ATTRIBUTE DATA ANALYSIS
Attribute data tells the characteristics of different objects / features on the earth surface. These are descriptions, measurements or classification of geographic features. Attribute data can be both qualitative (like land use type, soil type, name of the city/river etc.) and quantitative (like elevation, temperature, pressure of a particular place, crop yield per acre etc.). So, the attribute can be both numeric and textual. The examples of attribute data of different spatial features like point (well), line (river), area (village) are shown in box 1. The attribute data are generally in tabular form.
Different Types Of Spatial Data Analysis Can Be Performed By Gis, Viz. Performing Queries, Proximity Analysis, Network Analysis, Overlay Operations, and Model Building Etc. Since Gis Stores Both Spatial And Non Spatial Data And Links Them Together, It Can
Perform Different Types Of Queries.
For Example By Joining The Spatial Data And Its Attributes. And Then By Performing Queries, One Can See On Map, The Water Of Which Tube Wells Having Chlorine Content More Than 200 Mg/Litre. Likewise One Can See On Map). The Roads Constructed Before 1980 Which Need To Be Repaired. In The Same Way, Which Area Of A Given Forest Having More Than 60 Per Cent Tree Density, Can Be Shown On The Map (By Joining Map Of The Forest Shown In Figure 6 And Its Attribute Table Given In Table 3)
Can Be Done Through Buffering, I.E. Identifying A Zone Of Interest Around A Point, Line Or Polygon. For Example, 10 M. Around On Tube Well Can Be Marked For Planting Flower Plants; Or 50 M. Along National Highways (Both Sides) Can Be Buffered For Planting Trees. A Specified Distance Around The Forest Can Be Buffered As No Habitation Zone.
Is Another Important Analysis Done Through Gis. For Example Optimum Bus Routing Can Be Determined By Examining All The Field Or Attribute Data (Given In Table 2) Linked To Road Map / Spatial Data.
Can Be Done Through Gis By Overlaying / Integrating A Number Of Thematic Maps. Overlay Operation Allows Creation Of A New Layer Of Spatial Data By Integrating The Data From Different Layers. For Example, A Particular Land Use Class Having Saline Soils, Slope Less Than 20%, Drainage Density Less Than 10 M. Per Squre Km. Can Be Created From Four Different Thematic Maps, Viz. Land Use Map, Soil Map, Topographic Map And Water Resource Map.
Model Building Capability Of Gis Is Very Helpful For Decision Makers. It Is Usually
Referred To As 'What If' Analysis. For Example, If A Certain Amount Of Water Is Released
From A Dam, How Much Area Would Be Inundated?