Mahmoud AL-Hader
[email protected]
Ahamd Rodzi, Abdul Rashid Shariff
GEOMATEC
Bahrain Center for Studies and Research
Bahrain
1. Introduction
This paper discusses new techniques using web services to provide a kind of channel among real estate data, real estate features.
Blurb:
Spatial web services facilitate integration of property data with GIS a server ArcIMS web server can be applied in data uploading to the GIS server Use of 3-D will enhance the visual capabilities for the real estate
Paper:
Spatial web services will facilitate real estate agents to integrate property data that is related to property location with GIS a server through the web (see Figure 2), according to proposed framework, two functions are to be provided, the first function is for integrating GIS server with the data available with the realtors that allow them to upload property coordinates, either property is land (without address assigned), or constructed property (address assigned to it) like home, villa, realtors need to upload the address of constructed properties, and beacon coordinates of the land, then web service will take care of the creating the geometric feature representation (i.e. geocoding, address matching). The second function to be provided is pertaining to requesting mapping report, therefore, a technology is required for allowing realtors to request sort of map report, needs specifying certain parameters related to the map in particular (i.e. map extent, scale, type and format) or based on the address if available.
Web services are a proper solution for the integration among distinct systems, specially, the debatable systems in terms of format and platform. Accordingly the new trend of the system integration currently through web, Extensible Markup Language (XML) is the best solution to develop a technology to interface both real estate properties and digital mapping system, on the other hand both systems have potential relationship with ground (geographical presentation) thus web service can be called as spatial web service.
The Framework
Recently, private or government establishments started recognizing the significance of generalizing and centralizing the databases in all information formats available (i.e. descriptive and spatial), it is known that the mount of usability and utility when using proper integrated Central Information System (CIO) that comprises all data from responsible agencies at the same place using proper updating strategy, at a periodic basis and hosting it using one framework of servers. This kind of systems form management point of view can not be done unless, government adopt the system in terms of servers and data integrity by providing rules to maintain it. Figure 1 describes the proposed algorithm to collect and analysis the layers required, to make the spatial web service up and running.
Government needs to establish a kind of corporation with all in charge agencies, to collect all essential data layers required for mobilizing spatial web service; The essential layers required are listed below:
1: Administrative datasets: Administrative datasets are comprised of different data layers, Area names, Block, Coastline, Governorate, Ground Control Points, and International Boundary. Block dataset represents the smallest Administrative Sub-divisions, also know as census block. The main purpose of this data is to demarcate boundaries for managing all other geospatial information’s such as roads, address etc.
2: Building foot prints: Buildings data corresponds to the building footprints with its height; height information has been collected by using GPS and Ortho-photo. The purpose of Building data is to provide a valuable source of information visibility analysis, zoning rule violation studies, precise dimensions of buildings and related attributes.
3: Building address: Address data refers to official building address as per National Address Database (NAD) of CIO (Central Information Organization). Address data is available as point data and address range in roads data as well.
4: Road Networks with proper classification: Roads centre line database is a highly detailed road network database compliant to GDF (Geographic Data Format) standards. This data developed to provide up-to-date road network information for use with web services, location-allocation analysis and other spatial analysis.
5: Place of Interest (POI): It is a collection of places of interests categorized into types and subtypes like primary schools, boy schools. etc. This data provides actual location of places of public and business interests. The purpose of the POI database has been created to provide up-to-date locational and attributes information for public to locate POI of interest and for performing spatial search and analysis,
These essential data layers will be used as a base map for creating the ArcIMS web service to provider output map report as illustrated in Fig.1. Therefore the proposed spatial web service will provide two main functions as mentioned above for both uploading as well as requesting data.
Figure 1 framework in providing spatial web service
Procedure For providing spatial web service
Two functions are going to be integrated for providing spatial web service, Figure 2 explains the schema for uploading property data, beacons coordinates are required to generate plot polygon by using VBScript and ArcIMS object model platform, the uploaded coordinates must be according to local coordinate system (datum/projection system) defined in GIS data layers hosted in CIO servers.
The constructed properties having addresses (i.e. home, villa, apartment), web service will upload address of the building to match it with original address layer located in GIS server (where the data hosted), two possibilities are there, address matched (which is the majority) because all constructed buildings have to follow roles applied in the CIO in terms of assigning address to each building before connecting any utility services (electricity, water, communication, sewerage). In case address is not matched or the coordinates are not available for certain reasons, the map based search is used to locate the property tentatively like a point in the middle of the property, to simplify locating property location. Search engine should be developed to allow realtors to specify the location either search by block or by area name, whichever available, see Figure 2 for clear illustration.
Figure 2 Procedure of providing spatial web service
Procedure of collecting and preparing GIS data
Preparing and collecting GIS data layers is the responsibility of government, data is the critical path in this kind of applications that are developed based on the data usability. Since the data is the most expensive and time consuming, GIS applications, government should host both, server applications and all developed Internet mapping services (i.e. ArcIMS services and all related systems).
ESRI GIS data structure is used to facilitate mapping side and to enhance the performance for both updating and requesting mapping reports as well, Figure 3 shows the procedure of data collection and consolidation between distinct governmental establishments. Figure 3 also offers a procedure for data management and sorting as well in the GIS server.
Figure 3 Procedure of collecting and preparing GIS data layers Implementation of a web service for real estates is illustrated in Figure 3. The property details that needs to be updated has to be in one out of two data formats, either as a beacon coordinates for lands or as and address for constructed properties such a villa. Therefore, the realtor has to use spatial web service to upload property locational parameters. ArcIMS 9 Architecture and Functionality (2004) presenting the role of ArcIMS web server can be applied in data uploading to the GIS server. The updated GIS data will be available for requesting maps and reports.
Figure 3 Procedure of collecting and preparing GIS data layers
web service architecture
Web service architecture is the logical evolution of object-oriented analysis and design, web services are stable to do program to- program interactions. Web services allow companies to reduce the cost of doing e-business, to deploy solutions faster, and to open up new opportunities. Fundamental concepts in web services are encapsulation, message passing, dynamic binding, service description and querying. Sunil et al, (2004) implement the necessary activities need to be developed in any web service environment:
- Web service creation
- Web service publication on internet
- Web service for potential users to search and identify.
Once the web service created it requires three fundamental operations using WSDL and/or UDDI to be used. Publish, find, and bind. Service providers publish services to the service broker. Service requester finds the required services using a service broker and bind to them.
Figure 4 web service interface
System Requirements
The required system components for establishing spatial web services for both hardware and software, could be as standard workstation specs (Pentium 4), as shown in figure 5. The hardware specs as any work station that suitable to deal with maps, satellite imagery, programming compilation engine and able to host internet/desktop application. Regarding the software’s required to build the system, the softwares that will be required are Microsoft windows server, .Net for programming, SQL Server to manage the database and ESRI platform for creating the digital maps.
Figure 5 system requirements
Conclusions
Web services lets users freely combine services to create customized solutions with minimal programming, integration, and maintenance efforts. Such a model is the key to extending GIS beyond its traditional boundaries of mapping to embrace a broader community of users and a wider scope of services. D. Abel et al, (1998) debate the development of this kind of models that should leverage general web services technologies and extend them to address any requirements unique to the GIS data community. Using web service for integrating real estates with Geographic Information System (GIS) will demonstrate the acceptability of web service in lot of applications that have any kind of relation to the ground. In any country accordance to high priority of e-government initiatives and emphasis on enhancing service quality and competence, GIS web services are going to play an important role at every level to enable the smooth sharing of spatial information among different user organizations.
Future work
GIS web services needs continuous improvements in terms of both graphical and attribute information’s. Also, the data need to be updated and maintained using the latest technologies available to make the integration with the real estate data more reliable.
- Use of 3-D will enhance the visual capabilities for the real estate features and other land features.
- Using high resolution satellite imageries, such as Quick Bird, and IKONOS could be done easily and will add value for visualizing real estates spatially with using Zoomify and Macromedia technologies for browsing heavy images on the web.
