[E-Business with GIS] Movie

(Review of Unit-3 Questions....)

GIS Data Format:

 A.   Raster Data Model and File Compression

(http://en.wikipedia.org/wiki/Image:Rgb-raster-image.png)

Encoding Method:

 Use compression technologies; wavelet compression techniques (MrSID, ECW)

http://en.wikipedia.org/wiki/Wavelet_compression .

http://www.cs.sfu.ca/CC/365/li/material/misc/wavelet.html

Size of Images:  How many bands (Layers)?  What's the storage size for each pixel? (2 bits?, 8 bits (One byte)?  24 bits (3 bytes)?

(Four Bands -- First-Blue,  Second-Green, Three (not used), Four-RED). 

(The size of each pixel)

Images size: 24MB

Image size: 8MB

Image size: 4MB

Image size: 1MB

Discussions: What are the advantages and disadvantages of raster data models?

B. Vector Data Model

(http://www.sli.unimelb.edu.au/gisweb/GISModule/GIST_Vector.htm)

Vertex: any point on the polygon where two sides (line segments) meet or connect.

Vector model = simple features + topological relations.

Features are vector objects of type point, polyline, or polygon. (p. 184),

Topology is the science and mathematics of relationships used to validate the geometry of vector entities, and for operations such as network tracing and tests of polygon adjacency. (p. 184)

ESRI ARC/INFO  Topology

(Image from ESRI lecture notes)

###.AAT (Arc Attribute Table)

Discussion: Why we need topology?  (Data validation, editing, consistency, query efficiency)

Discussions: What are the advantages and disadvantages of vector data models?

(See http://www.innovativegis.com/basis/primer/concepts.html)

TIN Data Model

Triangulated Irregular Networks (TINs)

 TIN is used to create, store, analyze and display surface information. 

Images from ESRI ARC/INFO help file.

Images from ESRI ARC/INFO help file.

Images from ESRI ARC/INFO help file.

TIN Data Model Advantages:

l      Compact Data format (save disk space).

l       Consisting of irregular nodes and lines;

l       Accurately describing the relief;

l       Topological vector structure;

l       Flexible and efficient in terms of storage space;

More information about TINs:

 http://www.ian-ko.com/resources/triangulated_irregular_network.htm

　

Object Data Model

 

　

Images from the Book:  Object-Oriented Modeling and Design
by James R Rumbaugh (Author), Michael R. Blaha (Author), William Lorensen (Author), Frederick Eddy (Author), William Premerlani (Author)
http://www.amazon.com/Object-Oriented-Modeling-Design-James-Rumbaugh/dp/0136298419

　

　

More resource:

http://java.sun.com/docs/books/tutorial/java/concepts/object.html

 

Youtube Video:   http://www.youtube.com/watch?v=NtfJxA1J3h8

　

　

UML:  Unified Modeling Language.

Discussion:

Give ONE examples of objects and their attributes.

What are the advantages of object model?

 What is a “class” and what is a “rule”?

(Attribute rules, connectivity rules, relationship rules and geographic rules)

 

Object-Oriented GIS data model ? (Not really.  Most of current GIS databases are still [Relational Database].

Hybrid GIS Data Model (Relational + OO)

 

　

Unit-4  In-Class Discussion Questions:

1. Please find ONE commercial-based software package (Not limited for GIS, the software could be any kinds) and ONE open source software package (with their URLs -- Web address) and discuss the advantages and disadvantages between the two software.

　

2. Please create and define THREE "related" Data Objects by following the rules of Object-Oriented Modeling and explain the three Objects' attributes, behaviors, and their relationships.  (All three objects must be related to each other).  Draw a diagram of the three objects by following the [Object Model Notation].  

　

　

　

　

　

  
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and Geography Department.

This web site is hosted on MAP.SDSU.EDU and Geography Department.