated image processing techniques used to retrieve desired parameters and create geo-information products have been reviewed. As a result, we identified promising research directions enabling the use of EnMAP for urban studies. First and foremost, research is required to analyze the spectral information content of an EnMAP pixel used to support material-based land cover mapping approaches. This information can subsequently be used to improve urban indicators, such as imperviousness. Second, we identified the global monitoring of urban areas as a promising field of investigation taking advantage of EnMAP’s spatial coverage and revisit capability. However, owing to the limitations of EnMAPs spatial resolution for urban applications, research should also focus on hyperspectral resolution enhancement to enable retrieving material information on sub-pixel level. Full article

(This article belongs to the Special Issue Urban Remote Sensing)

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Open AccessArticle

Downscaling Pesticide Use Data to the Crop Field Level in California Using Landsat Satellite Imagery: Paraquat Case Study

by Susan K. Maxwell

Remote Sens. 2011, 3(9), 1805-1816; https://doi.org/10.3390/rs3091805 - 25 Aug 2011

Cited by 8 | Viewed by 8192

Abstract

Exposure to pesticides has been associated with increased risk of many adverse health effects. To understand the relationships between pesticide exposure and health outcomes, epidemiologists need information on where pesticides are applied in the environment. California maintains one of the most comprehensive pesticide [...] Read more.

Exposure to pesticides has been associated with increased risk of many adverse health effects. To understand the relationships between pesticide exposure and health outcomes, epidemiologists need information on where pesticides are applied in the environment. California maintains one of the most comprehensive pesticide use reporting systems in the world, yet the data are only recorded at a coarse geographic scale of approximately 2.6 km² area. A method is presented that uses Landsat image time series to downscale California pesticide use data to the crop field-level. The approach is demonstrated using paraquat applied to vineyard and cotton fields. Full article

(This article belongs to the Special Issue Remote Sensing in Public Health)

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Study area. California Central Valley agricultural region (green) with approximate location of study area (black outline). Full article ">Figure 2
System diagram for integrating Landsat image time series, Section-level pesticide use data, and a crop signature library to map pesticide use at the field-level. Full article ">Figure 3
Landsat time series color composite image (left, PCA123) and Normalized Difference Vegetation Index (NDVI) time series plots (right) for selected crop fields within Section 14S17E01. Paraquat was applied to two vineyard fields. Five of the six field units (identified as a white “V” on the image and blue lines in the graph) identified as vineyard on the California Department of Water Resources (CDWR) map had NDVI time series closely matching vineyard library signatures (median ≤ 0.09). One field unit identified as vineyard on the CDWR map appeared to be newly planted (white “V” inside of white box). The difference value was greater for this field (0.17) because the library did not contain signatures for newly planted vineyards. Identification of the specific two fields that were sprayed with paraquat was not possible in this example because more than two fields were identified as vineyards within the Section. Full article ">Figure 4
Landsat time series color composite image (PCA123) and NDVI time series plots for selected crop fields within Section 16S17E01. Paraquat was applied to one cotton field. The field with the closest match to cotton is identified as a white “C” on the image to the left and black line in the graph on the right. Identification of the specific field sprayed with paraquat was possible in this example. Full article ">Figure 5
Landsat time series color composite image (left, PCA123) and NDVI time series plots (right) for all crop fields within Section 17S17E01. Paraquat was applied to one cotton field. Only one field had NDVI time series values similar to cotton (identified as a white “C” on the image to the left and black line in the graph on the right). The specific field where paraquat was applied was correctly identified in this example. Full article ">Figure 6
Landsat time series color composite image (left, PCA123) and NDVI time series plots (right) for all crop fields within Section 18S17E01. Paraquat was applied to two cotton fields. Two fields had NDVI time series values similar to cotton (identified as a white letter “C” on the image and black and purple dashed lines in the graph. Both fields closely matched signatures in the library (median difference ≤ 0.09). The specific fields where paraquat was applied were identifiable in this case. Determining which paraquat application was applied to which cotton field was not possible. Full article ">

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Remote Sens., Volume 3, Issue 9 (September 2011) – 16 articles , Pages 1805-2109

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