Database Integration
The process of establishing a linkage between a spatial feature located on a map, to its respective non-spatial or attribute information is termed as database integration. For this purpose MicroStation/ J Geographics (Ver. 7.1) has been used for project creation and database integration.
Web launching of the application
Using Model Server Discovery, the web component of MicroStation/J Geographics the application has been customised so that the end users can make queries on the DSS on the web using Internet Explorer or Navigator or other popular web browsers, anytime, anywhere. By using SVF (Simple Vector Format) type of image publishing on the web, it is possible for the end user to zoom in/out, turn on/off the layers etc. dynamically.
Sample Queries and Validation of results
In the DSS built it is possible to make three types of queries. They are:
- Attribute Filter Queries
- Spatial Filter Queries and
- Attribute and Spatial
Filter Queries (Combination of the above two
queries).
A query in GIS terminology is a request for information from the database built. In an attribute-filter query, it is possible to identify the features desired by defining an attribute filter. This can be accomplished using the visual SQL query builder. On the other hand Spatial queries can be made by using the generate zone tool available in MicroStation/J Geographics. A combination of the above two types of queries can also be made.
A typical attribute filter query is given below
NAME_OF_THE_AGENCY LIKE ‘A’ AND APARTMENT_LOCATION =
‘TNAGAR’ AND AREA_IN_SQM (SQFT) >
500OR COST_PER_SQM (SQFT)<1400OR DISTANCE_BUS_TERMINUS<1 OR DISTANCE_CITY_CENTRE <10 ORDISTANCE_EDUCNL_INSTITUTION<0.5 OR DISTANCE_HOSPITAL<0.5OR DISTANCE_RAILWAY_STN < 1
The meaning of this query is that the buyer making the query wants to buy an apartment from company “A” and the apartment should be located in T. Nagar
and the area in Sqft should be more than 500 Sqm (Sqft) or the apartment should be less than Rs 1400 per Sqft and the bus terminus should be available at less than 0.5 Km from the apartment or the distance to City Centre should be less than 5 Kms or the educational institution should be available at less than 0.5 Kms from the apartment or the hospital facility should be available at less than 0.5 Kms distance or the railway station should be at less than 0.5 Kms distance from the apartment to be selected from the database of 30 apartments for sale. ( Fig. 2).
A typical spatial filter query:
SELECT FROM SITES FOR CONSTRUCTING APARTMENTS “THAT ARE WITHIN A DISTANCE OF” 1 KM FROM THE BUS TERMINUS
The meaning of this query is that the promoter wants to know how many sites out of the 15 sites in the database are within 1-Km distance from the bus terminus. The output shows that 7 sites satisfy the spatial condition made by the promoter. (See Figure 3)
Thematic Maps
In this type of maps geographic features are symbolised according to nongraphic attribute data through the use of color and other user-defined display properties. For example the apartments for sale included in the database can be displayed based on the Cost per Sqm (Sqft) of each apartment, so that a buyer can find out where he can buy an apartment, very well knowing his affordability per Sqft. Figure shows the thematic map by Cost per Sqft of the apartments, by various colour codes assigned to each cost range.
Validation of the DSS
Several sample queries were run on the DSS and the output generated by the DSS was cross-checked by manually verifying the same in the database.
Strengths of the DSS built
- The prospective buyer becomes informed about the apartments for sale in the market.
- The promoter becomes informed about the sites for sale in the market for constructing residential apartments.
- The buyer as well as the promoter can make quicker decisions with improved consistency and accuracy.
- The DSS allows for a user-friendly approach to
the buyers and the promoters.
Weaknesses of the DSS built
- A Query has been incorporated for DCR Compliance in the DSS. However, sufficient data could not be provided in the DSS as getting the sanctioned plan and verifying the ground truth would be a time consuming exercise.
- Field measurements of a plot, such as plot depth and width, width of the abutting road, land use etc are to be taken to assess the required set backs to be left, building height permissible etc for that plot. This would be possible only for organisations like CMDA, CCMC etc, which have an authority and manpower.
- The DSS built does not taken into consideration the legal aspects such as encumbrance in the title of the land.
- Crow-fly distance has been taken for analysing
the spatial disposition of apartments/sites in relation to the
infrastructure facilities such as educational institutions, railway
stations, bus terminus and hospitals.
Future directions
- A good Information System is said to be the backbone of any DSS. The ability of the DSS built, to respond to diversified queries can be increased by including more number of apartments/sites for sale, as well as attributes not considered in this study.
- As in other developed countries a system can be devised to make available all information about an apartment/site for sale to the public mandatory.
- The DSS built can be made available to the
common public at all levels starting from CMDA (Chennai Metropolitan
Development Authority), CCMC (Chennai City Municipal Corporation) and
all ULB’S for the buyers to enable them to take the right decision.
Acknowledgment
The author expresses his deep sense of gratitude and indebtedness to Dr. V. Shanmugasundaram, Assistant Professor and other teaching faculty of Division of Urban System Development, Anna University and Mr. N. Dharumalingam, Chief Urban Planner, Chennai Metropolitan Development Authority.
The author is profoundly grateful to Dr. T. Anantharajan, Professor Emeritus, Division of Urban System Development, Anna University.
The author is thankful to Mr. P. V. Rai, Managing Director, Pixel Infotek Pvt. Ltd., Bangalore. Special thanks to Mr.V. Nagarajan, Real Estate Consultant, Chennai.n