Integration of Remote Sensing Data With GIS Technology

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    Integration of Remote Sensing Data With GIS Technology for the Acceleration of

    the Activities in National Mapping Agencies

    Abstract

    As the world changes more rapidly, the demand for upto-date information for resource

    management, environment monitoring, planning are increasing exponentially. Mapping

    agencies must respond to the concerns of the public, and do so with increasing

    efficiency and effectiveness. Integration of Remote Sensing with GIS technology will

    significantly promoted the ability for addressing these concerns.

    Despite a decade of effort to active completely automated integration process, authors

    identify a conceptual model that permits utilization of computers with Remote Sensing

    and GIS technology with human contextual analysis in order to support the National

    Mapping Agencies to acceleration their activities.

    Introduction

    The well-worn argument that geo-information is a pre-requisite for" development. Most

    map makers absolve themselves from responsibility for c) "' the poor state of mapping

    with their territory. As the mapping will take several years to complete, it is clear that the

    National Survey and Mapping organization has to take initiatives to supply upto date

    geo- information for the users on their various requirements and expectations.

    The integration of satellite data into a Geographic Information System (GIS) is one of

    the great idea that focus on the rapid acceptance of GIS technology in to the geo-

    information oriented applications in operational environments. Institutionalizing of the

    GIS and Remote Sensing process into everyday decision making has greater efficiency

    to overcome the problems identified in mapping at a National Mapping agency.

    Hence, authors identified key issues of integration of Remote Sensing with GIS and the

    proposed structure perhaps most significant, however, is that the integrated approach

    leads to a new view of supplying geo- information rather than being static documents to

    completely recreated at periodic intervals.

    Integration Of Remote Sensing With GIS

    The volume of Remote Sensing is so large, its associated powerful image processing

    technology is used to manage geo-information with preprocessing analysis, accuracy

    assessment and information distribution.

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    GIS are more and more being used for the storage and analysis of geo- referenced data

    and also it handles the linkages between spatial entities and their discrete attributes.

    GIS system have become accepted as a standard way of handling geographic data and

    performing analysis on those data for a number of earth related disciplines-

    With the availability of high resolution satellite data and its processing technologies.

    integration of digital image analyzing systems with advance GIS systems permit

    compositing data sources as well as promoting a partnership between man and

    machine. Furthermore. a GIS when combine with upto date remote sensing data could

    assist in the automated interpretation. change detection and map revision processes.

    Satellite : data offer repetitive. synoptic and accurate information of the earth's r surface

    and as such offer the potential to monitor the dynamic changes F' with GIS.

    However. one should bear in mind the integration will largely depend on the ability to

    understand and conceptualize the transition between one representation to another.

    Technical Impediments to Integration

    Geographic phenomena do not occur with a specific data structure. Obviously certain

    types of objects are well represented in a raster data structure (eg.. elevation. soil type)

    while others more appropriately represented as vectors (eg. .boundaries. point

    information) . .'f Consequently. it can be significant strength for a GIS to incorporate

    advantages 0: both data types. New commercial systems designed expressly around

    data 1ntegrat10n are also emerged. However, the full potential of integrate GIS with

    remote sensing will not be realized unless we overcome the dichotomy of data

    structures for GIS and remote sensing (Ehlers, 1991) .Data accuracy and systemcommunications are other major issues that discussed under problems related in

    integration.

    Data Structures

    The major problem is caused by the different in the structures used to acquire and store

    data. Remote Sensing detectors produce raster digital information directly then the

    raster processing of these data seems 'natural" .GIS systems typically used the vector

    data structure.

    In a model of geo-information extraction from raster imagery, at lower level processed

    raster data can be used to extract and manipulate at ".."",,-, pattern recognition in

    middle level. At the highest level with the knowledge based information. models the

    predictive description of the "imaged" object. Hence. at the middle and the highest level

    the image information can be stored as vectors or ojects than gray values. thus ,f;;

    fac1l1tat1ng the 1ntegrat10n approach. Add1tionally. the data structures that used for

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    computer vision, quad trees and other tessellation are also possible data structures to

    manipulate remote sensing data (Samet.,1984).

    Presently, the common used approach dealing with this problem is data conversion

    eventhough the raster to vector conversion leads to a loss of accuracy of information.

    Data Accuracy

    The classification accuracy, mapping accuracy and spatial resolution are main data

    accuracy problem which have to considered when integrating Remote Sensing data

    with GIS. The problem of classification accuracy present a major difficulty in the

    integration. Researchers has been suggested to improve Remote Sensing image

    classification accuracy by referencing the information already available in GIS's.

    A data processing system must assess levels of data accuracy and associate the level

    with the data it provides. Based on the assessment a user can understand how reliablethe data are and determine how being to use them.

    Different methods are used in Remote Sensing and GIS's for data accuracy

    assessment. The method are incompatible with each other. Remote Sensing data

    analyzing mainly uses the error matrix method which provide global accuracy

    information while GIS operators use error model which provide more local accuracy

    information. But up to now no effective approach has been reported which facilitate the

    flow of accuracy information between Remote Sensing image analysis system and

    GIS's (Fangin Wang., 1991).

    System Communication

    In the communication between Remote Sensing system and GIS, spatial and non

    spatial data must be transferred in an integration fashion. Facilitating the communication

    have been mainly made on query/reasoning languages and communication procedures.

    This method developed usually include the steps of language conversion, query

    optimization and data translation. Even so mismatch is unavoidable and the

    communication is still expensive (Fangin Wang, 1991).

    Poster Session 3

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    Integration of Remote Sensing Data With GIS Technology for the Acceleration ofthe Activities in National Mapping Agencies

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    Issue of New Integrated GIS DesignIn the technological and institutional side, potential and problems have been mentioned. The proposedstructure (figure 1.0) is to accelerate the activities in a national mapping agencies and this integratedapproach permits exploitation of multiple data sources and provides accelerated mapping capabilities.

    Figure 1.0: Integrated GIS System

    It is possible to input vector data as well as raster format data to above proposed integrated data basemodel.

    Existing analogue form maps can be convert to digital form by manual digitizing or scanning. The digitalphotogrammetric and digital form field survey data can connected to the databases directly. In this caseuser can get digital form map as well as analogue form maps. The advantage of use of Remote Sensing

    data is updating all topographic maps and thematic maps within a short time period. Hence, alwayspossible to supply correct information to user. Further more, this data base can provide not only mapinformation but also statistics and reports.

    Since the capability thus exist to implementation the proposed structure, Survey and Mappingorganizations should examine the major obstacles which have been encountered to date. The impact ofautomationon the need of software system architecture, hardware system .architecture and educationand training to be recognized.

    Software System ArchitectureSoftware system architecture means this "Organizational Context" within .which all the softwaremodules, programs etc. perform certain tasks and communicate with each other and data stores. Itreflects the processes r or group of processes defined in the logical architecture.

    The software should be selected which has capability for data capture by manual digitizing or scanning,Remote Sensing data on tape and digital form field survey data. Attribute data should be able to enterfrom alpha-numeric terminals.

    Database management system interface should be capable of providing search/query facility to accessgraphical display from the database to , satisfy a certain search criteria to display certain map elementsand also in the opposite direction to access the database from graphical display to textural attributeinformation about certain map elements and generate a report about them. Also it should havepossibility for editing and utility programs to improve the quality of graphical data. Specially there should

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    be image processing system to process and class1fy Remote Sens1ng data.

    Software system should be able to give out put in paper plot either as verification plot to check the dataquality or precision final plots from graphical out put and attribute data in report form. Also it should bepossible to out put digital map sheet on tape as back-up tapes.

    Hardware System ArchitectureThe hardware system should be chosen to match the system capability requirements to perform thetask imposed by the logical model and the performance requirements necessary for the softwaresystem capabilities.

    Education and TrainingTo implement the database model have to give training to persons with necessary and innovative skillsto manage the transition from existing analogue to digital technologies and to decide how conventionaland new processes can best be integrated to optimally serve user needs.

    ConclusionIntegration of Remote Sensing and GIS technologies will significantly promoted the ability to handlegeo-information. It is possible to obtain 1 high benefits in producing and updating maps with proposedsystem. It has facilities to do repetitive task without complaining, sort things fast, draw and store points,lines or area fastly and retrieving of geo- information rapidly. Thus the new system leads to geo-information which, are accurate and reliable in rather short time for decision making.

    But some times it takes the same time to do a job the first time whether using a computer or by hand.The difference is on the second or third time around, repeating the process with only a few changes tomake anew map.

    References

    Fangju Wang, 00 Integrating GIS's and Remote Sensing Image Analysis Systems by UnifyingKnowledge Representation Schemes", IEEE Transactions on Geo Science and RemoteSensing, 1991.

    Manfred Ehlers, "Remote Sensing and Geo Information Systems : Towards Integrated SpatialInformation Processing", IEEE Transactions on Geo Science and Remote Sensing, 1990.

    Manfred Ehlers, Geoffry Edwards, Yvan Bedard,"Integration of Remote Sensing withGeographic Information System: A necessary evolution", International Journal ofPhotogrammetry and Remote Sensing, 1990.

    John Leatheradle,"New Strategies for Funding Mapping and Land Information System",Conference of Common Wealth Surveyors, 1991.

    Samet H.,"The Quad tree and Related Hierarchical Data Structures", ACM Comput. Surveys,vol.16, 1984.