Week 1: What is GIS?

ENV208/ENV508 – Applied GIS

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WHAT IS GIS?

A GIS integrates hardware, software, and data for capturing,

managing, analyzing, and displaying all forms of

geographically referenced information.

GIS allows us to view, understand, question, interpret, and

visualize data in many ways that reveal relationships,

patterns, and trends in the form of maps, globes, reports, and

charts.

A GIS helps you answer questions and solve problems by

looking at your data in a way that is quickly understood and

easily shared.

http://www.youtube.com/watch?v=-ZFmAAHBfOU

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WHAT IS GIS?

G = Geographic

• Implies that data items have known spatial locations

on the Earth’s surface (or they can be calculated)

– Spatial vs. aspatial data

• Relative location (where things are in relation to

everything else)

• Geography theory and techniques form the basis of

GIS

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WHAT IS GIS?

I = Information

• Data are organised to generate knowledge

• Factual and interpretative

• Output: maps, images, graphs, tables, analysis

results…

• Information technology (e.g. computer systems)

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WHAT IS GIS?

S = Systems (Science, Studies, Services..)

• Made up of several inter-related and linked

components/subsystems

• Capable of data:

– Capture

– Storage

– Input

– Manipulation and transformation

– Visualisation, query, and analysis

– Output 5

WHAT IS GIS?

Simplest definition – three components

1. Database (table of information)

2. Spatial data (geographic information)

3. Links between the two

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WHAT IS GIS?

1. Database (table of information)

Total population

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WHAT IS GIS?

2. Spatial data (geographic information)

State/Territory

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WHAT IS GIS?

3. Links between the two

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WHAT IS GIS?

GIS organises the data into a map, and also facilitates much

more.. By using a data layer approach

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Geographic data are linked to attribute data in Geographic

information Systems

WHAT IS GIS?

WHAT IS GIS?

Core of GIS = Layers

• Each layer is brought together

based on spatial data.

• It’s the bringing together of all of

this data, and being able to see the

relationships between these data,

that makes GIS such a powerful

tool.

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WHAT IS GIS?

• The data can be related to

anything… roads, hospitals,

houses in an urban setting; or

forest patches, water bodies,

animal nests.

• Once in a GIS, all of the data can

be investigated to test the

relationship between different

parameters because they are

linked spatially.

• Aspatial data is of limited value

until they can be attributed to a

location

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WHAT IS GIS?

Data layers must be

aligned with one another

Needs a referencing

system

More on datum's and

map projections later in

the unit..

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Vector • Points, lines and polygons e.g.

topographic maps

• Discrete geographic features

• Shapefile, KML, GML, GPX…

Raster • Grid cells or pixels e.g. satellite images

• Continuous geographic features

• GeoTIFF, JPEG2000, HDF5, IMG, NetCDF, Esri GRID…

TWO MAIN DATA STRUCTURE TYPES

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X

Point

(City location)

Line

(Road)

Polygon

(Fire extent)

x

Node Vertex

TWO MAIN DATA STRUCTURE TYPES

Vector

– a graphic data structure represented by points, lines and polygons using exact x, y coordinates.

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Industrial

Vegetation

Lake

Residential

TWO MAIN DATA STRUCTURE TYPES

Raster

– A regular grid of cells covering an area

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2 main types of data structure

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WHAT GOES IN AND COMES OUT

OF A GIS?

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COMMON INPUT DATA FOR GIS

• topographic

• cadastre

• geology

• hydrology

• land cover/vegetation

• soils

• elevation

• census data

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Geographic data:

– Topographic maps

– Satellite and airborne scanner images & photos

– Administrative boundaries

– Statistical data on people, land cover & use

– Data from marketing surveys

– Data on utilities

– Data on land form, water, biological activity,

natural hazards & disasters

COMMON INPUT DATA FOR GIS

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COMMON INPUT DATA FOR GIS

Remotely sensed imagery and products can be very useful

WHERE CAN YOU GET INPUT DATA

FROM?

• National mapping agencies

• Local government

• Military

• Remote sensing companies and satellite

agencies

• National resource surveys

• Scientists

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COMMON OUTPUT FROM GIS

• maps

• tables

• charts

• statistics

• reports

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WHY USE GIS?

• To explore relationships between features

distributed unevenly over space

• To seek out patterns that may or may not be

apparent without using the query, selection,

analysis and display functions

• Make maps to communicate

information

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WHY USE GIS?

• faster and easier than manual methods

– labour saving

• can handle large volumes of data

• have spatial and temporal analysis capabilities

• useful decision making tools

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WHY USE GIS?

Examples of questions that can be answered using GIS

• Does it make sense to put a shopping centre here?

• Do we expand the existing airport here or build a new one over there?

• Which pockets of endangered wildlife should we protect?

• What is the impact of waste facilities on local health patterns?

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GROUP ACTIVITY

• How might GIS be used?

• What spatial questions might be asked?

• What kind of data might be needed?

• What would the output be?

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WHERE GIS IS BEING USED

• Business

• Marketing

• Public Safety

• Disaster Response

• Medical Services

• Utilities

• Military

• Transport

• Local Government

• Environment

http://www.youtube.com/watch?v=4M0q9INPYHc

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• Professionals in every field are becoming

increasingly aware of the advantages of using GIS

WHERE GIS IS BEING USED

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• As a GIS analyst, GIS programmer.. A position that is

explicitly GIS

• As a biologist, ecologist, real estate professional where

GIS is a fundamental tool and a way of thinking

WHERE GIS IS BEING USED

GIS IN CONSERVATION

• Where a species is

• Where a species could be

• Helps identify distribution information

• Helps identify locations of high biodiversity importance

– guide decisions about policy and action needed to protect these areas and species

• Allows businesses and researchers access to biodiversity information to guide decisions

• http://www.iucnredlist.org

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Relevance of GIS to society

• Name some areas of concern in your community,

region, country, world

– Energy, sustainable agriculture, natural hazards,

epidemics, biodiversity, transportation, water

quality, climate change, migration and

urbanisation

• All of the key issues have a geographic component and

therefore can be better understood and solved using

GIS

SPATIAL QUESTIONS

Law enforcement:

Where in the city are the majority of the drug arrests made? Where do most of the violent crimes occur? Is there a spatial relationship between these two variables?

Realtor:

What is the average price of homes in this neighbourhood relative to those in nearby neighbourhoods?

University admissions administrator:

Where do most of the student applicants live? Where are the economically disadvantaged areas? How can we attract more applicants from these areas?

Aid worker:

Where is the area of greatest human suffering and greatest poverty damage? How can we maximise the impact of our relief efforts?

Delivery truck driver:

What is the most efficient route for my 25 deliveries today?

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What GIS can do…

• GIS allows you to bring together many types of data

together based on geographic location of the data

• Can integrate, visualise, manage, question, interpret

and present this information using GIS

• Allows you to identify relationships in your data

SUMMARY

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SUMMARY

• GIS has the power to

– create maps

– integrate information

– visualise scenarios

– solve complicated problems

– present ideas

– develop effective solutions

• To use GIS effectively need to learn to think spatially, know the correct procedures for analysing your data and how to communicate your findings

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COMING UP…

Practical session 1

• Test login

• Start ESRI Virtual Campus module 1

• Use the time to ensure personal computers are

running ArcGIS properly

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COMING UP..

• Week 2:

– Making maps, data visualisation and other GIS

outputs

– Module 2: Creating Map Symbology

• Week3:

– Coordinates and Projection systems

– Module 3: Referencing Data to Real Locations

– Module 4: Organizing Geographic Data

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• This course requires a lot of computing work but assumes no

previous computing knowledge

• Learning curve for computing laboratories

Week 4

Week 3

Week 2

Time

Kn

ow

led

ge

Words of encouragement..

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