ID: 53887
Title: Study of normalized difference vegetation index variation and its correlation with climate factors in the three-river-source region
Author: Meng Qi Hu, Fei Mao, Han Sun, Ying Yu Hou
Editor: Alfred Stein
Year: 2011
Publisher: Elsevier, Vol 13, Issue 1, February 2011
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: NDVI, climate factors, Three-river-source region China
Abstract: Using NOAA/AVHRR 10-day composite NDVI data and 10 -day meterological data, including air temperature, precipitation, vapor pressure, wind velocity and sunshine duration, at 19 weather stations in the three-river-source region in the Qinghai-Tibetan Plateau in China from 1982 to 2000, the variations of NDVI and climate factors were analyzed for the purpose of studying the correlation between climate change and vegetation growth as represented by NDVI in this region. Results showed that the NDVI values in this region gradually grew from the west to the east, and the distribution was consistent with that of moisture status. The growing season came earlier due to climate warming, yet because of the reduction of precipitation, maximal NDVI during 1982-2000 did not show a significant change. NDVI related positively to air temperature, vapor pressure and precipitation, but negatively related to sunshine duration and wind velocity. Furthermore, the response of NDVI to climate change showed time lags for different climate factors. Water condition and temperature were found to be the most important factors effecting the variation of NDVI during the growing season in both the semi-arid and the semi-humid areas. In addition, NDVI had a better correlation with vapor pressure than with precipitation. The ratio of precipitation to evapotranspiration, representing water gain and loss, can be regarded as a comprehensive index to analyze NDVI and climate change, especially in areas where the water condition plays a dominant role.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53886
Title: Detection and estimation of mixed paddy rice cropping patterns with MODIS data
Author: Dailiang Peng, Alfredo R. Huete, Jingfeng Huang, Fuming Wang, Huasheng Sun
Editor: Alfred Stein
Year: 2011
Publisher: Elsevier, Vol 13, Issue 1, February 2011
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: Flooded paddy rice, MODIS, Land surface water index, Enhanced Vegetation Index, Phenology
Abstract: In this paper, we developed a more sophisticated method for detection adn estimation of mixed paddy rice agriculture from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data. Previous research demonstrated that MODIS data can be used to map paddy rice fields and to distinguish rice from other crops at large, continental scales with combined Enhanced Vegetation Index (EVI) and Land Surface Water Index (LSWI) analysis during the flooding and rice transplanting stage. Our approach improves upon this methodology by incorporating mixed rice cropping patterns that include single-season rice crops, early-season rice, and late-season rice cropping systems. A variable EVI/LSWI threshold function, calibrated to more local rice management practices, was used to recognize rice fields at the flooding stage. We developed our approach with MODIS data in Hunan Province, China, an area with significant flooded paddy rice agriculture and mixed rice cropping patterns. We further mapped the aerial coverage and distribution of early, late, and single paddy rice crops for several years from 2000 to 2007 in order to quantify temporal trends in rice crop coverage, growth nad management systems. Our results were validated with finer resolution (2.5 m) Satellite Pour 1 ' Observation de la Terre 5 High Resolution Geometric (SPOT 5 HRG) data, land-use data at teh scale of 1/10,000 and with country-level rice area statistical data. The results showed that all three paddy rice crop patterns could be discriminated and their spatial distribution quantified. We showed that all three paddy rice crop patterns could be discriminated and their spatial distribution quantified. We show the area of single crop rice to have increased annually and almost doubling in extent from 2000 to 2007, with simultaneous, but unique declines in the extent of early and late paddy rice. These results were significantly positive correlated and consistent with agricultural statistical data at the country level (P<0.01).
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53885
Title: Mexico city subsidence observed with persistent scatterer InSAR
Author: Batuhan Osmanoglu, Timothy H. Dixon, Shimon Wdowinski, Enrique Cabral-Cano, Yan Jiang
Editor: Alfred Stein
Year: 2011
Publisher: Elsevier, Vol 13, Issue 1, February 2011
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Applied Earth Observation and Geoinformation
Keywords: Subsidence, Interferometry, GPS, Mexico city, Synthetic aperture radar (SAR), Interferometry, persistent scatterer interferometry (PSI)
Abstract: We analyzed 23 satellite SAR (synthetic aperture radar) scenes using Persistent Scatter Interferometry (PSI) to study subsidence in Mexico City associated with groundwater withdrawal. The data were acquired by the Envisat ASAR system between January 2004 and July 2006. The spatial patterns of subsidence and the maximum subsidence rate (300 mm/year) are similar to earlier studies. Comparison to independent GPS data indicates RMS agreement between the two techniques of 6.9 mm/year, about the level expected based on joint data uncertainty. Significant annual variation in the GPS vertical data is not observed, suggesting minimal aquifer recharge during the rainy season, and justifying a simple linear model of phase variation through time for the PSI analysis.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53884
Title: Deciduous Forest biomass and structure analysis using Microwave Remote Sensing
Author: N. Vyjayanthi, Dheeraj Kumar Yadav, Dr. C.S.Jha, Dr. Lalji Singh, Dr. M.S.R.Murthy
Editor: None
Year: 2010
Publisher: National Remote Sensing Centre, Feb 2010
Source: Centre for Ecological Sciences
Reference: None
Subject: Deciduous Forest biomass and structure analysis using Microwave Remote Sensing
Keywords: Above ground biomass, ASAR, DLR-ESAR, Vegetation classification, coherence Polarimetric signatures and Polarimetric decompositions
Abstract: The RISAT-JEP program for forestry applications was undertaken by NRSC, Forestry and Ecology Division as a pilot campaign with specific objectives of above ground biomass estimation and vegetation type classification. This document discusses the different techniques such as multi-sensor fusion, texture measures, interferometric coherence, polarimetric signatures, and polarimetric decompositions etc. which were used to characterize different biomass ranges of the study areas and to classify the major land cover classes. The study has its uniqueness and gains importance in the application potential of SAR data over tropical regions like India, both in terms of complementary/supplementary to optical data sets due to persisting cloud cover and to the lack of availability of any earlier scientific work over the study region. The study would facilitate futrue research in tropical regions to enhance the potentials of SAR data in land cover classification and above ground biomass estimation.
Location: 215
Literature cited 1: None
Literature cited 2: None
ID: 53883
Title: Biodiversity Characterisation at Landscape Level using Remote Sensing & Geographic Information System -Manual
Author: Dr. P.S. Roy, Dr. M.S.R.Murthy, Dr. Sarnam Singh, Dr. C.S.Jha, Dr. M.C.Porwal, Dr. Subhash Ashutosh, Dr. S.P.S Kushwaha, Dr.Ch.Sudhakar Reddy, Shri G.S.Pujar, Ms. Shivam Trivedi, Dr. Arijit Roy, Shri Harish Karnatak, Dr. M.M.Kimothi, Dr. Mukund Behe
Editor: None
Year: 2008
Publisher: National Remote Sensing Centre, Dec 2008, Manual
Source: Centre for Ecological Sciences
Reference: None
Subject: Biodiversity Characterisation at Landscape Level using Remote Sensing & Geographic Information System
Keywords: Biodiversity characterisation, landscape ecology, remote sensing, GIS, spatial analysis, modeling, geodatabase, web-enabled information systems
Abstract: The manual discusses overall methodology for landscape level characterization of biodiversity using remote sensing and GIS. It covers various aspects including project background, multiseason data classification, stratified phytosociological sampling and analysis for diversity trends, landscape level modeling using customized GIS environment, spatial analysis, quality evaluation, geodatabase creation and web-enabled systems for outreach.
Location: 215
Literature cited 1: None
Literature cited 2: None
ID: 53882
Title: Complex-valued multi-layer perceptrons-An application to polarimetric SAR data
Author: Ronny Hansch
Editor: Russell G. Congalton
Year: 2010
Publisher: Asprs, Vol 76, No 9, September 2010
Source: Centre for Ecological Sciences
Reference: None
Subject: Photogrammetric Engineering & Remote Sensing
Keywords: Multi-Layer Perceptrons (MLPs), polarimetric synthetic aperture radar (POLSAR), complex-valued MLPs (CV-MLPs),
Abstract: Multi-Layer Perceptrons (MLPs) are powerful function approximators. In the last decades they were successfully applied to many different regression and classification problems. Their characteristics and convergence properties are well studied and relatively well understood, but they were originally designed to work with real-valued data. The main focus of this paper is the classification of polarimetric synthetic aperture radar (POLSAR) data which are a complex-valued signal. Instead of using an arbitrarily projection of this complex-valued data to the real domain, the paper proposes the usage of complex-valued MLPs (CV-MLPs), which are an extension of MLPs to the complex domain. The paper provides a detailed yet general derivation of the complex backpropagation algorithm and mentions related problems as well as possible solutions. Furthermore, it evaluates the performance of CV-MLPs in a land-cover classification task in POLSAR images under several learning conditions, and compares the proposed classifier with standard methods. The experimental results show that CV-MLPs are successfully applicable to classification tasks in POLSAR data. They show good convergence properties and a better performance if compared to real-valued MLPs.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53881
Title: Extraction and geometrical accuracy of double-bounce lines in high resolution SAR images
Author: Jan Dirk Wegner, Stefan Auer, and Uwe Soergel
Editor: Russell G. Congalton
Year: 2010
Publisher: Asprs, Vol 76, No 9, September 2010
Source: Centre for Ecological Sciences
Reference: None
Subject: Photogrammetric Engineering & Remote Sensing
Keywords: TerraSAR-X, SAR images, Gaussian functions model
Abstract: In TerraSAR-X spotlight data features of man-made objects in urban areas become visible. In a case study, this paper presents results of a precision and geometrical accuracy investigation of extracted double-bounce lines in SAR images. Two TerraSAR-X (TSX) acquisitions of a complex urban scene are compard to simulated SAR images. Using a new line detection method, double-bounce lines are extracted from simulated and real imagery with sub-pixel accuracy. The deviation of an extracted double-bounce line polygon with regard to both an interpolated line and ground truth is analyzed and discussed. First, it is shown that Gaussian functions model the deviation of the interpolated line from the polygon sufficiently well. Second, the absolute geometrical accuracy of the extracted double-bounce lines is evaluated with respect to ground truth. Results of the case study confirm that double-bounce lines provide reliable geometrical information, for instance, for building extraction and SAR image classification.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53880
Title: Persistent scatterer interferometry: potential, limits and initial C- and X-band comparison
Author: M. Crosetto, O. Monserrat, R. Iglesias, and B. Crippa
Editor: Russell G. Congalton
Year: 2010
Publisher: Asprs, Vol 76, No 9, September 2010
Source: Centre for Ecological Sciences
Reference: None
Subject: Photogrammetric Engineering & Remote Sensing
Keywords: Persistent Scatterer Interferometry (PSI), TerraSAR -X sensor, C-and X-band
Abstract: This paper is focussed on the potential and limits of a powerful remote sensing technique used to measure deformation phenomena. It only refers to satellite-based PSI techniques, focusing on the most important sources of C-band SAR data: ERS and Envisat. In addition, it compares C-and X-band results, condering data from the high-resolution . The paper begins with a description of the main characteristics of PSI. It then discusses teh most important PSI products and their performances, analyzing their spatial sampling, the so-called residual topographic error and PSI geocoding, the average displacement rates, and the deformation time series. As C-band products are concerned, the apper reports some relevant PSI validation results, which come from the ESA-funded Terrafirma Validation Project. Regarding the X-band, it describes the results obtained over the City of Barcelona by processing 13 TerraSAR-X images. The last part discusses the main limits of PSI.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53879
Title: Investigations on surface reflection models for intensity normalization in Airborne Laser Scanning (ALS) data
Author: Boris Jutzi and Hermann Gross
Editor: Russell G. Congalton
Year: 2010
Publisher: Asprs, Vol 76, No 9, September 2010
Source: Centre for Ecological Sciences
Reference: None
Subject: Photogrammetric Engineering & Remote Sensing
Keywords: Lambertian,extended Lambertian, Phong reflection model, standard Lambertian reflection model
Abstract: The analysis of laser scanner data is of great interest for gaining geospatial information. Especially for segmentation, classification, or visualization purposes, the intensity measured with a laser scanner device can be helpful. For automatic intensity normalization, various aspects are of concern, like beam divergence and atomospheric attenuation, both depending on the range. Additionally, the intensity is influenced by the incidence angle between beam propagation direction and surface orientation. To gain the surface orientation, the eigenvectors of the covariance matrix for object points within a nearby environment are determined. After normalization the intensity does no longer depend on the incidence angle and is influenced by the material of the surface only. For surface reflection modeling, (a) the Lambertian, (b) the extended Lambertian, and (c) the Phong reflection model are introduced, to consider diffuse and specular backscattering characteristics of the surface. An airborne measurement campaign was carried out to investigate the influences of the incidence angle on the measured intensity. For investigations, 17 urban areas, such as traffic, building, and vegetation regions were studied and the derived improvements are depicted. The investigation shows that large intensity variation caused by the object surface orientation and the distance between sensor and object can be normalized by utilizing the standard Lambertian reflection model.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53878
Title: Comparison of matching algorithms for DSM generation in urban areas from Ikonos imagery
Author: Abdalla Alobeid, Karsten Jacobsen, and Christian Heipke
Editor: Russell G. Congalton
Year: 2010
Publisher: Asprs, Vol 76, No 9, September 2010
Source: Centre for Ecological Sciences
Reference: None
Subject: Photogrammetric Engineering & Remote Sensing
Keywords: least squares matching (LSM), dynamic programming (DP), semigold matching (SGM)
Abstract: The extraction of the third dimension from remote sensing data is a well known technique. Since in a number of countries aerial images and laser scanner data are unavailable, expensive or classified, stereoscopic high-resolution optical satellite images provide a viable alternative for generating digital surface and digital terrain models. Especially the automatic extraction of highly accurate 3D surface models in urban areas is still a very complicated task due to occlusions, large differences in height and the variety of objects and surface material.
In this paper an analysis and a visual and quantitative comparison of three different matching algorithms for generating urban DSMs based on very high-resolution satellite images is presented. The three algorithms are least squares matching (LSM) in a region growing fashion, dynamic programming (LSM) in a region growing fashion, dynamic programming (DP) and semigold matching (SGM). The characteristics of the three algorithms as applied to four different Ikonos stereo pairs with a ground sampling distance of 1 m are shown. The following results were obtained: visually, in the LSM results the shape of the buildings is considerably smoothed. While in the DP results the building shape is sharper, only little detail is visible on the building roofs, and streaking along teh epipolar lines causes problems. With SGM more details can be extracted and the results visually have the best quality. Based on reference data for the different test sites, the standard deviation of the building heights determined by LSM and DP is in the range of one pixel or slightly better, while it is in the range of half a pixel for SGM.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53877
Title: New era of cartosat satellites for large scale mapping
Author: P.V.Radhadevi, S.S.Solanki, V.Nagasubramanian, Archana Mahapatra, D. Sudheer Reddy, M.V.Jyothi, Krishna Sumanth, J. Saibaba and Geeta Varadan
Editor: Russell G. Congalton
Year: 2010
Publisher: Asprs, Vol 76, No 9, September 2010
Source: Centre for Ecological Sciences
Reference: None
Subject: Photogrammetric Engineering & Remote Sensing
Keywords: Cartosat-1, Cartosat-2, DEM
Abstract: Important considerations for large scale mapping from satellite images are information content and geometric fidelity. Cartosat series of satellites with stereo mapping capability have become the mainstay towards large scale mapping for urban and rural applications. Algorithms for processing of high-resolution Indian remote sensing satellite data has been developed at ADRIN and is used for operational generation of data products. Variations in the sensor model with respect to teh viewing geometries of Cartosat-1 and Cartosat-2 are explained in the paper. Finally, an assessment of the mapping potential of the satellites is discussed. The geometric accuracy achieved from Cartosat-1 and Cartosat-2 images over the same checkpoints are compared. DEM, geometric accuracy, and capability for topographic feature capture are good enough for making 1:10 000 and 1:7000 scale maps from Cartosat-1 and Cartosat-2, respectively. Based on the error estimation and analysis, it is concluded that if the strict photogrammetric processing model are ground control points are employed, high-resolution satellite imagery can be used for the generation and update of topographic maps of scale 1:10 000 and larger.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53876
Title: DGPF project: Evaluation of digital photogrammetric aerial-based imaging systems-Overview and results from the Pilot center
Author: Michael Cramer and Norbert Haala
Editor: Russell G. Congalton
Year: 2010
Publisher: Asprs, Vol 76, No 9, September 2010
Source: Centre for Ecological Sciences
Reference: None
Subject: Photogrammetric Engineering & Remote Sensing
Keywords: Photogrammetric digital airborne camera systems, Digital Surface Model (DSM)
Abstract: Within this paper, results of a test on the evaluation of the most recent photogrammetric digital airborne camera systems are presented. This project was initiated by the German Society of photogrammetry, Remote Sensing and Geoinformation (DGPF), based on data from 12 different digital sensor systems flown in a well-controlled test site. The main topics of the evaluation phase are the analysis of geometric accuracy and sensor calibration, the radiometric performance including on-site radiometric calibration and multi-spectral land classifications, the performance of photogrammetric Digital Surface Model (DSM) generation, and the potential of manual steroplotting from digital images. Within this paper, only results obtained at the Institute of Photogrammetry (IFP), Universitaet Stuttgart will be presented, comprehensively providing the high performance of digital camera systems and processing. The IFP served as digital camera systems and processing. The IFP served as the pilot camera systems and processing. The IFP served as the pilot center and additionally concentrated on the investigation of camera geometry and the image based generation of height data.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53875
Title: Triangulating the past-recovering Portugal ' s aerial images repository
Author: Paula Redweik, Dora Rogue, Antonio Marques, Rita Matildes, and Fernando Marques
Editor: Russell G. Congalton
Year: 2010
Publisher: Asprs, Vol 76, No 9, September 2010
Source: Centre for Ecological Sciences
Reference: None
Subject: Photogrammetric Engineering & Remote Sensing
Keywords: photo-geographic database, IGEOE
Abstract: Although traditional and web map producers strive to deliver up-to-date products and old aerial photographs do not fit in their concept, other users are rather interested in old aerial images and in temporal series. In Portugal, aerial, surveys for mapping purposes started by the late thirties of the twentieth century as documented by the oldest existing aerial photos collection in the archives of the IGEOE in Lisbon. Being the oldest visual witnesses of the country, the relevance of the information they contain is unquestionable. The objective of this project is the recovery of an important national aerial photographic heritage hibernating in analogue format in the archives. In a test block, strategies to recover radiometry and spatial orientation were developed and successfully tested in order to make the photos accessible and workable by the modern scientific community and by the general public. A photo-geographic database has also been organized and made available.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53874
Title: Linearization of NDVI based on its relationship with vegetation fraction
Author: Zhangyan Jiang and Alfredo R. Huete
Editor: Russell G. Congalton
Year: 2010
Publisher: Asprs, Vol 76, No 8, August 2010
Source: Centre for Ecological Sciences
Reference: None
Subject: Photogrammetric Engineering & Remote Sensing
Keywords: Normalized Difference Vegetation Index (NDVI)
Abstract: The Normalized Difference Vegetation Index (NDVI) is widely used for global monitoring of land surface vegetation dynamics from space. However, it is well documented that the NDVI approaches saturation asymptotically over highly vegetated areas. In this study, a linearized NDVI (LNDVI) is derived by introducing a linearity-adjustment factor, ? , into the NDVI equation to improve the linearity of the relationship with vegetation fraction and mitigate the saturation problem encountered by NDVI. The linearity of the LNDVI is demonstrated using a ground-observed data set and a model-simulated data set. A functional relationship and consistence of LNDVI with other NDVI adaptations are found, providing independent justification of the value of the NDVI adaptations. Due to its improved linearity with vegetation fraction, this index would provide more accurate monitoring of vegetation dynamics and estimation of biophysical parameters. The LNDVI can be derived from historical NDVI datasets directly without without knowledge of input reflectances.
Location: 231
Literature cited 1: None
Literature cited 2: None
ID: 53873
Title: Combining Aerial photogrammetry and Terrestrial Lidar for reservior Analog modelling
Author: Simon J. Buckley, Ernesto Schwarz, Viktor Terlaky, John A. Howell, and R.W.(Bill) Arnott
Editor: Russell G. Congalton
Year: 2010
Publisher: Asprs, Vol 76, No 8, August 2010
Source: Centre for Ecological Sciences
Reference: None
Subject: Photogrammetric Engineering & Remote Sensing
Keywords: Terrestrial lidar, geocellular model
Abstract: High-resolution aerial photography was captured covering a geological outcrop at Castle Creek, British Columbia, Canada. Here, for the purpose of hydrocarbon analog modeling, the outcrop was required to be accurately surveyed, so that key stratigraphic surfaces could be mapped in three dimensions. Becasue the outcrop strata were vertically orientated, these surfaces could be tracked over a wide area; however, to provide a true reconstruction of the geology, it was necessary to also model localized vertical cliffs providing a cross-section through the stratigraphy. Terrestrial lidar was utilized to cover these cliff sections which were poorly represented in the 2.5D aerial data. The integrated outcrop surface was textured with metric aerial and terrestrial imagery providing a photorealistic model that could be used for interpretation by geologists. This formed the basis for building a geocellular model of the geological volume, which was used to assist in the understanding of subsurface reservoirs where data are often limited.
Location: 231
Literature cited 1: None
Literature cited 2: None