GIS Intro Lecture-1

8/13/2019 GIS Intro Lecture-1

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M. Khubaib Abuzar

Assistant Professor

CSC-430 GIS & Computer Image

Processing

Bahria University

GIS

Introduction& Overview


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A system of hardware, software, and

procedures

designed to support the capture,

management, manipulation, analysis,

modeling, and display of spatially

referenced data

for solving complex planning and

management problems.


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While accurate,comprehensive, and

widely accepted

this definition is verycryptic to a GIS

newcomer.


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A computer system which

can hold and use datadescribing places on the

earth's surface.


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This definition also leaves out the

most important component of theGISthe people who administrate,

use, and manage the GIS.


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a computer system capable of

assembling, storing, manipulating,

and displaying geographically

referenced information (USGS,

1997)

a set of computer-based systems

for managing geographic data and

using those data to solve spatial

problems (Lo & Yeung, 2002)


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GIS is BIG Business Now GIS is the primary driver for its very own, ever

greater, acceptability and use. Everyone likes maps and graphics and the computer

makes it easier for you to visualize your data.

GIS growth feeds on its own successes and builds

new and more complex applications as it permeates

society.

It is projected that $75 to $95 BILLION dollars will

be spent in the United States alone on GISimplementations through the year 2000.

The market has grown over 40% per year with no

stopping for several years now.


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Most common practical applications:

Analyze how the environment is affected by man

Mapping out environmental layers to characterize a siteand predict site potential

Routing of roads, transmission lines, pipelines, sewer,

and network analysis / flow analysis through thesetransportation routes.

Mapping and managing urban infrastructure including

base maps, tax, curbs, water supply, drainage,

electricity, telephone, and gas.

Spatially examining socio and economic indicators of

the population and their use in planning and growth

management.


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There are literally thousands of

applications of GIS!!

Because no project is ever

started without first asking:

Where??


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Who benefits from the GIS Application?

People responsible for the infrastructure -whether you watch it, study it, design it,

repair it, sell it, own it, manage it, defend it,

or just use it.

GIS, once installed to serve a local

government, can act as a magnet pullinglocal citizens back to an appreciation of

local political leadership.


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GIS data

types geodetic control network: surface location

topographic base: point elevation

graphical overlays: thematic data

representation vector: point, lines, polygons

raster: grid cells

surface

metadata

information about the data

key when sharing data


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GIS technology hardware

organization

intranet: servers & client computer stations

PCs

internet

considerations processing power

file size (very large)

data access


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GIS technology

software

proprietary

open standard

companies

ESRI

ArcInfo & ArcView

ArcGIS

Intergraph

MapInfo


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VISION

Create and promote anefficient GIS environment

that fosters cooperation

and data sharing.


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Components of GIS

Database

Computer Hardware & Software

Organizational

Structure & People


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Questions a GIS canAnswer

A comprehensive

GIS can answer all

of the followingquestions...


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GIS generations information - locations

Who owns the lot at 3233 Texas Street, and what is it zoned for?

Identifier: 565-88-221

Area: 108,900,245

Owner: John Morris

Address: 3233 Texas St.

Zoned land use: Industrial

Assessment: $950,000


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Instead of identifying what exists at a givenlocation, you want to find a location where

certain conditions are satisfied.

For example, you wish to find a house

assessed at less than $200,000 with 4bedrooms and made of wood or stucco.


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GIS generates information - conditions

Where are houses located that you might consider buying?

Residential land use

Assessed at less than $200,000

4 bedrooms

Made of wood or stucco


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This seeks to discover thedifferences between an area as

the result of the passing of time.


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GIS generates information - trends

How much land has gone from agriculture to other uses since 1950?

Smallville in 1950 Smallville in 1990


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This seeks to discover what types ofpatterns may exist in the newly createddata file that were not visible before.

For example you may wish to know

where motor vehicle accidents occurand at what times.


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GIS generates information - patterns

What kinds of patterns exist for motor vehicle accidents?

Where do they occur and at what times?


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This seeks to determine what happens if

something is changed within an area.For example a new subdivision is addedto a school district, or a toxic substance

seeps into the local ground watersupply, or an earthquake of a givenmagnitude occurs at a given point, oryou want to locate a new business.


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GIS generates information - models

If you wanted to open a new facility, where would you locate it?

School

Childrens

Bookstore

Hospital

Restaurant

?

?

?

?


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GIS...

...is an analysis tool.

...links spatial data with geographic

information about a particular feature on a

map.

...can use the storedattributes to compute new

informationabout map features.

A GIS is not simply a computer system formaking pretty maps. More importantly a GIS...


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In short, a GIS does

not hold maps or

pictures -- it holds a

database from which

the data can beviewed in a new light.


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1. What it is.

2. Where it is.3. How it relates to other features.

If you want to go beyond just making pictures,

you need to know three pieces of information

about every feature stored in the computer.


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Geographic Features

Geographic features are represented by two types of data.

SPATIAL DATA ATTRIBUTE DATA

Street NameAddress range on leftAddress range on rightLength to travelDirections to travel


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The Geographic Database

Spatial and attribute data types are

linked together by a common

identifier.

Geographic Database


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Major Areas of Practical

Application of GIS Technology

Street Network-Based

address matching

vehicle routing and

scheduling

location analysis,

site selection development of

evacuation plans


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Facilities Management

locating underground pipes,cables

balancing loads in electrical

networks

planning facility maintenance tracking energy use


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Land Parcel-Based

zoning, subdivision plan review

land acquisition

environmental impact statements

water quality management

ownership of maintenance

M j A f P ti l


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Natural Resource-Based forest management

Water resources assessment and management

wildlife habitat, migration routes management

wild and scenic rivers preservation recreation resources planning

floodplain management

wetland preservation

agricultural lands management groundwater modeling and contamination

tracking

environmental impact analysis

Watershed analysis


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Data Model

based on

Inventory ofdata layers


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Spatial Data: Vector format

Point- a pair of x and y coordinates(x1,y1)

Line- a sequence of points

Polygon- a closed set of lines

Node

vertex

Vectordata are defined spatially:


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Themes or Data Layers

Vector data: point, line or polygon features


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Kissimmee watershed, Florida

Themes


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Attributes of a Selected Feature


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Raster and Vector Data

Point

Line

Polygon

Vector Raster

Rasterdata are described by a cell grid, one value per cell

Zoneof cells


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Santa Barbara, California


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How do we combine these data?

Digital Elevation

ModelsWatersheds Streams Waterbodies


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An integratedraster-vector

database

GIS Intro Lecture-1

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