Composite Apartment Index (CAI) and Composite Site Index (CSI)
CAI/CSI is a combination of 10 factors on the basis of which it has been arrived at. Any buyer/promoter who does not have any special preferences over any one aspect, when making a decision to buy an apartment/select a site for constructing residential apartments, but is satisfied with an apartment/site which in comparison with the other apartments/sites listed in the database, is at close proximity to facilities like educational institutions, hospitals, railway stations, bus terminus; close to city centre, etc. The formula for calculating the Composite Apartment Index for an individual apartment for sale is as follows:
Where,
i = Number of apartments included in the database (in this case it is 30 )
The formula for calculating the Composite Site Index for an individual site is as follows:
Where,
i = Number of sites included in the database(in this case it
is 15 )
Ranking sites for constructing and sale of residential apartments
In order to work out the rank for various factors used in the calculation of CSI, for each individual site/apartment included in the database, the formula indicated earlier has been used. The weightages for the factors (Table 1) have been arrived from the analysis of the questionnaire survey conducted with the promoters. Taking into consideration the factors, same as those used for the computation of CSI, the 15 sites included in the database of sites for constructing residential apartments for sale within Chennai City have been ranked to arrive at the CSI for each site. The factors considered and the technique adopted for assigning ranks are as shown in Table 2. The ranking obtained in this manner for each factor for each site was then multiplied by the corresponding weightage for that factor to arrive at the CSI for that site. In ranking the residential apartments for sale, the procedure similar to that adopted for ranking the sites for constructing residential apartments has been used, with a small difference in the criteria for ranking the apartments in terms of availability of ground water. The criteria has been evolved taking into consideration the availability of ground water for purposes like all purposes, drinking and cooking, ablution purposes only and finally scarce availability of ground water. The following ranks have been assigned for availability of ground water different purposes:
v
All purposes especially Drinking and Cooking (Very good condition) = 1
Drinking and Cooking only (Good condition) = 2
Ablution purposes only (Satisfactory condition) = 3
Scarce
availability of ground water (Scarce condition) =
4
Building the DSS
The DSS has been built taking into due consideration the User, the System, the tool selected (GIS), and finally the problem to be addressed. The components of this DSS can be divided into two types, viz. Spatial and Non-Spatial.
The spatial component involves base map creation, where the graphical entities are represented spatially. The non-spatial component involves designing the database where the relevant information about the graphical entities is to be stored and retrieved for analysis.
Base map creation for the study area
A 1:25,000 scale TTK map of Chennai City was scanned and imported in the raster format for creating the base map of the study area, through onscreen digitising. MicroStation Descartes of Bentley Systems. has been used for semi-automatic R2V conversion. Using GeoDefiner, the coordinate and projection systems have been defined for the vectorised base map. The point features that have been included in the base map, have been geopositioned by keying in the latitude and longitude of the respective features. This is very much essential for accurately locating the position of new apartment projects on the map. The partial list of various features that have been included in the base map are: Roads, Railways, Water Bodies, RailwayStations, Bus Terminus, Hospitals, Educational Institutions, Greenery, various apartment projects, sites for new apartment projects etc. (Fig. 1)
Database design
Database is a subset of data elements taken from a databank and organised for storage and manipulation in a computer system. Database is the fulcrum of any Decision Support System. With the advancements in information technology, access to large and remote databases, hitherto available in the form of a CD-ROM, have now switched over to GIS maps. When data from different sources can be displayed in many different ways at the press of a few keys, then it is possible to gain insights and detect patterns which could not easily be achieved by other means. This is possible only with a tool like GIS.
In this project the database has been built using MS-Access. Non-Spatial database is nothing but the non-graphic information about a feature, stored in a table and linked to the feature. The residential apartments for sale represented graphically on the base map, contains the following attribute information:
- Name, Contact Address of the Agency promoting the Apartment
- Apartment Location and Address
- Apartment Area in Sqft
- Apartment Cost per Sqft
- Key Plan, Site Plan, Floor Plan, and Photo of the Apartment
- Distance to City Center
- Name of the Nearest Educational Institution
- Distance to Nearest Educational Institution
- Composite Apartment Index (CAI) for that Apartment
- Rank based on CAI for that Apartment
- DCR Compliance of the
Apartment, etc.
Similarly the following is the partial list of attribute information are available for the sites for constructing residential apartments for sale included in the database created:
- Name of the Seller and Address
- Site Area in Sqm
- Cost per Sqm
- Site Location and Address
- Willingness of the Seller for Joint Venture
- Name of the Nearest Educational Institution
- Distance to Nearest Educational Institution
- Ground Water Availability (Depth in Meters (Feet) )
- Drinking Suitability of Ground Water (Yes / No)
- Whether the property is with / without building
- Land Price (One Ground Price) at selected locations within Chennai City (1999-2000)
- Composite Site Index (CSI) for that Site
- Ranking based on CSI for that Site
- DCR Compliance of the
Site.
Additional information about an apartment has been created using MS - POWER POINT so that a buyer after selecting the apartment can go through this video show to get additional information such as materials used for various works, special features, other projects of the promoter of this apartment etc. The key plan, site plan, floor plan and apartment photo have been stored as image files in a separate directory and hyperlink given to the respective files. The trend in residential property prices has been shown in a graphical form by using Bar Graphs in MS-POWER POINT and Hyperlink has been given to the respective file under the attribute value field.