7 research outputs found
FUSING OF OPTICAL AND SYNTHETIC APERTURE RADAR (SAR) REMOTE SENSING DATA: A SYSTEMATIC LITERATURE REVIEW (SLR)
Remote sensing and image fusion have recognized many important improvements throughout the recent years, especially fusion of optical and synthetic aperture radar (SAR), there are so many published papers that worked on fusing optical and SAR data which used in many application fields in remote sensing such as Land use Mapping and monitoring. The goal of this survey paper is to summarize and synthesize the published articles from 2013 to 2018 which focused on the fusion of Optical and synthetic aperture radar (SAR) remote sensing data in a systematic literature review (SLR), based on the pre-published articles on indexed database related to this subject and outlining the latest techniques as well as the most used methods. In addition this paper highlights the most popular image fusion methods in this blending type. After conducting many researches in the indexed databases by using different key words related to the topic “fusion Optical and SAR in remote sensing”, among 705 articles, chosen 83 articles, which match our inclusion criteria and research questions as results ,all the systematic study ‘ questions have been answered and discussed
Land Surface Monitoring Based on Satellite Imagery
This book focuses attention on significant novel approaches developed to monitor land surface by exploiting satellite data in the infrared and visible ranges. Unlike in situ measurements, satellite data provide global coverage and higher temporal resolution, with very accurate retrievals of land parameters. This is fundamental in the study of climate change and global warming. The authors offer an overview of different methodologies to retrieve land surface parameters— evapotranspiration, emissivity contrast and water deficit indices, land subsidence, leaf area index, vegetation height, and crop coefficient—all of which play a significant role in the study of land cover, land use, monitoring of vegetation and soil water stress, as well as early warning and detection of forest fires and drought
Semantic location extraction from crowdsourced data
Crowdsourced Data (CSD) has recently received increased attention in many application areas including disaster management. Convenience of production and use, data currency and abundancy are some of the key reasons for attracting this high interest. Conversely, quality issues like incompleteness, credibility and relevancy prevent the direct use of such data in important applications like disaster management. Moreover, location information availability of CSD is problematic as it remains very low in many crowd sourced platforms such as Twitter. Also, this recorded location is mostly related to the mobile device or user location and often does not represent the event location. In CSD, event location is discussed descriptively in the comments in addition to the recorded location (which is generated by means of mobile device's GPS or mobile communication network). This study attempts to semantically extract the CSD location information with the help of an ontological Gazetteer and other available resources. 2011 Queensland flood tweets and Ushahidi Crowd Map data were semantically analysed to extract the location information with the support of Queensland Gazetteer which is converted to an ontological gazetteer and a global gazetteer. Some preliminary results show that the use of ontologies and semantics can improve the accuracy of place name identification of CSD and the process of location information extraction
Comparing synthetic aperture radar and LiDAR for above-ground biomass estimation in Glen Affric, Scotland
Quantifying above-ground biomass (AGB) and carbon sequestration has been a
significant focus of attention within the UNFCCC and Kyoto Protocol for improvement
of national carbon accounting systems (IPCC, 2007; UNFCCC, 2011). A multitude of
research has been carried out in relatively flat and homogeneous forests (Ranson & Sun,
1994; Beaudoin et al.,1994; Kurvonen et al., 1999; Austin et al., 2003; Dimitris et al.,
2005), yet forests in the highlands, which generally form heterogeneous forest cover and
sparse woodlands with mountainous terrain have been largely neglected in AGB studies
(Cloude et al., 2001; 2008; Lumsdon et al., 2005; 2008; Erxue et al., 2009, Tan et al.,
2010; 2011a; 2011b; 2011c; 2011d). Since mountain forests constitute approximately
28% of the total global forest area (Price and Butt, 2000), a better understanding of the
slope effects is of primary importance in AGB estimation. The main objective of this
research is to estimate AGB in the aforementioned forest in Glen Affric, Scotland using
both SAR and LiDAR data.
Two types of Synthetic Aperture Radar (SAR) data were used in this research:
TerraSAR-X, operating at X-band and ALOS PALSAR, operating at L-band, both are
fully polarimetric. The former data was acquired on 13 April 2010 and of the latter, two
scenes were acquired on 17 April 2007 and 08 June 2009. Airborne LiDAR data were
acquired on 09 June 2007. Two field measurement campaigns were carried out, one of
which was done from winter 2006 to spring 2007 where physical parameters of trees in
170 circular plots were measured by the Forestry Commission team. Another intensive
fieldwork was organised by myself with the help of my fellow colleagues and it
comprised of tree measurement in two transects of 200m x 50m at a relatively flat and
dense plantation forest and 400m x 50m at hilly and sparse semi-natural forest. AGB is
estimated for both the transects to investigate the effectiveness of the proposed method
at plot-level. This thesis evaluates the capability of polarimetric Synthetic Aperture Radar data
for AGB estimation by investigating the relationship between the SAR backscattering
coefficient and AGB and also the relationship between the decomposed scattering
mechanisms and AGB. Due to the terrain and heterogeneous nature of the forests, the
result from the backscatter-AGB analysis show that these forests present a challenge for
simple AGB estimation. As an alternative, polarimetric techniques were applied to the
problem by decomposing the backscattering information into scattering mechanisms
based on the approach by Yamaguchi (2005; 2006), which are then regressed to the field
measured AGB. Of the two data sets, ALOS PALSAR demonstrates a better estimation
capacity for AGB estimation than TerraSAR-X. The AGB estimated results from SAR
data are compared with AGB derived from LiDAR data. Since tree height is often
correlated with AGB (Onge et al., 2008; Gang et al., 2010), the effectiveness of the tree
height retrieval from LiDAR is evaluated as an indicator of AGB. Tree delineation was
performed before AGB of individual trees were calculated allometrically. Results were
validated by comparison to the fieldwork data. The amount of overestimation varies
across the different canopy conditions. These results give some indication of when to
use LiDAR or SAR to retrieve forest AGB. LiDAR is able to estimate AGB with good
accuracy and the R2 value obtained is 0.97 with RMSE of 14.81 ton/ha. The R2 and
RMSE obtained for TerraSAR-X are 0.41 and 28.5 ton/ha, respectively while for ALOS
PALSAR data are 0.70 and 23.6 ton/ha, respectively. While airborne LiDAR data with
very accurate height measurement and consequent three-dimensional (3D) stand profiles
which allows investigation into the relationship between height, number density and
AGB, it's limited to small coverage area, or large areas but at large cost. ALOS
PALSAR, on the other hand, can cover big coverage area but it provide a lower
resolution, hence, lower estimation accuracy
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The Changing Matrix: Reforestation and Connectivity in a Tropical Habitat Corridor
In the last two decades, export-oriented crops and timber and fruit plantations have joined small-scale cultivation and pasture as important causes of tropical deforestation. Widespread conversion of tropical forest to agriculture threatens to isolate protected areas, which has led to efforts to maintain functional connectivity in landscapes between protected areas. Relatively few "landscape conservation" efforts have been assessed for their effect on deforestation, but advances in remote sensing now permit detailed monitoring of tropical land uses over time, including mapping of tree crops and plantations. This dissertation evaluates the long-term impact of forest conservation and reforestation policies on tropical forests in a habitat corridor. The following chapters test the capability of remote sensing to monitor tropical conservation efforts and assess whether landscape conservation policies can maintain forest cover and connectivity in the face of rapid agricultural expansion. Costa Rica has one of the most comprehensive landscape conservation policies in the tropics: a 1996 Forest Law banned deforestation and expanded payments for environmental services (PES) to protect forests and plant trees, prioritizing designated habitat corridors between protected areas. The long-term effect of the program on land-use transitions is not well known. To take advantage of this regional policy experiment, I used a time-series of five moderate-resolution Landsat images to track land-use change from 1986 to 2011in the oldest habitat corridor, the San Juan-La Selva Biological Corridor (SJLSBC). Forest conservation policies were associated with a 40% decline in deforestation after 1996 despite a doubling in the area of cropland in the last decade. The proportion of cropland derived from mature forest dropped from 16.4% to 1.9% after 1996, while one fifth of pasture expansion continued to be derived from mature forest. These results suggest that forest conservation policies can successfully lower deforestation, and that they can be more effective with large export producers than small-scale cattle producers. Tree plantations are an important component of Costa Rican PES, but knowledge of their distribution and contribution to connectivity in the corridor region is poor. After reviewing the remote sensing literature, I employed a novel integration of hyperspectral images and a Landsat time-series to create the first regional map of tropical tree plantation species. Including multitemporal data significantly improved overall hyperspectral map accuracy to 91%; the six tree plantation species were classified with 83% mean producer's accuracy. Non-native species made up 89% of tree plantations, and they were cleared more rapidly than native tree plantations and secondary forests. I combined existing land cover maps, field behavioral experiments, and a graph connectivity model to estimate whether landscape conservation policies increased connectivity for understory insectivorous birds, a representative forest-dependent group. The field playback experiments indicated both native and exotic tree plantations with a dense shrubby understory were acceptable dispersal habitat for all species, and that birds traveled readily near secondary forest edges but rarely into forested pasture. Graph model parameters were informed by these results. For all of these bird species, functional connectivity declined by 14-21% with only a 4.9% decline in forest area over time, implying that conservation policies have not caused a net increase in functional connectivity in the SJLSBC region. Despite making up 2% of the region, tree plantations had little effect on regional connectivity because of their placement in the landscape; we demonstrate that spatially-targeted reforestation of 0.1% of the region could increase connectivity by 1.8%. Collectively, the results presented in these chapters underline the potential and limitations of landscape conservation policies and corridor plans in the tropics; combining regulations and PES can lower deforestation over the medium-term, but increased enforcement, improved monitoring with remote sensing, and targeted conservation effort is needed to combat illegal deforestation and restore functional connectivity. Given numerous new tropical corridor and PES programs and the qualified successes of landscape conservation policies in Costa Rica and other tropical countries, our approach to the analysis can be applied to monitor and evaluate connectivity across the tropics
An Investigation on Benefit-Cost Analysis of Greenhouse Structures in Antalya
Significant population increase across the world, loss of cultivable land and increasing demand for food put pressure on agriculture. To meet the demand, greenhouses are built, which are, light structures with transparent cladding material in order to provide controlled microclimatic environment proper for plant production. Conceptually, greenhouses are similar with manufacturing buildings where a controlled environment for manufacturing and production have been provided and proper spaces for standardized production processes have been enabled. Parallel with the trends in the world, particularly in southern regions, greenhouse structures have been increasingly constructed and operated in Turkey. A significant number of greenhouses are located at Antalya. The satellite images demonstrated that for over last three decades, there has been a continuous invasion of greenhouses on all cultivable land. There are various researches and attempts for the improvement of greenhouse design and for increasing food production by decreasing required energy consumption. However, the majority of greenhouses in Turkey are very rudimentary structures where capital required for investment is low, but maintenance requirements are high when compared with new generation greenhouse structures. In this research paper, life-long capital requirements for construction and operation of greenhouse buildings in Antalya has been investigated by using benefit-cost analysis study
Knowledge Capturing in Design Briefing Process for Requirement Elicitation and Validation
Knowledge capturing and reusing are major processes of knowledge management that deal with the elicitation of valuable knowledge via some techniques and methods for use in actual and further studies, projects, services, or products. The construction industry, as well, adopts and uses some of these concepts to improve various construction processes and stages. From pre-design to building delivery knowledge management principles and briefing frameworks have been implemented across project stakeholders: client, design teams, construction teams, consultants, and facility management teams. At pre-design and design stages, understanding the client’s needs and users’ knowledge are crucial for identifying and articulating the expected requirements and objectives. Due to underperforming results and missed goals and objectives, many projects finish with highly dissatisfied clients and loss of contracts for some organizations. Knowledge capturing has beneficial effects via its principles and methods on requirement elicitation and validation at the briefing stage between user, client and designer. This paper presents the importance and usage of knowledge capturing and reusing in briefing process at pre-design and design stages especially the involvement of client and user, and explores the techniques and technologies that are usable in briefing process for requirement elicitation