Geographic Information Geographic Information Systems (GIS)Systems (GIS)

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PresentationPresentation OrganisationOrganisation

1.1. Conventional Ways to Store DataConventional Ways to Store Data•• DatabasesDatabases•• MapsMaps•• Databases Vs MapsDatabases Vs Maps

2.2. What is GIS?What is GIS?3.3. GIS InputsGIS Inputs4.4. Mapping Through GISMapping Through GIS

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1.1.Conventional Ways to Store DataConventional Ways to Store Data

DATABASESDATABASES

A collection of data arranged for case & speed of search and retrieved is called data bank. It is one or more structured sets of persistent data, usually associated with software to update and query the data. A simple database might be a single file containing many records or it comprises tables having fields with specific data structure. The tables are linked with each other through various common fields in these tables. It is a logical collection of interrelated information, managed and stored as a unit, usually on some form of mass storage system such as magnetic tape or disc. A database is one component of a database management system.

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Conventional Ways to Store DataConventional Ways to Store Data

MAPSMAPS

“An abstract representation of the physical features of a portion of the earth’s surface graphically displayed on a planar surface. Maps display signs, symbols and spatial relationship among the features” or “A Facility for displaying interpretation of geographic information on a flat surface.” Location information describes the position of a particular geographic feature on earth's surface & provides the basis for representing spatial relationships between these features.The relationship that exist between a distance on a map and the corresponding distance on the earth. It may be expressed as an equivalence, one inch equals 16 statute miles; as a fraction or ratio, 1:1, 1,000,000; or as a bar graph subdivided to show the distance that each of its parts represents on earth.

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Conventional Ways to Store DataConventional Ways to Store Data

DATABASES Vs MAPSDATABASES Vs MAPS

Strong Point:

Very good for Searching

Weak Point:Bad for visual Interpretation

Strong Point:

Very good for visual Interpretation

Weak Point:Bad for searching

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WHAT IFWHAT IFTHE TWOTHE TWO

COULD BE COULD BE LINKED?LINKED?

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2.2.What is GIS?What is GIS?

The automated Searching The automated Searching

of a conventional of a conventional

database gets Visual database gets Visual

Interpretation through its Interpretation through its

connectivity with Map!connectivity with Map!

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THAT’S WHAT WE CALLTHAT’S WHAT WE CALL

GEOGRAPHIC INFORMATION GEOGRAPHIC INFORMATION SYSTEM (GIS)SYSTEM (GIS)

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DEFINITIONDEFINITION

GIS is a computer system capable of assembling, storing,

manipulating and displaying geographically referenced information

i.e. data identified according to their locations. Practitioners also

regard that total GIS includes operating personnel and the data that

goes into the system.

GeographicInformationTechnology

GIS GIS -- TodayToday SUPARCO

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GIS InputsGIS Inputs

•• Survey MapsSurvey Maps

•• Remote Sensing DataRemote Sensing Data

•• Field Sampling DataField Sampling Data

•• Statistical DataStatistical Data

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GIS InputsGIS InputsSURVEY MAPSSURVEY MAPS

• The term map refers to a

data set which contains accurate information about features on the surface of Earth

• Map data have two principal components: geometrygeometry and attributes attributes (annotations)

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GISGIS InputsInputsREMOTE SENSING DATAREMOTE SENSING DATA

In order to produce map from satellite image it is necessary to

•Define the geometry of the image

• It must be converted into a suitable GIS format

• The theme be selected in which the end user is interested

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GIS InputsGIS Inputs

FIELD SAMPLING DATAFIELD SAMPLING DATA

• GIS is a versatile tool, its main potential lies in its data analysis

capability

• Only the map data are not sufficient for analysis purposes

•Attribute data are also included in a GIS based study / project to

make it a more smart and intelligent system

• Field Sampling data are also a part of GIS that makes the GIS

based study more meaningful and authentic

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GIS InputsGIS Inputs

SOURCES OF FIELD SAMPLING DATASOURCES OF FIELD SAMPLING DATA

• Global Positioning System (GPS) is most widely used for collecting

field data. It not only gives accurate position measurements but is

also a good source for attribute data collection

• Conventional survey data can also be incorporated in a GIS

database like; soil survey data including pH, phosphorous,

potassium, electrical conductivity etc. to make the database more

useful

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GIS InputsGIS InputsSTATISTICAL DATASTATISTICAL DATA

GIS analytical capabilities can also be used to analyse Statistical data like:

• Demographic Data

• Education & Health

• Agricultural Data

• Gross National Product (GNP)

• Gross Domestic Product (GDP)

• Census Record

• Hydrological Data

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INPUTSSurvey MapsRemote Sensing DataField Sampling Data

Statistical Data

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4.4.Mapping through GISMapping through GIS

The information conveyed by a map can be said to be represented

graphically as a set of map components. Location information on a

map is represented by:

• Points, for features such as site locations or electric poles

• Lines, for features such as streams, roads or contour lines

• Areas, for features such as lakes, political boundaries or soil units

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Mapping through GISMapping through GIS

POINT FEATURE

A point feature is represented by a single location that defines a map object whose boundary or shape is too small to be represented by a line or an area. A special symbol or label often depicts a point location.

LINE FEATURE

A line feature is a set of ordered coordinates which connect to represent the linear shape of a map object that is too narrow to be displayed as an area. Or, it could be a feature which has no width such as a contour line.

AREA FEATURE

An area feature is described by a closed boundary which encloses a homogenous area, such as a lake or a park.

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Mapping through GISMapping through GISGRAPHIC ELEMENTSGRAPHIC ELEMENTS

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Mapping through GISMapping through GIS

MAP SCALEMAP SCALE

Map scale is the extent of reduction required to display a portion of

the earth's surface on a map. It is expressed as a ratio of the

distance on the map page to the distance on the ground.

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Thank YouThank You