INTRODUCTION TO GEOGRAPHIC INFORMATION SYSTEMS (GIS)

What is GIS?

A GIS integrate hardware, software and data for capturing, managing, analysing and displaying all forms of geographically referenced information.

A Geographic Information System (GIS) is a computer-based system including software, hardware, people, and geographic information.

A GIS can: create, edit, query, analyze, and display map information on the

computer.

Geographic Information System

Geographic – 80% of government data collected is associated with some location in space

Information - attributes, or thecharacteristics (data), can be used to symbolize and provide further insight into a given location

System – a seamless operation linking the information to the geography – which requires hardware, networks, software, data, and operational procedures

…not just software! …not just for making maps!

Homes School Districts Streets Zip Codes Cities Counties

CAPTURE

STORE

QUERY

ANALYZE

DISPLAY

OUTPUT

GIS FUNCTIONS

Capturing Data: A GIS must provide methods for inputting geographic (coordinate) or tabular (attribute) data. The more input methods available, the more versatile the GIS.

Storing Data: There are two basic data models for geographic data storage: vector and raster. A GIS should be able to store geographic data in both models.

Querying data: A GIS must provide utilities for finding specific features based on location or attribute value.

Analyzing data: A GIS must be able to answer questions regarding the interaction of spatial relationships between multiple data sets.

Displaying Data: A GIS must have tools for visualizing geographic features using a variety of symbology.

Output: A GIS must be able to display results in a variety of formats, such as maps, reports, and graphs.

COMPONENTS OF GIS

People: This is the most important component in a GIS. People must develop the procedures and define the tasks of the GIS. People can often overcome shortcomings in other components of the GIS, but the best software and computers in the world cannot compensate for the incompetence of people.

Data: The availability and accuracy of data can affect the results of any query or analysis.

Hardware: hardware capabilities affect processing speed, ease of use, and the type of output.

Software: This includes not only actual GIS software, but also various database, drawing, statistical, imaging, or other software.

Procedures or Methods: Analysis requires well-defined, consistent methods to produce accurate, reproducible results.

HOW GIS WORKS

Thematicobjectselection

Real world

Maps

-Analysis

GIS operations

Cartographicprocessing

.- Generalization- Symbolization

Geology

Hydrology

Soil

Attribute tables

Decision makers

Statistical tablesGPS Satellite imagesAerial photographs

Point

Area

Line

Field Survey

GIS WORKFLOW

DATA IN GIS

Spatial and Attribute dataThere are two important components of geographic database: its geographic position and its attributes or properties. In other words, spatial data (where is it?) and attribute data (what is it?)

SPATIAL DATA

City blocks Land use

001 Institutional 002 Commercial 003 Commercial 004 Residential 005 Residential 006 Residential 007 Industrial 008 Residential 009 Industrial 010 Industrial 011 Residential 012 Industrial 013 Residential 014 Residential 015 Residential

Map: City blocks

ATTRIBUTE DATA

SPATIAL AND ATTRIBUTE DATA

What makes data spatial?

PlacenameGrid co-ordinate

Postcode

Distance & bearingDescription

Latitude / Longitude

Characteristics of spatial data

Location

Description: University of Azad Jammu and Kashmir Post Code: 13100 Latitude/Longitude: 33° 21’ 55.38”N, 73° 36’ 17.62”E

Characteristics of spatial data

Geometry The shape of a

building or county The course of a

river, the route of a road

The shape of the landscape, relief

Maps model the real world with points, lines, and polygons. Symbols and labels describe the descriptive information about the geographic features.

PointsPoints define the discrete locations of geographic features which are too small to illustrate as lines or polygons such as well or telephone poles. Points can be used to illustrate the locations of mountain peak or discrete elevation points.

LinesLines represent the linear features of geographic object too narrow to illustrate as polygons, such as streets and streams that have length but no area. Moreover, contour lines are represented as the lines

By using different symbols and labels, descriptive information of linear features are illustrated. For example: Roads are drawn with various line widths and patterns and colors to represent different road types, e.g., highway as wide solid red colour line, blue lines are used to illustrate the streams. The symbol can be used to illustrate the railway.

City streets are labeled with names and often address ranges.

BASIC TYPES OF SPATIAL DATA

PolygonsPolygons are closed features that represent the shape and location of homogeneous features such as landuse, forest types. Tone of the colour can be applied to illustrate the density of population, green color can be used to represent vegetation and blue colour can be used to illustrate lake.

SurfacesA surface represents the elevation, presence or absence of something for every point on the piece of earth. The elevation models are best examples to illustrate as the surfaces.

Surfaces are typically represented on the maps as the series of isolines. Elevation contours, rainfall, temperature can be represented as the surface of isolines.

Surfaces can be represented as the Raster Elevation Model and Vector Elevation Model.

Point Line

Areasurface

GEOMETRY OF SPATIAL DATA

Vector Graphics: •Images are built-up from points, lines (segments) and areas (Polygons). •Each defined by pair of X-Y co-ordinates.•Preparing a map by digitization is converted into vector data in computer.

Raster Graphics: •Images are built-up from cells which is called as Pixels.•In raster graphics, the smaller the area of land that each cell represents, the higher the resolution of the data and higher the spatial accuracy, ultimately the larger the files needed to store the data..For continuous data such as elevation, slope, surfaces.

REPRESENTATION OF GEOGRAPHIC DATA

VECTOR AND RASTER REPRESENTATION

Raster

Vector

Real World

VECTOR AND RASTER REPRESENTATION

GIS LAYER A GIS stores information

about the world as a collection of layers that can be linked together by geography.

Real World

Why do we need GIS?

Because location is important, It is an issue in many of the problems society must solve. Problems that involve an aspect of location, either in the information used to solve them, or in the solutions themselves, are termed geographic problems.

Examples of geographic problems

Health care managers solve geographic problems “Where to locate new clinics and hospitals”

Delivery companies solve geographic problems when they decide the routes, and schedules of their vehicles, often on a daily basis.

Transportation authorities solve geographic problems “When they select routes for new highways”

Forestry companies: They determine how best to manage forests, etc.

Governments solve geographic problems when they decide how to allocate funds for building sea defenses

APPLICATIONS OF GIS

Applications generally fulfill the five M’s of GIS: mapping, measurement, monitoring, modeling, and management

APPLICATIONS OF GIS

· land-use planning and management · oil & mineral exploration · environmental impact studies· management of water resources· natural hazard mapping · forestry and wildlife management · soil degradation studies · agricultural development· socio-economic survey and mapping · Measurements of landscapes or structures · Transport/vehicle routing

and many more . . .

INTRODUCTION TO ArcGIS SOFTWARE

ArcGIS is a Product of

ESRIENVIRONMENTAL SYSTEM RESEARCH INSTITUTE

It is available in three license level………. Basic, ArcView Standard, ArcEditor Advanced, ArcInfo

ArcGIS Desktop Software

Exploring ArcGIS Desktop

ArcView: viewing, map production, spatial analysis, basic editing

ArcEditor: ArcView, plus specialized editing

ArcInfo: ArcView & ArcEditor plus special analysis and conversions

• All three software products look and work the same. They differ only in how much they can do.

• ArcEditor does more than ArcView, and ArcInfo does more than ArcEditor.

ArcInfo is now referred to as ArcGIS for Desktop Advanced

ArcInfo

Mapping & Analysis for Understanding Our World

ArcGIS DesktopVersion 10.1

ArcMap

Mapping, editing, analysis

ArcCatalog

Manage spatial data, database designs, creation and management of metadata

ArcToolbox

GIS data conversion and geoprocessing

ArcScene3-D display

.

Main components of ArcGIS

Powerful map creation and spatial data editing.

ArcMap is the main interface for conducting analysis and creating maps. Here, feature classes and shapefiles can be populated, data can be edited, calculations can be performed, and finally, maps can be created for displaying the results of the GIS analysis

ArcMap

Open Arc Map

Tool Bar

DISPLAY WINDOW

ArcCatalog

Arc Tool Box