Attribute data input and data display : Attribute data in GIS, Relational model, Data entry, Manipulation of fields and attribute data, cartographic symbolization, types of maps, typography, map design, map production

1. GEOGRAPHICAL
INFORMATION
SYSTEM
UNIT 3
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2. WE-IT TUTORIALS (PH:8097071144/55)

3. Attribute Data in GIS
 Attribute data are stored in tables.
 An attribute table is organized by row and column.
 Each row represents a spatial feature,
 each column describes a characteristics,
 and the intersection of a column and a row shows the value of
particular characteristic for a particular feature
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LabelID pH Depth Fertility
1 6.8 12 High  Row
2 4.5 4.8 Low

Column

4. Relation Model
 A database is a collection of interrelated tables in digital format.
There are at least four types of database designs that have been
proposed in the literature:
 flat file,
 hierarchical,
 network, and
 relational.
 GIS vendors typically use the relational model for database
management. A relational database is a collection of tables, also
called relations, which can be connected to each other by keys.
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5. SSURGO
 The Natural Resources Conservation Service (NRCS)
produces the Soil Survey Geographic (SSURGO)
database nationwide
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6. what is meant by
Normalization
 Normalization is a process of decomposition, taking a
table with all the attribute data and breaking it down into
small tables while maintaining the necessary linkages
between them
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7. types of relationships among
database tables
 onetoone,
 onetomany,
 manytoone, and
 manytomany.
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8. how to Manipulate fields of
Attribute Data in GIS
 Manipulation of Fields and Attribute Data
 Adding and Deleting Fields
 Classification of Attribute Data(grouped)
 Computation of Attribute Data(formula)
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9. Cartographic Symbolization
with its various aspects.
 use a map symbol to indicate the feature’s location
 example, a thick line in red may represent an interstate highway and a
thin line in black may represent a state highway
 Use of Color
 If maps are black and white (lighter and darker shade is used)
 Data Classification(aggregating data and map features)
 Equal interval(0110, 1120, 2130, etc)
 Equal frequency(class contains the same number of data values)
 Mean and standard deviation(above or below the mean)
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10. types of maps in GIS Packages
 The general reference map is used for general purposes
 The thematic map is also called the special purpose map, because its main
objective is to show the distribution pattern of a theme, such as the
distribution of population densities by county in a state.
 A qualitative map uses visual variables that are appropriate for portraying
qualitative data
 dot map
 choropleth map
 graduated symbol map
 pie charts
 flow map
 isarithmic map
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11.  role of Typography in GIS?
 Map Design with reference to : (a) Layout (b) Visual
Hierarchy?
 process of Map Production?
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12. END OF UNIT 3
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