Download geography 20 – introduction to gis

GEOGRAPHY 20 – INTRODUCTION TO GIS
EXAM 3 STUDY GUIDE
VICKI DRAKE
EARTH SCIENCE DEPARTMENT
SANTA MONICA COLLEGE
Data Management
What is a Spatial Database? Can a database be used by two different
Organizations for different purposes?
Two approaches to Database Management: File Processing and Database
Management – Similarities? Differences? Operations? Advantages and
Disadvantages?
Database Elements: Entity, object, attribute, attribute value, feature,
Spatial object type, spatial primitives, symbol, database models,
Layers (themes, coverages)
o-dimensional object type
1-dimensional object type
2-dimensional object type
Database Models: Hierarchical, Network, Relational – Advantages and
Disadvantages of each type – Which one is used most often in a GIS?
(Be able to define, describe, compare and contrast each of these Database
Models – see Chapter 6 in Aronoff’s book)
Database Structure – Tables, Queries, Tuples (Record row), Records,,
Fields, Key Fields (Primary Key),
(Digital Cartographic Data Standards Task Force terminology)
“Data” vs. “Information”
– Information systems function
Geographic Data structures: Descriptive element – Graphical Element
Four components of information systems – traditionally
Main component driving Information systems today
Data item (attribute), data file (flat file – hierarchical file), character
Strings, numeric strings,
Four perspectives of Information Systems:
1. Data Perspective, (Descriptive or
Graphical Elements using either Raster Data method or Vector data method)
Object view – Field View
2. Relationship Perspective – categorical relationships or spatial
Relationships (Categorical): Classification system Nominal, Ordinal, Interval
Ratio)
Spatial: Topological, Proximal
3. Operating System Perspective (OS)
Directories – subdirectories - GIS “Workspace” concept
4. Application Architecture Perspective
Client/Server concept and implementation
Descriptive Data Structure
Object-Oriented Data Structure
Type Constructor
Graphic Data Structures (Raster/Vector)
Raster Data Structure
How represented? What is tessellation? Why use Raster format?? What is a TIN? What is a
Quadtree? What is a run-length encoding compression? How is a Raster created? What are
Raster data values? How is raster data stored?
© Vicki Drake
SMC – F-2000
1
Vector Data Structure
How represented? Why use? How create? What is topology and how does it relate to
Vector? What is “Adjacency” , “Connectivity”, “Containment” in terms of topology? How is
Vector data stored? What is the Spaghetti Model of Vector Data? What is the Hierarchical
Model of Vector Data? What is the Topological Model of Vector Data? Which one is more
useful in a GIS? How is Vector data stored in each of these models? What is a Georelational
Data Structure in Vector Data model?
What are the Advantages or Disadvantages of using either a Raster Data Model or a Vector
Data Model?
GIS Analysis Functions
Questions – functions – answers
Basic spatial analysis: sorting, arithmetic, Boolean, statistical
Logic Operations
General Arithmetic Functions
Rubber sheeting, data layers, rectification vs. registration, sliver, undershoot,
overshoot, slope, aspect, buffer zones,
Classification and reclassification processes Integrated processes
Organization of Geographic Information within a GIS
Four major groups of GIS analysis functions:
Maintenance and Analysis of Spatial data
(format, geometric, and map project transformations; conflation, edgematching, graphic element editing, line coordinate thinning)
Maintenance and Analysis of Attribute Data
Attribute editing functions, attribute query functions,
Integrated Analysis of Spatial and Attribute Data
Retrieval, classification and measurement functions, Overlay
Operations (see notes), clipping, merging of polygons, ‘neighborhood
operations’, topographic functions,
Output formatting (reports, maps, etc.)
What are the Boolean operations possible using Vector Data? What is reclassify, dissolve,
and merge in relation to Vector Data operations and polygon overlays? What are sliver or
spurious polygons in Vector data operations?
© Vicki Drake
SMC – F-2000
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