lecture 04 - 07: introduction to gis · understanding gis requires consideration of science,...

Lecture 04 - 07:

Introduction to GIS

Geographic Information System (GIS)

By: Md. ESRAZ-Ul-ZannatAssistant ProfessorDepartment of Urban and Regional PlanningKhulna University of Engineering and Technology (KUET), Khulna-9203, Bangladesh

Date: 18 January 2015

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Acknowledgement

These slides are aggregations for better understanding of

the topic mentioned in the previous slide . I

acknowledge the contribution of all the authors and

photographers from where I tried to accumulate the info

and used for better presentation.

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Topics to be Covered by this Presentation

ArcGIS views Data Management – Database View

Analysis – Model View

Visualization – Map View

GIScience, GISystems, GIStudies & GIServices

Who needs Advantage GIS?

Why is GIS Important?

Why is GIS so HOT?

GIS Challenges

Why spatial is special?

GIS is not......

The future of GIS

Geographical information service

Ways of Collecting GIS Data

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Topics to be Covered by this Presentation

Possible Sources of GIS data

GIS Field of Applications

Major GIS Applications in Water Sector

Importance of Layers in GIS

How Do We Create Geographic Information?

Major Disciplines & Technologies

Ideal GIS

● Data Management –Database View

● Analysis –Model View

● Visualization – Map View

What is GIS?

● Data Management -

1. Manages various kinds of GIS data including vector,

raster, images, tables, other data files

2. Data models and architectures

3. Conversion between formats

4. Import/export utilities

5. Interacts with RDBMS (SQL Server, Oracle, etc…)

What is GIS?

● Analysis

1. Spatially aware data

2. Attribute and spatial query

3. Proximity and Overlay

4. Advanced geoprocessing techniques

5. Decision support

6. Flexible, customization

7. Programming, scripting (to perform analysis)

What is GIS?

● Visualization

1. Maps! Maps! Maps!

2. If a picture is worth a 1000 words…

3. Professional cartographic tool

4. Charts, graphs, tables, etc…

5. Various coordinate systems

6. 2D and 3D

7. Web, desktop, handheld, etc…

What is GIS?

● GIS uses maps to spatially analyze and search for patternsin the data that would otherwise not be found. (Content)

● GIS stores, manipulates, and displays data files andrelationships in a information system using standardcomputing practices. (IT)

● With advances in technology, GIS users must now deal withboth aspects!

“G” vs. “IS”

“G” = Geographic

● Denotes the concept of spatial location on Earth’s surface

● Importance of relative location (not just where you are butwhere you are in relation to everything else)

● Theories and techniques in Geography form the basis of GIS

The “G”?

“I” = Information

● Substance (knowledge) about location

● Factual and interpretative

● Tables + Maps + Analysis

● Transformation of table information into spatial context foranalysis

● Technology and computer systems

The “I”?

● Yes, it is used quite often.

● Commonly used as a replacement for or broadening of theterm “GIS data”

● But…

What about just “GI”?

● Science

● Systems

● Studies

● Services

What About the “S” in GIS?

System, science, study and service

Geographical information system

Emphasising infrastructure

Geographical information science

Emphasising principle and theory

Geographical information study

Emphasising data and data mining


Emphasising socio-economic service


GISystems

GIStudiesGIScience

GIServices

GIScience, GISystems and GIStudies

● GIScience – fundamental scientific issues arising from theuse of GISystems (concepts, techniques)

● GISystems – implement the storehouse of GIScienceknowledge (tools, techniques)

● GIStudies – how systems and science are embedded in asocietal context

● GIServices – basically the products/outcomes of the abovethree

● Understanding GIS requires consideration of science,systems and studies

● GIS provides a framework to manage the world

● The real value of GIS is its problem solving capability

● The future of GIS and GISci is bright

GIScience, GISystems and GIStudies

● Geographic + GIS = “Geospatial”

● Move in recent years to better define the industry and tofocus on data (business) over geographic principles(academic)

● Geospatial includes all subcomponents of GIS embedded inother areas (remote sensing, GPS etc.)

Geospatial?

● County Governments

● City Governments

● Local Utilities

● Police Departments

● Fire Departments

● School Districts

● Non-Profit Organizations and many more

● Anyone who is seeking a way to organize data and get answers.


● GIS technology is to geographical analysis what themicroscope, the telescope, and computers have been toother sciences.

● It integrates spatial information within a singlesystem.

● It allows us to manipulate and display geographicalknowledge in new and exciting ways.


● GIS gives a “high tech” feel to geographic information.

●Maps are fascinating and so are maps in computers.

● There is increasing interest in geography andgeographic education.

● GIS is an important tool in understanding and managingthe environment .

Why is GIS so HOT?

● It is the most advanced electronic tool for examining spatialinformation in an organized manner.

● Provides powerful tools for

- data process, analysis, and visualization

- data management and retrieval

● One of the fastest growing high-tech career fields

Why GIS?

- wider availability of GIS through the internet, as well asorganization-wide local area networks

- Reductions in the price of GIS hardware and software- Greater awareness of why decision-making has a

geographic dimension- Greater ease of user interaction, using standard

windowing environments- Better technology to support applications, specifically in

terms of visualization, Data management and analysis, andlinkage to other software

- The proliferation of geographically referenced digital data,such as GPS

- Availability of packaged applications-The accumulatedexperience of applications that work

Why GIS?

Why GIS?

GIS Challenges

Spatial information is important because “almost everything that happens,

happens somewhere. Knowing where something happens could be critically

important”(Longley et al. 2011). This sentence is important fore disaster

risk management to know which areas could be vulnerable to plan

prevention and response. For instance, One of the first use of maps to

do an spatial analysis was done by John Snow during cholera outbreak in

London (year 1854). John Snow used a map of London streets to study

cholera individual cases distribution. The map point to the source of the

decease, a water pump (see Fig. 1). “A picture tells a 1000 words”

Fig. 1. A variant of the original map drawn by Dr. John Snow (1813-1858), a British physician who is one of the founders of medical epidemiology, showing cases of cholera in the London epidemics of 1854, clustered around the locations of water pumps.


http://iidl.evai.net/iidl/cursos/GDRM01$$2013$$A/compartida/Pau/introductionGIS/IntroductionGIS.html#seqrefFig0

*it is multidimensional, at least two coordinates must be specified to define a location

*it is voluminous, can easily reach a terabyte in size*It must be projected onto a flat surface

*it requires many spatial methods for its analysis

*it can be time-consuming to integrate and analyze the many varied types of geographic information

*Although much geographic information is static, the process of updating is complex, and expensive

*Display of geographic information in the form of a map requires the retrieval of large amounts of data


Reasons why geographic information is special!

.....simply a computer system for making maps, although it can

create maps at different scales, in different projections, and

with different colors. A GIS is an analytical tool. The major

advantage of a GIS is that it allows you to identify the spatial

relationship between map features. A GIS does not store a

map in any conventional sense; nor does it store a particular

image or view of a geographic area. Instead, a GIS stores the

data from which you can draw a desired view to suit a

particular purpose.

GIS is not......

Technology diffusion

People oriented applications

Interactive and real-time applications

Cleverer and more comprehensive

To use GIS, or not to use?

The future of GIS

Image View

Map View

3D View

Street View

Get Direction

Everything has a location

Everyone is a Provider

Everyone is connected

And many more such as

weather station observations

water meter readings,

sampler analysis results,

daily sale amounts census

results ……..


● Published Paper Maps

● Aerial Photographs - Photogrammetric Mapping

● Satellite Imageries - LandSat, Spot, RADAR SAT etc.

● Global Positioning System (GPS) Survey

● Civil Surveying - Total Station, Plane Table survey

● Geodetic Survey – Bench Mark Datum Level

● Digital data from other organization


● Agriculture

● Archaeology

● Business

● Environment

● Geology

● Health

● Hydrology

● Land Information System

● Military

● Natural Hazard Management

● Natural Resource Management

● Urban Planning

● Many more ……

http://www.gisdevelopment.net/application/index.htm


Flood Depth

Inundation

Mapping

& Depth-Duration

Analysis

Analysis of

Morphological

Changes of

River Plan form

Topographic

Survey & Mapping

Digital Elevation

Model, Contour

Preparation

Interactive Geo-referenced Database,

Analyses, Presentation and Mapping

Major GIS

Applications

Water and

EnvironmentCrop Damage

Assessment

due to

Inundation

Based on

Satellite

Imageries

Environmental Impact

Assessment &

Salinity Mapping

Application

Development

Elevation in mPWD

Area Elevation Curve

Long Profile of River

Time Series Graphs

Real Time Flood Mapping based on Model Data

Cut / Fill and Conveyance Calculation

Landuse Changes over the period

DEM comparison

Cross Section Profile &

Comparison with previous Data

Interpretation of Satellite Imagery

Topographic Survey and Mapping

Digital Elevation Model (DEM), Contour & Bathymetry

Flood Inundation & Salinity Mapping


Core of GIS = “Layers”

● Geographic data = Representation of reality

● Reality is complex.

● GIS utilizes a layer approach

● Each layer only includes information about one type ofphenomenon.

● Data layers must be aligned with one another


Aerial

Photography

Land

Surveying

GPSWhat Where

Geographic

Information

Fields

Samples

Population

Census

Administrative

Records


● GIS is a convergence of technological fields andtraditional disciplines.

● GIS has been called an “Enabling Technology”.

● GIS is associated with other Major FollowingDisciplines:

● Geography

● Cartography

● Remote Sensing

● Photogrammetry

● Statistics

● Computer Science


● Broadly concerned with understanding the world andman’s place in it.

● Long tradition in spatial analysis.

● Provides techniques for conducting spatial analysis.

Geography

● Computer cartography provides methods for digitalrepresentation.

● It is concerned with the display of SpatialInformation.

● It provides long tradition in the design of maps whichis an important form of output from GIS.

Cartography

● Remote Sensing includes techniques for dataacquisition and processing anywhere on the globe at lowcost.

● Images from space and the air are major source ofgeographical data.

● Interpreted data from a remote sensing system can bemerged with other data layers in a GIS

Remote Sensing

● Photogrammetry is the source of most data used forinput to GIS.

● In Photogrammetry we use aerial photography formaking measurements.

Photogrammetry

● Statistics is important in understanding issues of errorand uncertainty in GIS data.

●Many models are built using GIS are statistical innature.

●Many statistical techniques are used for analysis.

Statistics

● CAD provides software, techniques for data input,display and visualization.

● Advances in computer graphics provide hardware,software for handling and displaying graphic objects.

● DBMS contribute procedures for system design andhandling large volume of data.

Computer Science

● Data Processing System

● Data Analysis Subsystem

● Information User Subsystem

GIS as a set of Integrated Subsystem

● Data Acquisition : from maps, images or field surveys.

● Data Input : data must be input from source materialto the digital database.

● Data Storage : how often is it used, how should it beupdated, is it confidential?

Data Processing Subsystem

● Retrieval and Analysis : may be simple responses toqueries, or complex statistical analysis of large sets ofdata.

● Information Output : how to display the results? Asmaps or tables? Or will the information be fed intosome other digital system ?

Data Analysis Subsystem

● Users may be researchers, planners, managers

● It provides interaction between GIS group and usersto plan analytical procedures and data structures.

Information User Subsystem

Data from Maps

Tabular data

Field data

Data from other

digital database

Remote sensing

Global positioning

system

Reports

Maps

Photographic

products

Statistics

To other digital

database

Input to Models

Geographic Information System

Database Management

Ideal GIS

Power of GIS - Integration

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Topics Covered by this Presentation

ArcGIS views Data Management – Database View

Analysis – Model View

Visualization – Map View




Why is GIS so HOT?

GIS Challenges


GIS is not......

The future of GIS



60

Topics Covered by this Presentation







Ideal GIS

What We Learnt

Understanding of GIS, its application, its fundamentals

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What Next?

Lecture 08 - 14:Fundamentals of GIS

lecture 04 - 07: introduction to gis · understanding gis requires consideration of science,...

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