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.
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?