introduction to geographic information system

8/10/2019 Introduction To Geographic Information System

1/36


2/36

Lesson Objectives

Understand how a GIS functions

Understand what a GIS is

Look at some GIS applications

Understand how spatial data isrepresented in a GIS


3/36

Data vs.Information

Data, by itself, generally differs frominformation.

Data is of little use unless it is transformedinto information.

Information is an answer to a questionbased on raw data.

We transform data into informationthrough the use of an Information System.


4/36

INFORMATION SYSTEMOVERVIEW


5/36

What is an InformationSystem?


6/36


Information systems can be very simple,

such as a telephone directory.

Data

Storage

Information System

Query

Information

Wh i I f i


7/36


In the digital environment we use software to

create complex information systems.


8/36

What is a GIS?

A means of storing,

retrieving, sorting,

and comparing

spatial data

to support some

analytic process.

+

Information System

Geographic Position


9/36

GIS links graphical features (entities) to tabular data(attributes)

What is a GIS?

GEOGRAPHIC Information System


10/36

A GIS is a system (hardware + databaseengine) that is designed to efficiently,

assemble, store, update, analyze, manipulate,and display geographically referencedinformation (data identified by theirlocations).

A GIS also includes the people

operating the system and the datathat go into the system.

GIS Definition


11/36

Data can be:

1. Positioned by its known spatialcoordinates.

2. Input and organized (generally inlayers).

3. Stored and retrieved.

4. Analyzed (usually via a RelationalDBMS).

5. Modified and displayed

Key Functions of a GIS

Geographic Information


12/36

Decision

GISProcessOutput

GIS

analysis

Import or

build datasets

Define GIS

criteria

Define

problemDecision

GISProcessOutput

GIS

analysis

Import or

build datasets

Define GIS

criteria

Define

problem

Geographic InformationSystems


13/36

MODELLING AND

STRUCTURING DATA

(How we represent features or spatialelements)

Representing Spatial


14/36

Representing SpatialElements

RASTER

VECTOR

Real World


15/36

Entity Representations

Points - simplestelement

Lines (arcs) - set ofconnected points

Polygons - set ofconnected lines

We typically represent objects in space as three

distinct spatial elements:

We use these three spatial elements to represent real world features andattach locational information to them.


16/36

Raster vs. Vector

RasterAdvantagesThe most common data format

Easy to perform mathematical and overlay operations

Satellite information is easily incorporated

Better represents continuous- type data

VectorAdvantages

Accurate positional information that is best for storing discretethematic features (e.g., roads, shorelines, sea-bed features.

Compact data storage requirements

Can associate unlimited numbers of attributes with specific features


17/36

GIS FUNCTIONALITY

(What do they do?)


18/36

Data Assembly

Data Storage

Spatial Data Analysis andManipulation

Spatial Data Output

GIS Functions


19/36

GIS Functions

Data Assembly

Maps RSI

Intel Database Direct Entry

Keyboard

GPS


20/36

Data Input/Creation

GIS F i


21/36

Spatial data(ARC functions)

Attribute data(INFO or TABLES functions)

1 (Universe polygon)

2 3

4 5

GIS Storage

3

COV# ZONE ZIP

1 02 C-19 22060

3 A-4 22061

4 C-22 22060

5 A-5 22057

GIS Functions

3 A-4 22061

GIS F ti


22/36

Common Manipulation

Reclassification

Map Projection changes

Common Analysis

Buffering

Overlay

Network

Spatial Data Manipulation and Analysis

GIS Functions

Spatial Anal sis


23/36

Spatial Analysis

Overlay function creates new

layers to solve spatial problems

GIS F ti


24/36

Tables

Maps

Interactive Displays

3-D Perspective View

Spatial Data Output

GIS Functions


25/36

SOME EXAMPLES

AND APPLICATIONS

Amphibious Assault


26/36

Amphibious AssaultPlanning

S ti l A l i


27/36

Spatial Analysis

Proximity Analysis (Buffers)

1000 Meter Buffer of Railroads

Fli ht Pl i


28/36

Flight Planning

Flight Planning/Flythroughs


29/36

Flight Planning/Flythroughs

Other GIS Applications


30/36

Other GIS Applications

Cross country movement

Route planning Intervisibility study

Facilities management

Airfield assessment

Road network analysis (convoys)

Propagation coverages

Observation post siting analysis

Perspective views

Facilities Management


31/36

Facilities Management

Airfields


32/36

Airfields

Network Analysis


33/36

Network Analysis

A t P ti C


34/36

Antenna Propagation Coverages

Perspective Views


35/36

Perspective Views

SUMMARY


36/36

SUMMARY

Key Concepts

Data representation

Applications

introduction to geographic information system

Documents