Geospatial Modelling and Mapping of Snow Avalanche Susceptibility

The main objective of this study was to mapping the potential avalanche susceptible zones in Siachen region of the Western Indian Himalaya. A geospatial analytical hierarchy process (AHP) model based on expert judgements has been applied in this study. Five most important terrain based avalanche occurrence parameters including slope, aspect, curvature, elevation and ground cover are employed in the present model. The ASTER GDEM and Landsat 8 OLI imagery are used to generate the avalanche occurrence parameters. A pairwise comparison matrix is computed to estimate the weight values for input terrain parameters. These weight values are then assigned to each respective avalanche occurrence parameter and employed in a geospatial AHP model to generate an avalanche susceptibility map. Finally, an avalanche inventory has been utilized to validate the results. The avalanche susceptibility map has been compared with the avalanche inventory map by calculating the area under the receiver operating characteristics curve (ROC-AUC) technique.     

Use of Remote Sensing and Geographical Information System in the delineation and characterization of ground water prospect zones

The present study was carried out to delineate and characterize ground water prospect zones using IRS-ID LISS-III geocoded data on 1:50,000 scale. The information on lithology, structure, geomorphology and hydrology were generated and integrated to prepare ground water prospect map for a region in western Rajasthan. The information on nature and type of aquifer, type of wells, depth range, yield range, success rate and sustainability were supplemented to form a good database for identification of favourable zone. Geographical Information system (GIS) was used to prepare database on the above layers, analysis of relationship and integrated map preparation. The study area has a complex geomorphology. The geology is dominated by rocks of post Delhi Intrusive and Quaternary sediments. On the basis of hydrogeology and geomorphic characteristics, four categories of ground water prospect zones: high, moderate, low and very low ere delineated. The high prospect zones are alluvial plains and valley fills mainly influenced by quaternary formations with yield expectation between 100-200 lpm. The moderate zone has pediment surfaces covered by shallow soil cover in addition to weathered and fractured aquifer material with expected yield of water between 50-100 lpm. The low potential zones mainly comprise inselbergs and rocky surface with expected discharge below 50 lpm. The very low prospect zones act as run-off generating zones.     

GIS-based MCDA–AHP modelling for avalanche susceptibility mapping of Nubra valley region,Indian Himalaya

Avalanches are behind the majority of fatalities and heavy damage to property in snow-covered mountainous terrain like Himalaya. Recognizing avalanche susceptible areas and publication of avalanche susceptibility maps assist decision-makers and planners to execute suitable measures to reduce the avalanche risk. The present study is an attempt to prepare an avalanche susceptibility map of the Nubra valley region using multi-criteria decision analysis–analytical hierarchy process model in GIS environment. The most prominent avalanche occurrence factors used in this model are slope, aspect, curvature, elevation, terrain roughness and ground cover. ASTER GDEM V2 and Landsat 8 satellite imagery were used to generate considered factors. For validation of the results, prediction rate/accuracy is calculated using the avalanche inventory map of documented avalanche locations. To calculate the prediction accuracy, area under the ROC curve (ROC-AUC) method has been used. The prediction accuracy of the validation results using ROC-AUC shows 91%.     

The Impact of Global/Local Bias on Task-Solving in Map-Related Tasks Employing Extrinsic and Intrinsic Visualization of Risk Uncertainty Maps

The form of visual representation affects both the way in which the visual representation is processed and the effectiveness of this processing. Different forms of visual representation may require the employment of different cognitive strategies in order to solve a particular task; at the same time, the different representations vary as to the extent to which they correspond with an individual’s preferred cognitive style. The present study employed a Navon-type task to learn about the occurrence of global/local bias. The research was based on close interdisciplinary cooperation between the domains of both psychology and cartography. Several different types of tasks were made involving avalanche hazard maps with intrinsic/extrinsic visual representations, each of them employing different types of graphic variables representing the level of avalanche hazard and avalanche hazard uncertainty. The research sample consisted of two groups of participants, each of which was provided with a different form of visual representation of identical geographical data, such that the representations could be regarded as ‘informationally equivalent’. The first phase of the research consisted of two correlation studies, the first involving subjects with a high degree of map literacy (students of cartography) (intrinsic method: N?=?35; extrinsic method: N?=?37). The second study was performed after the results of the first study were analyzed. The second group of participants consisted of subjects with a low expected degree of map literacy (students of psychology; intrinsic method: N?=?35; extrinsic method: N?=?27).The first study revealed a statistically significant moderate correlation between the students’ response times in extrinsic visualization tasks and their response times in a global subtest (r?=?0.384, p?<?0.05); likewise, a statistically significant moderate correlation was found between the students’ response times in intrinsic visualization tasks and their response times in the local subtest (r?=?0.387, p?<?0.05). At the same time, no correlation was found between the students’ performance in the local subtest and their performance in extrinsic visualization tasks, or between their scores in the global subtest and their performance in intrinsic visualization tasks. The second correlation study did not confirm the results of the first correlation study (intrinsic visualization/‘small figures test’: r?=?0.221; extrinsic visualization/‘large figures test’: r?=?0.135). The first phase of the research, where the data was subjected to statistical analysis, was followed by a comparative eye-tracking study, whose aim was to provide more detailed insight into the cognitive strategies employed when solving map-related tasks. More specifically, the eye-tracking study was expected to be able to detect possible differences between the cognitive patterns employed when solving extrinsic- as opposed to intrinsic visualization tasks. The results of an exploratory eye-tracking data analysis support the hypothesis of different strategies of visual information processing being used in reaction to different types of visualization.     

Evaluation of Ground Water Potential Zones Using Remote Sensing Data -A Case Study of Gaimukh Watershed, Bhandara District, Maharashtra

In the present study efforts have been made to evaluate ground water potential zones for ground water targeting using IRS-IC LISS-II1 geo-coded data on 1:50,000 scale. The drainage, geology, geomorpholgoy and lineament information has been generated and integrated to evaluate hydro-geomorphological characteristics of the Gairnukh watershed, Bhandara district, Maharashtra for delineation of ground water potential zones. The analysis reveals that the deep valley fills with thick alluvium have excellent, shallow valley tills and deeply weathered pediplains with thin alluvium have very good and moderately weathered pediplains in the geological formations of Tirodi Gneiss and Sausar Groups have god ground water potential and these units are highly favourable for ground water exploration and development. Shallow weathered pediments in geological formations of Tirodi Gnesis and Sausar Groups are marked under moderate ground water potential zone. Shallow weathered pediplains in geological formations of Tiridi Gneiss and Sausor Groups are grouped under limited ground water potential category, except along the fractures/lineaments. Structural hills in geological formations of Tirodi Gneiss and Sausar Groups have poor ground water prospects. Inselbergs and Linear ridges in geological formations of Tirodi Gneiss are grouped under very poor ground water prospects zone. The good inter-relationship was found among the geological units, geomorphological units, lineament density, hydro-geomorphological zones and ground water yield data.     

A rapid method to assess fire-related debris flow hazard in the Mediterranean region: An example from Sicily (southern Italy)

Increased atmospheric temperatures during the high-pressure which characterise the Mediterranean climate in the dry summer time, coupled with an increase in the intensity of storms in the following wet season over recent years, increase the risk of summer fires as well as debris flows and floods in the autumn and/or in the following years. In addition, the diffuse urbanization of Italy requires a rapid and reliable tool be available in order to obtain preliminary information, at the end of the summer season, that identifies newly fired areas that present a significant hazard to human populations. In such burned zones, soil instability may be more severe favouring debris flows which may impact on populated zones. Thus, in this paper we discuss a rapid methodology to: (i) identify burned areas using band ratio's using multitemporal LANDSAT ETM images; (ii) evaluate the potential of the burned areas as the source of debris flows based on morphometric parameters (slope and hill slope curvature); (iii) evaluate the structures, such as houses and roads, exposed to potential damage by debris flows. Hazardous areas were evaluated using a stochastical model coupled with an empirical relationship which accounts for the mobility of the debris flows. The methodology provides a classification of the most “dangerous” burned areas and the potentially maximum inundated downslope areas. This has been applied to Sicily for the period autumn 2001–autumn 2002. The total burned area was 76.37 km². According to the classification proposed 6.4% of the burned areas were consider of very high to high hazard potential, 54.4% of medium hazard and 43.2% of low hazard potential.     

MAPPING THE AVALANCHE HAZARD FOR MOUNTAINOUS AREAS OF AFGHANISTAN

The authors describe a procedure for the compilation of maps of the avalanche hazard in high-mountain regions of Afghanistan. The basic sources of information include space imagery (photographs and scanner imagery), weather station data, and other geographic information on relief, elevation, location of moisture sources, etc. The methodology features the compilation of series of increasingly more specific and informative maps and graphs regarding the avalanche hazard: terrain types, snow cover depth and seasonal extent, duration of snow cover and its elevational zonation, snow as a factor in avalanche formation, and summary map of avalanche hazard. Translated by Elliott B. Urdang, Providence, RI 02906 from: Materialy glyatsiologicheskikh issledovaniy, 1991, No. 71, pp. 86–93.     

Geostatistical incorporation of spatial coordinates into supervised classification of hyperspectral data

 This paper presents a methodology to incorporate both hyperspectral properties and spatial coordinates of pixels in maximum likelihood classification. Indicator kriging of ground data is used to estimate, for each pixel, the prior probabilities of occurrence of classes which are then combined with spectral-based probabilities within a Bayesian framework. In the case study (mapping of in-stream habitats), accounting for spatial coordinates increases the overall producer's accuracy from 85.8% to 93.8%, while the Kappa statistic rises from 0.74 to 0.88. Best results are obtained using only indicator kriging-based probabilities, with a stunning overall accuracy of 97.2%. Significant improvements are observed for environmentally important units, such as pools (Kappa: 0.17 to 0.74) and eddy drop zones (Kappa: 0.65 to 0.87). The lack of benefit of using hyperspectral information in the present study can be explained by the dense network of ground observations and the high spatial continuity of field classification which might be spurious. Received: 12 April 2001 / Accepted: 7 September 2001     

Soil erosion assessment and mapping of the algar river watershed (uttar pradesh) using remote sensing technique

This study was undertaken to prepare an inventory on soil erosion of a hilly river watershed — the Aglar watershed, part of Tehri Garhwal and Dehradun districts (U.P.), using terrain physiography and soil survey data obtained from interpretation and analysis of Landsat TM FCC (1:62,500 scale) and limited ground investigations. The watershed is divided into four broad physiographic units viz. higher Himalayas (> 2000m elevation); lower Himalayas (< 2000m elevation); river terraces and flood plains. Each physiographic unit has been further divided into subunits on the basis of aspects and landuse. Three major orders of soils viz. Inceptisols, Mollisols and Entisols were found in different physiographic units. Soil, and land properties of soilscape units viz. soil depth, texture, structure, slope, landuse and soil temperature regime were evaluated for soil-erosion hazard. The results indicate that in the whole watershed 19.13%, 45.68%, 26.51% and 7.92% areas have been found to be under none to slight, moderate, severe and very severe soil erosion hazard categories, respectively.     

Estimation and validation of snow surface temperature using modis data for snow-avalanche studies in NW-Himalaya

Snow avalanche studies require different snow-meteorological parameters for avalanche forecasting. Snow surface temperature is one of the major parameters, which is responsible for the evolution of snow pack characteristics. In the present paper, the snow surface temperature was estimated using TERRA satellite based — Moderate resolution imaging spectroradiometer (MODIS) sensor for NW-Himalayas. Ground data observed by automatic weather stations (AWS) was used to calibrate the brightness temperature obtained by MODIS thermal bands data into the actual snow surface temperature data through regression analysis. A split window technique has been implemented for the estimation of snow surface temperature. The multi-date satellite derived snow surface temperature was validated with ground data of winter 2004–05 and 2005–06 collected at various observation stations located in different ranges of NW-Himalaya. Good correlations were observed for Upper Himalaya (0.98, 0.98), Middle Himalaya (0.92, 0.96) and Lower Himalaya (0.88, 0.82) for 2004–05 and 2005–06 winter respectively. Further, estimated snow surface temperature was also verified with snow-cover information collected by manned observatories and area delineated by thematic maps of snow surface temperature was validated with the different snow climatic zones of NW-Himalaya.     

Assessment of groundwater potential zones using GIS technique

A case study was conducted to find out the groundwater potential zones in Kattakulathur block, Tamil Nadu, India with an aerial extent of 360.60 km². The thematic maps such as geology, geomorphology, soil hydrological group, land use / land cover and drainage map were prepared for the study area. The Digital Elevation Model (DEM) has been generated from the 10 m interval contour lines (which is derived from SOI, Toposheet 1:25000 scale) and obtained the slope (%) of the study area. The groundwater potential zones were obtained by overlaying all the thematic maps in terms of weighted overlay methods using the spatial analysis tool in ArcGIS 9.2. During weighted overlay analysis, the ranking has been given for each individual parameter of each thematic map and weights were assigned according to the influence such as soil −25%, geomorphology − 25%, land use/land cover −25%, slope − 15%, lineament − 5% and drainage / streams − 5% and find out the potential zones in terms of good, moderate and poor zones with the area of 49.70 km², 261.61 km² and 46.04 km² respectively. The potential zone wise study area was overlaid with village boundary map and the village wise groundwater potential zones with three categories such as good, moderate and poor zones were obtained. This GIS based output result was validated by conducting field survey by randomly selecting wells in different villages using GPS instruments. The coordinates of each well location were obtained by GPS and plotted in the GIS platform and it was clearly shown that the well coordinates were exactly seated with the classified zones.     

A method for groundwater prospect zonation in data poor areas using remote sensing and GIS: a case study in Kalikavu Panchayath of Malappuram district,Kerala, India

Abstract

The present study was an attempt to delineate potential groundwater zones in Kalikavu Panchayat of Malappuram district, Kerala, India. The geo-spatial database on geomorphology, landuse, geology, slope and drainage network was generated in a geographic information system (GIS) environment from satellite data, Survey of India topographic sheets and field observations. To understand the movement and occurrence of groundwater, the geology, geomorphology, structural set-up and recharging conditions have to be well understood. In the present study, the potential recharge areas are delineated in terms of geology, geomorphology, land use, slope, drainage pattern, etc. Various thematic data generated were integrated using a heuristic method in the GIS domain to generate maps showing potential groundwater zones. The composite output map scores were reclassified into different zones using a decision rule. The final output map shows different zones of groundwater prospect, viz., very good (15.57% of the area), good (43.74%), moderate (28.38%) and poor (12.31%). Geomorphic units such as valley plains, valley fills and alluvial terraces were identified as good to excellent prospect zones, while the gently sloping lateritic uplands were identified as good to moderate zones. Steeply sloping hilly terrains underlain by hard rocks were identified as poor groundwater prospect zones.     

Fuzzy–frequency ratio model for avalanche susceptibility mapping

Avalanche activities in the Indian Himalaya cause the majority of fatalities and responsible for heavy damage to the property. Avalanche susceptibility maps assist decision-makers and planners to execute suitable measures to reduce the avalanche risk. In the present study, a probabilistic data-driven geospatial fuzzy–frequency ratio (fuzzy–FR) model is proposed and developed for avalanche susceptibility mapping, especially for the large undocumented region. The fuzzy–FR model for avalanche susceptibility mapping is initially developed and applied for Lahaul-Spiti region. The fuzzy–FR model utilized the six avalanche occurrence factors (i.e. slope, aspect, curvature, elevation, terrain roughness and vegetation cover) and one referent avalanche inventory map to generate the avalanche susceptibility map. Amongst 292 documented avalanche locations from the avalanche inventory map, 233 (80%) were used for training the model and remaining 59 (20%) were used for validation of the map. The avalanche susceptibility map is validated by calculating the area under the receiver operating characteristic curve (ROC-AUC) technique. For validation of the results using ROC-AUC technique, the success rate and prediction rate were calculated. The values of success rate and prediction rate were 94.07% and 91.76%, respectively. The validation of results using ROC-AUC indicated the fuzzy–FR model is appropriate for avalanche susceptibility mapping.     

Remote sensing techniques to locate ground water potential zones in upper Urmil River Basin, district Chhatarpur — Central India

In the present study efforts have been made to locate favourable zones for ground water targeting using IRS-USS-II data, Hydromorphogeological lineament, lineament density and ground water prospect maps have been prepared through visual interpretation of geocoded images on 1:50,000 scale and Survey of India topographical maps of the same scale. The resulting base line information has been integrated for evaluating ground water potential of mapping units. The alluvial plain, flood plain, infilled valley and deeply buried pediplain ace the prospective zones of ground water exploration and development. Fractures and faults parallel to drainage courses constitute priority zones for ground water targetting.     

城市开发区土地集约利用评价——以武汉市为例

针对城市开发区土地集约利用低、不能充分发挥其经济效益、社会效益和环境效益等问题,对各开发区进行了熵权模糊综合评价。本文以武汉市的16个开发区为研究对象,研究选取了重要程度较高,能客观反映开发区状况的10项指标,并利用熵权法对指标赋予权重;根据模糊变换原理及最大隶属度原则,构建了模糊综合评价模型;使用Python构建模糊计算流程脚本,输入权重及各指标值,计算武汉市16个开发区的结果向量,并利用最大隶属度原则确定了其对应的土地集约利用程度,从而得出武汉市16个开发区中处于集约开发利用的有4个,处于适度开发利用的有2个,处于过度开发利用的有1个,其余的9个均为轻度开发利用。采用ArcGIS查询统计和Voronoi图的C_V值对4个集约利用的开发区进行分析,分析了这4个开发区企业、行政村、学校、医疗机构、基础服务设施的分布与利用状态。本文采用的土地集约利用评价方法具有较高的适用性,可为土地集约利用程度的提升提供现实依据。     

Seismic hazard maps of Yangon and its surrounding areas

The purpose of this study is to develop probabilistic seismic hazard maps for Yangon and its surrounding areas including ‘Peak Ground Acceleration’ values for 2% and 10 % probability of the exceedance in 50 years at rock sites. The present study area is situated between the latitudes of N 13°37′ and N 20°2′ and the longitudes of E 93°35′ and E 99°5′. The study areas are focused on nine source zones centered around Yangon with the radius of about 200 km. The probabilistic seismic hazard maps are created by ArcGIS-9.3 software.     

Groundwater prospects evaluation-based on hydrogeomorphological mapping: A case study in Kancheepuram district,Tamil Nadu

Water is the most important natural resource which forms the core of the ecological system. The advent of remote sensing has opened up new vistas in groundwater prospect evaluation, exploration and management. The role of hydrogeomorphological units in tile storage of groundwater from the Kancheepuram distict has been investigated using IRS P6 LISS-III data. The Kancheepuram district exhibits diverse hydrogeomorphological conditions where the groundwater regime is controlled mainly by topography and geology. The extent of various water prospectus zones in terms of percentage includes, maximum area, particularly the north-western, and central part which is characterized by good potential occupying about 43% of total area. The moderate potential is marked by only 35%, and is scattered along the northern and southern side of the study area, the remaining 12% is of poor prospectus, which is falling in the coastal region of the study area.     

Mapping of soil degradation hazards by remote sensing in Hanumangarh district (western Rajasthan)

In the present study, efforts have been made to identify and map areas affected by various soil degradation processes in Hanumangarh district of western Rajasthan. Soil degradation processes were identified by using IRS-1B satellite image of the year 1998, SOI toposheets, ground truth verification and soil studies. The kind, extent and degree of soil degradation have been mapped in an area of 9703 km². The study reveals that the soil degradation problems were mainly due to wind erosion/deposition and water-logging, followed by salinity/alkalinity, water erosion and wind and water erosion combinedly. Nearly 38.7% area is subjected to slight and moderate degradation, which can easily be combated by adopting the suggested techniques and 17.1% area is free of hazard. Soil degradation processes have resulted in the loss of organic carbon, available Phosphorus and Potassium. Soil degradation due to water logging/salinization has also shown a significant increase in electrical conductivity and available potassium content of soil.     

应用卫星与气象数据及其关系研究黄河流域的荒漠化现状

本文应用20年（1981—2000年）的卫星数据反演归一化差值植被指数（NDVI）,同时获取地面格网的温度与降雨数据,并分析这些数据之间的关系。基于地面的温度和降雨格网数据将研究区划分为8个气候区域,再利用NDVI数据把降雨量最少的3个气候区——区1,2,3各划分为10个等级。此外,分析这3个气候区在1983—1998年15年间的NDVI变化状况,结果显示出研究区荒漠化状况的加剧。     

Assessment of soil degradation Hazards in Jalor and Ahor Tehsil of Jalor district (Western Rajasthan) by remote sensing

In the present study efforts have been made to identify and map areas affected by various land degradation processes with the aid of Landsat TM imagery data of 1988 and ground truth verification. The kind, extent and degree of land degradation have been mapped. In an area of over 4,124 sq. km. 51% was affected by water erosion and 30% area by wind erosion. Nearly 1.14% area is affected by salinity. Degradation due to combined effect of water and wind erosion and water erosion and salinization has affected 8.20% of the study area. 1.53% area is free from any hazard. Remaining 7.85% area comes under hills and rivers. Nearly 44 percent of the affected area is subjected to moderate and severe degradation which can easily be combatted by techniques referred.