LSGI4321 Geospatial Data Mining and Knowledge Discovery Individual Paper Pau Siu Chung (10525309D)You are instructed by Lands Department to review their web-based GeoInfo Mapapplications. Please critically review the strength and limitations of thetechnologies employed, and suggest improvements. IntroductionGeoInfo Map is a web-based map portal developed by Land Information Centre (LIC)of the HKSAR Lands Department. It was launched and opened to the public on 26May in 2010. The main objective of this Map is providing geospatial information tothe public via the Internet effectively. It provides a common platform to deliver thegeospatial and geo-referenced information from Lands Departments, and othersgovernment bureaus and departments (SMO, 2010; ESRI China, 2010).The user can freely access the GeoInfo Map with Internet service and a modern webbrowser. The user may also click the “Link to GeoInfo Map” hyperlink on the bureau’sor department’s websites to access to the specific spatial information. The Mapallows users to pan and zoom in/out the digital map with multiple scales. At thesame time, the users can retrieve the information by searching and filtering theattributes data, or entering the coordinates directly.On the following, the technologies background and functions of the GeoInfo Map willbe introduced. Therefore, the strengths and limitations of the technologies employedwill be discussed. Finally, this essay will be concluded by discussing some feasibleimprovements and enhancement to the current system. TechnologiesTo discuss about the technologies employed in GeoInfo Map, the GeospatialInformation Hub (GIH) from Lands Department should be introduced first. In 2004,LIC established GIH via the government intranet. GIH project aims at providing aplatform to facilitate effective geospatial information exchange among the differentgovernment bureaus and departments. It improves the efficiency for the flow ofspatial data and the spatial-related collaboration.GeoInfo Map is an online GIS application which is developed based on the GIH. It can
be known as a public version of GIH. Thus, the Map inherits the technologicalcharacteristics from the original GIH. In overview, the GeoMap is implemented with athree-tier architecture which is a popular client-server architecture for webapplication. The three tiers include the presentation tier, the logic (application) tierand the data tier. The presentation tier refers to the client-side components of thesystem which include the user query interface and data representation interface. Theapplication tier consists of the functional processes to handle the user query and theprocessing of data. The data tier is composed of the spatial and attributes data, andfacilitates the data storage and retrieval.In GeoInfo Map, the Java Server Page (JSP) engine and the GIS components areinvolved in the application tier. Once the user accesses to the website, the HTMLinterface will be dynamically generated by the JSP engine. To respond to the queryfrom client-side, the JSP engine will facilitate the access to the database. The GIScomponent rasterize the layers of required datasets into image tiles and return themto the client-side interface. On the data tier, the relational database managementsystem (RDBMS) is used to handle the spatial and non-spatial data, and a spatialdatabase engine is involved to achieve the management of spatial data and theconnection with GIS. StrengthsBrowser-based ApplicationThe GeoInfo Map is a web-based GIS application that the user can easily access tothe system with a common web browser and Internet service. No additional softwareis needed to install. It can ensure that the accessibility to the general public withoutGIS background.The web interface is able to provide some spatial related multimedia to the user inadditional to the geometry and attribute data. For example, the geo-referenced sitephotos, the profile graphs of hiking trail, the related hyperlinks and such.Centralization of DataThe Geoinfo Map facilitates the centralization of the government geospatial data thatthe data from different bureaus and departments are put together under a commonsystem. This approach is beneficial to both user experience and technical view.To the end-user, time and effort would be preserved as the information from varied
data sources originally can be accessed under a common platform. In addition to thedigital map and the aerial photos from Survey and Mapping Office (SMO), largeamount of government information are geospatial-related, for examples, the hikingtrails information from the Agriculture, Fisheries and Conservation Department, thedeclared monuments information from the Antiquities and Monuments Office andthe facilities information from other departments. Before the establishment ofGeoInfo Map, the users may need to visit the varied government websites to seekthe spatial information they want. The process can be time-consuming and annoyingas there is no means to search the required information among the separated datastorage sites. Further, the usability of the data would be lower as this information isusually represented in form of still images only instead of GIS dataset. In the GeoInfoMap, the information from different sources can be accessed by a common querysystem and they can be considered at the same time in a common map frame.In the technical view, since the data are centralized in a common system, theduplicate GIS implementations with similar functionalities can be prevented. Thedemand of technicians responsible to system administration and data managementis also centralized. The resources can be therefore preserved. As the datasets aremanaged under a common system, the fidelity, consistency and up-to-dateness ofthe data can be maintained more easily.Multi-tier ArchitectureAs mentioned earlier, the GeoInfo Map is implemented with the three-tierarchitecture. Such kind of system architecture provides a great flexibility in systemdevelopment and maintenance (Wikipedia, 2011).The interface, the process logic and the data storage components are developed andmaintained independently and they can be operated on separated hardwareplatform. Since the application is broken into separated tiers, the modification onone of the components will not result in a re-write to the whole application. Itprovides desirable scalability to the overall system that an individual component canbe upgraded or replaced independently.In addition, the multi-tier architecture is also beneficial to the reusability of thefunctional components. For instance, Lands Department launched a new GIS productcalled “GeoMobile Map Hong Kong” on June 2011 (GovHK, 2011). This is actually amobile version of GeoInfo Map that providing mobile mapping service to thesmartphone users. The GeoMobile Map offers the geospatial data and data query
functions which are similar to the GeoInfo Map. However, the newly developed userinterface is optimal to the smartphone operation and multi-touch technology. Themobile positioning of the device is also integrated. This case reflects the superiorityof the reusability that the cost in the development of derived application and systemextension can be reduced. Limitations2D DatasetsThe design of GeoInfo Map is only deployed for providing 2D datasets distribution.Comparing to the 3D data, the visualization of 2D digital map is relatively abstractthat is similar to the traditional paper map. Since the 3D (or 2.5D) map data isbecoming popular in order to provide the more concrete views about cities, theattraction of GeoInfo Map may be reduced in the future.User- friendlinessThe access to the data of the GeoInfo Map is mainly executed by searching query.Due to the limitation of the system, the data shown on the base map will berefreshed every searching session. Therefore, it is impossible to display, compare oranalyze the resultant data retrieved by two or more searching query simultaneously.Spatial Query and Spatial AnalysisThe system only allows the user to input some key words or coordinates to searchthe geospatial information. The coordinates search is limited to the GPS receiver (orother positioning tools) user and it is not a convenient and reasonable method forthe general public to seek spatial information. The key word search function is largelydepended on the attribute data. The intelligent search function allows the user tofilter the specific facilities (e.g. hotel) in a particular district (e.g. Tsim Sha Tsui).However, there is no means to facilitate data query based on the spatial relationshipof the entities.Data ManagementIn the previous section, the benefits to a common data platform have been discussed.On the contrary, problems can be arisen also because of the centralization of theinformation from different data sources. Since the information in the GeoInfo Mapare collected from varied government departments that they may be stored indifferent data format and data structure with different quality. More planning andcommunication are needed to maintain the centralized information.
ImprovementsEnhancements on User OperationTo deal with the limitations mentioned before, some improvements to the useroperation on the system. First, query cache function should be implemented to storethe result from each searching sessions. The user can turn on or off the individualcache to control the representation of the selected sets of data. Therefore, the usercan analyze or compare the interested locations flexibly.Second, the spatial query or analyst tools should be integrated to the Map. Thesystem can provide the simple spatial functions such as buffering, selection bypolygon and seeking nearest facility to a user-defined point. It can enhance theGeoInfo Map from an information provider to a spatial decision-making supportsystem. For example, one can seek the nearest Accident and Emergency Departmentservice around his/her current location. And the parent can filter the schools within aspecific distance from their home.Integration of other GIS ServiceApart from the GeoInfo Map, there are also some other GIS project implemented byother government department to provide spatial information and specificfunctionalities to the public. For examples, the Statutory Planning Portal (SPP) fromTown Planning Board (TPB) is an online GIS to offer the latest statutory plan andplanning information. It provides a map frame to display the zonings overlaying on abase map. Further, the Hong Kong eTransport is a public transport routepoint-to-point search service for Hong Kong. It provides a map interface for settingthe origin and destination, and displaying the boarding and alighting points.The GeoInfo Map provides plenty of geospatial data and a strong searching engine.The SPP and eTransport can be integrated with the GeoInfo Map to improve the mapviewing quality and user experience. The base maps of the former systems aresignificantly simple and only show the relevant information. Although the originalmap system may be already enough to support its basic functions, the additionalinformation can enhance the overall usability since the geographic entities can berelated with each other physically or sociologically. The rich map information canprovide extra potentiality to the integrated systems in order to facilitate a betterdecision making process.
However, the integration of systems among the different departments should beeven more challenging than the integration of data. The difficulties may be comefrom the non-interoperability of the current applications and the distant informationpolicy of different departments. ConclusionIn this essay, the background information and the technology employed in theGeoInfo Map were introduced. GeoInfo Map is an online GIS application provided byHKSAR government. It provides abundant amount of geospatial-related informationto the general public via the Internet. The Map also acts as a common platform forpublishing the spatial information from different government bureaus anddepartments. It improved the efficiency of the public access to the governmentgeospatial information. The system architecture implemented in the Map istechnically flexible for system development and enhancement. The GeoMobile MapHong Kong is a recent derived application for mobile users based on the GeoInfoMap.On the other side, this map system is limited by its defeats on the user operations. Inaddition, the data management to the large-scale centralized geospatial-related datacan be a problem if there is no well planning and communication among thestakeholders. Finally, the usability of the system can be improved by providing thespatial query and analysis functionalities. These spatial functions can be beneficial tothe general public also. The involved GIS resources can be further utilized adequatelyby integrating other public GIS application, in order to provide a more completegeospatial information portal to the citizens. However, new challenges must be facedin the integration of separated systems.
Reference1. GIS for Everyone: The Newly Launched HKSAR GeoInfo Map (2010). Retrieved October 22, 2011 from ESRI China (Hong Kong) Web site: http://www.esrichina-hk.com/news/localNewsArchive.aspx?year=2010&month= 6&id=32. Government launches mobile mapping service (2011). Retrieved October 22, 2011 from GovHK Web site: http://www.info.gov.hk/gia/general/201106/22/P201106220335.htm3. Government map service goes online (2010). Retrieved October 22, 2011 from Survey and Mapping Office Web site: http://www.landsd.gov.hk/mapping/text/news/news20100526.htm4. Hong Kong eTransport (N/A). Retrieved October 22, 2011 from Hong Kong eTransport, Transport Department Web site: http://hketransport.gov.hk5. Multitier architecture (2011). Retrieved October 22, 2011 from Wikipedia Web site: http://en.wikipedia.org/wiki/Multitier_architecture6. Statutory Planning Portal (N/A). Retrieved October 22, 2011 from Statutory Planning Portal, Town Planning Board Web site: http://www.ozp.tpb.gov.hk7. Tsoi, C. W. (2007). HKSAR Geospatial Information Hub (GIH) - A Common Geospatial Information Platform and Spatial Data Portal. FIG working week 2007.