On the oscillation of Balat river,district Khasi and Garo Hills,Meghalaya

Balat River has abandoned its westerly course and followed an old course to the east during the recent past. This has lead to the recognition of an oscillation pattern for this river with its periodic shift where the course if confined to the zone bounded by the two channel courses.     

Economic, legal, and public policy issues influencing the creation, accessibility, and use of GIS databases

Rhind (1992) argued that government data policies and Intellectual Property Righr (IPR) considerations would play an increasingly large role in influencing the use of GIS. This has proved to be correct in general but the non-technical factors affecting data collection, supply, and price have become ever more complex. Indeed, one characteristic of the present situation is that it is now impossible to consider the legal, economic, and public policy issues in isolation. Consequently, this paper sets out to identify the interactions between them and the areas of conflict. It draws upon the literature of a much wider area than traditional GIS. This approach is essential because of two factors. The first is that GIS databases are presently of modest commercial value compared to some other data and hence key decisions on IPR, etc are being made outside our discipline. The second is that the nature of GIS databases is mutating rapidly through the wider use of multi-media and of the internet. It is concluded that the future is largely unpredictable in any detail since the interactions differ in different countries and at different moments in time. In many cases, however, revenue generation from sales or leasing of data or from services built upon data exploitation is likely to be a characteristic of both the public and the private sectors. Such charging has observable beneficial effects to set against the frequently claimed disadvantages, whether measured in financial, legal, or public access terms.     

Effects of Land Transformation on Water Quality of Dal Lake,Srinagar, India

The present study focuses on the growing human needs which drive the native boatmen of the Kashmir valley (Hanjis) that bring the interchanges of land use/cover classes in Dal lake and its environs of Srinagar city. Further to assesses the effects of land transformation on lake water quality. The results suggested that the significant land use changes have been occurred during the past of 30 years (1981–2011). Besides this, interchange of land has taken place between different land uses classes, which has resulted into lake water pollution due the addition of various nutrients/pollutant discharged from Hanjis activities. The study concludes that the land transformation has converted the once fresh water lake much deteriorated pond.     

Galileo status: orbits,clocks, and positioning

The European Global Navigation Satellite System Galileo is close to declaration of initial services. The current constellation comprises a total of 12 active satellites, four of them belonging to the first generation of In-Orbit Validation satellites, while the other eight are Full Operational Capability (FOC) satellites. Although the first pair of FOC satellites suffered from a launch anomaly resulting in an elliptical orbit, these satellites can be used for scientific applications without relevant limitations. The quality of broadcast orbits and clocks has significantly improved since the beginning of routine transmissions and has reached a signal-in-space range error of 30 cm. Precise orbit products generated by the scientific community achieve an accuracy of about 5 cm if appropriate models for the solar radiation pressure are applied. The latter is also important for an assessment of the clock stability as orbit errors are mapped to the apparent clock. Dual-frequency single point positioning with broadcast orbits and clocks of nine Galileo satellites that have so far been declared healthy already enables an accuracy at a few meters. Galileo-only precise point positioning approaches a precision of 2 cm in static mode using daily solutions.     

Mapping and monitoring of Rann (tidal) ingress in Banni Plains,Kachchh, Gujarat using multi-temporal satellite data

The Rann ingress into the ‘Banni Plains’ of Kachchh district, Gujarat which is famous for the sprawling grasslands supporting significant cattle population is taking place at an alarming rate. This has resulted in the desertion of many villages due to intrusion of Rann waters. In the present investigation multi-date satellite data has been analysed to map and monitor the Rann ingress during the period 1975 to 1989. Detailed analysis has brought out that the inundation is quite rapid affecting about 244 sq. km area during 1960–1989 period. Mapping of the creeks has also been done to understand the possible mechanism of ‘Rann ingress’.     

Assessment of coastal bio-resources of the Palk Bay,India, using IRS-LISS-III data

Coastal resources viz., coral reefs, seagrasses, mangroves, and coastal land features viz., sandy beach, mudflats and salt pan/aquaculture ponds were classified and assessed in the Palk Bay region of the south-east coast of India using IRS LISS III satellite image (1996, 2000, 2002 and 2004). The study recorded an areal coverage of 286.95 ha of reef area during 2004, which is 177.54 ha lesser than that of the reef area of 1996. The reef vegetation composed mainly of seaweeds has gained over 29.44 ha during the same period. Likewise, sand over reef area has also increased alarmingly i.e. 120.34 ha between 1996 and 2004. The seagrass beds of Munaikkadu region of the Palk Bay are comparatively protected and have gained over 7.5 ha between 1996 and 2004. It has been found that both the dense (2.99 ha) and sparse (36.45 ha) mangroves have gained their areal coverage considerably between 1996 and 2004. Whereas in Devipattinam region, many anthropogenic pressures are exerted only on the seagrass resources which has led to the reduction of over 785.5 ha of dense seagrass beds between 1996 and 2004. The study clearly indicated that the resources are under the pressures of low to high threats, especially the coral reefs and seagrasses, if the pressures continue, coastal resources of the Palk Bay may face serious threats of destruction in this part of the Bay in the years to come.     

Qibla,and Related,Map Projections

The qibla problem—determination of the direction to Mecca—has given rise to retro-azimuthal map projections, an interesting, albeit unusual and little known, class of map projections. Principal contributors to this subject were Craig and Hammer, both writing in 1910. A property of retro-azimuthal projections is that the parallels are bent downwards towards the equator. The resulting maps, when extended to the entire world, thus must overlap themselves. An unusual recent discovery from Iran suggests that Muslims might have been prior inventors of a similar projection, by at least several centuries. A later corollary by Schoy leads to a new "cylindrical" azimuthal map projection with parallels bending away from the equator, here illustrated for the first time.     

GIS, expert systems, and interoperability

Integrating a GIS has been a common way to combine the functionality of two or more systems for some time. A three-dimensional model of integration is described which shows the range of linkages that can be achieved. Extremely flexible and dynamic linkages between systems can now be created through the recent advances of client/server and object-oriented technology. An expert system shell is coupled with a GIS to create a generic spatial rule-based toolbox called SES (spatial expert shell). An expert system developer using this toolbox can transparently access spatial data and relationships from a GIS by linking application objects to spatial classes. These spatial classes include methods that format and send requests to the GIS server. Thus the linkage is determined at run-time allowing a flexible interwoven interaction between the expert system and the GIS.     

Landuse map of jharia coalfield,eastern india,aided by remote sensing

Land use conditions are bound to change in any area where some amount of mining activity is going on every day. For such a field, a land use map of existing conditions helps much in monitoring the damages to land use caused by mining, if the pre-mining land use conditions are known. Further, such maps help in formulating the final land use plan, as an input information about capability of each and every parcel of land in that field. With this view, a land use map of Jharia coalfield for 1987 has been prepared using satellite imagery data. This has helped much by saving time and giving an overall picture of land use pattern of the entire coalfield.     

Geological, geomorphological, hydrogeological and land use/land cover studies around kamthi area, Nagpur district, Maharashtra using remote sensing techniques

Detailed geological, geomorphological, hydrogeological and land use/land cover studies have been carried out for the Kamthi and adjoining areas of district Nagpur by visual interpretation method of remote sensing data of IRS LISS III, FCC of bands 2, 3 and 4. The interpreted data is supplemented as well as cross-checked by field visits to add minor details of lithounits, nature of lithological contacts, geological and geomorphological features. On the basis of these studies, the various lithounits: Archaean metasediments, the Talchir Shale. the Barakar Sandstone, the Kamthi Sandstone, basalt and alluvium have been mapped. Geomorphological units are mainly of denudational and fluvial origins and are represented by dissected plateaus, pediplains, pediments and alluvium. The land use/land cover study shows that a major part of the area is covered by agricultural land followed by built up and waste land. The flowing and stagnant water bodies, mine and mine dump have also been identified. In the present paper, an attempt has been made to delineate the area with reference to ground water prospects into excellent, very good to good, moderate and poor ground water prospect zones. It has been observed that the sandstone lithounits form excellent aquifers while the basalt and shale form moderate to poor aquifers respectively.     

Design and Implementation of a Model,Web-based,GIS-Enabled Cancer Atlas

Abstract

The design and development of a highly interactive web-based, GIS-enabled atlas is reported. The atlas is a prototype, designed as a model for implementation of atlases to support government cancer-control activities. This model integrates symbolisation and design principles from print cartography, interaction strategies from exploratory geovisualisation, and web-map/web-feature service advances from GIS. The atlas has been implemented using a client-server architecture. It makes use of two open-source GIS tools, PostGIS (as the system database) and GeoServer (to connect the database to the client mapping application). The client mapping application has been built in Macromedia Flash. The entire client-server architecture is described, then direct primary emphasis is focused on the client mapping application. For this component of the system, the interface design strategy is detailed, the approach taken to implement this strategy in Flash is documented, and the mechanisms developed to build dynamic links from the client to the underlying database through the server are outlined. Features of the atlas are presented through a prototypical use scenario for a target user.     

GIS and simple systems for visual,interactive, spatial analysis

Abstract

In much the same way as a spreadsheet is more appropriate to some needs than a fully relational DBMS, many users interested in analysis of spatially referenced data have fairly unsophisticated requirements for extensive data storage or complex retrieval functions, and limited needs for topographic detail, cartographic accuracy or advanced map editing; however, they do require access to a wide range of statistical functions for data transformation, reduction and smoothing, multivariate analysis, and the modelling of spatial relationships. This paper argues that the needs of such users are poorly met by the 'mainstream' model for GIS that is often presented in the literature. A PC-based system, equivalent in GIS terms to the spreadsheet, is described. It integrates simple data structures, limited map creation and editing, a powerful range of standard and spatially orientated statistical functions, and the ability to interactively present results through chloropleth, contour, proportionate symbol, or proximally shaded maps. It is particularly designed to be easily accessible and to encourage visual interactive analysis. For some users such a system has acted as an adequate solution in its own right and for others it has provided a useful educational transition to more extensive and powerful systems.     

中国西部喀喇昆仓明铁盖多金属矿化区的卫星遥感勘查

成矿环境的地质分析与遥感探测标志是矿产遥感定位的     

网络文本数据时空感知计算概念、方法及应用场景

网络文本数据作为网络传感数据的一种,因其包含大量的时空信息,以及丰富的语义信息,不仅能够用于研究社会问题的时空特征,也能够对社会现象的时空规律提供语义上的可解释性,因此存在一定的应用价值,目前已逐渐得到研究者的关注。本文提出了网络文本数据的一般概念表示,分析了网络文本数据的类型和特征,重点梳理了网络文本数据时空感知计算的计算方法,总结了文本优先+地理背景和地理优先+文本增强两种计算模式,并从静态到动态、场景到区域的视角总结了4个相关应用场景。     

Statistical, Structural, Hybrid, and Graph Theoretical Features to Measure Land Development

Extracting information on a developing region from its sequential satellite images has many benefits. Therefore, in a previous study, we introduced graph theoretical and conditional statistical features to measure land development in a predefined region. There, we only used the grayscale information from the satellite image at hand. Here, we extend that work by introducing novel statistical, hybrid, and graph theoretical features using multispectral information. We also introduce novel structural features based on three different structure extraction methods. We test our new features on a diverse data set and report their performances in measuring land development.     

我国地图学的过去、现在与未来

作者从事地图学教育与科研40余年,本文对我国地图学作了回顾和若干思考,简要地阐述了地图学的历史发展和主要特点以及现代地图学的成就,最后提出地图学未来发展的几个重要问题。     

Long-term thinning of the southeast Greenland ice sheet from Seasat, Geosat, and GFO Satellite Radar altimetry

Geosat Follow On (GFO) radar altimeter data are processed with previous altimeter datasets to measure long-term elevation change of higher elevation portions of the southern Greenland ice sheet over time periods from 1978-1988, 1985-2002, and 1978-2002. Average elevation change results indicate approximately zero overall elevation change for all time periods. The results also indicate that upper-elevation thinning in southeast Greenland has been widespread and has existed for several decades.     

福建省上杭紫金山铜金矿床遥感地质解译及找矿效果

本文主要介绍用TM图像为主的遥感资料,在福建省上杭紫金山铜金矿床及其外围地区进行地质解译所获得的成果,并简介了已知矿床的“线、环、色”遥感地质模型,评价了矿床外围的成矿地质条件,圈定了12个远景区。近二年来,地质队在所圈定的远景区内找到很有希望的铜（钼）矿（化）多处。     

LEO Enhanced Global Navigation Satellite System (LeGNSS):progress,opportunities, and challenges

With the completion of Chinese BeiDou Navigation Satellite System (BDS), the world has begun to enjoy the Positioning, Navigation, and Timing (PNT) services of ...