A geographic information system (GIS) is a computer system for capturing, storing, analyzing and displaying spatial data. It allows users to create interactive queries (spatial data analysis) and maps from a variety of sources. GIS technologies include mapping software and its application with remote sensing, land surveying, aerial photography. Some key uses of GIS are in telecommunications network planning, environmental impact analysis, urban planning, agriculture, and regional planning.

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GEO 21653
GPS
01.What is a GIS?
A geographic information system is a computer system for capturing,
storing, checking and displaying data related to positions on earth’s surface. An
information system that deals with spatial information. It also called "mapping software"
It is a system that creates, manages, analysis and maps all types of data. GIS
Technology is a crucial part of spatial data infrastructure, which the White house define as
“the technology, policies, standards, human resources and related activities necessary to
acquire, process, distribute, use, maintain and preserve spatial data. A GIS is used in a variety
of applications, including exploration, demographics, dispatching, tracking and map making.
GIS has a Data base Function. There are,
➢ Data capturing
➢ Data storing
➢ Data retrieving
➢ Data updating
➢ Data manipulating
➢ Data transforming
➢ Data analysis
➢ Data display

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Compenets of
GIS
Data
Users
SOFTWARE
Hardware
Components of GIS
02.Why useful Georeferencing?
Georeferencing is the process of taking a digital image, it could be an air photo,
scanned geologic map or a picture of a picture of a topographic map and adding geographic
information to the image so that GIS can place the image in its appropriate real-world
location. It is crucial to make aerial and satellite imagery, usually raster images ,useful for
mapping as it explain how other data such as the above GPS points ,relate to the imagery.
Very essential information may be contained in data or images that were produced at a
different point of time. Georeferencing in the digital file allows basic map analysis to be
done, such as pointing and clicking on the map to determine the coordinates of appoint to
calculate distances and areas and to determine other information .
Once a feature has been georeferenced, it can be used in spatial analysis and mapping
application. This process can be used to improve the accuracy of digital maps or make
existing maps compatible with new data. It also mean using a map and referencing it via GPS
or other sources of position information and then recording the values of these coordinates to
a database.
03.How GPS system work?
The Global Positioning System (GPS) is a satellite
constellation supporting highly accurate positioning, navigation and timing measurements
worldwide. As one of the first satellite positioning systems, GPS has become integral to work
done worldwide, For examples, Precision agriculture, autonomous vehicles, marine or aerial
surveying and define applications. It is a satellite based system consisting of a minimum of
24 satellites. It works 24*7 across the global regardless of the weather conditions. There is

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also not set up charges for use it. GPS also often used to describe the positioning system itself
for our lives.
GPS includes three main segments:
• Space segment(satellite) – They serve like stars in the constellation.
• Control segment (Ground station) -They monitor and control satellites.
• User segment -Receivers are constantly listening for signals from the
satellite.
Doppler effect is the fundamental principle used in GPS ,Changes in signal
frequency from the GPS satellites it helps determining to location and speed. Any instant of
time, there are at least 4 GPS satellites in line of sight to a receiver on the earth. Each of
these GPS satellites sends to information about its position and the current time to the GPS
receiver at fixed regular instants of time.
This information is transmitted to the receiver in the form of signal
which is then intercepted by the receiver to devices. These signals are radio signals that
travel with the speed of light. The distance between a GPS receiver and the satellite is
calculated by finding the difference between the time the signal was sent from GPS satellite
and the time the GPS receiver received for the signal. Once the receiver receives the signal
from at least three satellites, the receiver then points its location using trilateration process.
A GPS requires at least 3 satellites to calculate 2-D position (latitude and longitude on a
map).

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Control segment
Satellite
Receiver segment

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04.Make your area of interest using google earth?

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05.Do georeferencing to above area of interesting using QGIS?

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06.Add at least another adjacent 3 images above map.
Map 01
Map 02

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Map 03
07.Why GPS want to prepare GIS Map?
Because GIS is a computer system designed to capture, store, manipulate,
analysis manage and present a variety of spatial and geographical data. This computer system
is very important especially when it comes to planning . It has been used in variety of
industries to help in planning and monitoring.
❖ It is used in planning, collecting, analysing, and stringing the complex network
designs that are needed to come up with a working architecture in the field of telecom.
❖ GIS plays an important role in the environmental impact analysis process.
❖ Urban planning is one of the importance of a GIS .it can be analysing the urban
growth and direction during expansion.
❖ GIS helps to analysis environmental impact process.
❖ It can be used to plan what crops needs to be grown in what areas of the farm
depending on the soil structure and soil composition.
❖ The data can provide insights that can help inform the planning of the community
land based on the need of the community.

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❖ GIS can also provide important data that can be used for important data that can be
use regional planning.
❖ GIS is instrumental in providing information on space utilization.
08. What are the raster and vector?
RASTER
o In its simplest form a raster consists of matrix of cells organized into rows and
columns where each cell contains a value representing information ,such as
temperature. These are the types of images that are produced when scanning or
photographing an object.
VECTOR
o Vector graphics are computer images created using a sequence of commands
of mathematical statements that place lines and shape in a two dimensional or
three dimensional space.
 A graphic artist’s workor file is createdhadsaved as a sequence of vector
statements