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
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
onetoone,
onetomany,
manytoone, and
manytomany.
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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(0110, 1120, 2130, 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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