Geographical information system

Presentation on
Geographical Information System
Presented by
Bipin Karki
Agriculture Instructor
Sarba Secondary School

Geographical Information System
• A geographical information system is a system designed to capture, store,
manipulate, analyze, manage and present spatial or geographic data.
• GIS applications are tools that allow users to create interactive queries, analyze
spatial information, edit data in maps and present the results of all these
operations.
• GIS can refer to a number of different technologies, processes, techniques and
methods. It is attached to many operations and has many applications related to
engineering, planning, management, transport, insurance, telecommunication
and business.

GIS
An automated system for ......
• Capturing
• Storing
• Retrieving
• Analyzing and
• Displaying
geographically-defined (spatial) data.

Geospatial Information
information about places on the earth’s surface
knowledge about “what is & where when”
(Don’t forget time!)
GIS--what’s in the S?
Systems: the technology
Science: the concepts and theory
Studies: the societal context

GI Systems, Science and Studies
Which will we do?
Systems
technology for the acquisition and management of spatial information
Science
comprehending the underlying conceptual issues of representing data and processes in
space-time
the theory and concepts behind the technology
Introduce enough of the science to apply the systems correctly and understand their
capabilities and limitations
Studies
understanding the social, legal and ethical issues associated with the application of GISy
and GISc
Discuss societal implications primarily in GISC (GIS Management and Implementation).

Geographical Information Technologies
Global Positioning Systems (GPS)
a system of earth-orbiting satellites which can provide precise (100 meter to sub-cm.)
location on the earth’s surface (in lat/long coordinates or equiv.)
Remote Sensing (RS)
use of satellites or aircraft to capture information about the earth’s surface
Digital ortho images a key product (map accurate digital photos)
Geographic Information Systems (GISy)
Software systems with capability for input, storage, manipulation/analysis and
output/display of geographic (spatial) information
• GPS and RS are sources of input data for a GISy.
• A GISy provides for storing and manipulating GPS and RS data

Scope and importance
• GIS in Education
GIS used in multiple disciplines: Agriculture, Archaeology,
Architecture/Landscape, Business, Computer Science Environmental
Science, Engineering, Journalism, Military Science, Natural Resource
Management, Geography, Geology Meteorology, Oceanography, Law
Enforcement, Public Health, History, Sociology Urban/Regional
Planning.
• Agriculture
-Farm management – Water management – Pest/Disease tracking –Crop
monitoring – Yield prediction – Soil analysis

• Natural Resource Management
Forestry -Ecology - Mining -Petroleum -Water Resources
• Planning and Economic Development
Land Use/Zoning -Emergency Preparedness - Population Forecast -Market Analysis
- Property Tax Assessment -Transportation
• Military and defense
-Battlefield management
-Satellite imagery interpretation
GIS: A Framework for Understanding and Managing Our Earth

• businesses
Use GIS for a very wide array of applications
‾ retail site selection & customer analysis
‾ logistics: vehicle tracking & routing
‾ natural resource exploration (petroleum, etc.)
• 80% of local government activities estimated to be geographically
based
‾ zoning, public works (streets, water supply, sewers), garbage
collection, land ownership and valuation, public safety (fire and
police)
• scientific research employs GIS
‾ geography, geology, Soil, botany, fishery
‾ anthropology, sociology, economics, political science
‾ Epidemiology, criminology

• Local Government
-Public works/infrastructure management (roads, water, sewer)
-Planning and environmental management
-property records and appraisal
• Real Estate and Marketing
-Retail site selection, site evaluation
• Public safety and defense
-Crime analysis, fire prevention, emergency management, military/defense
• Natural resource exploration/extraction
-Petroleum, minerals, quarrying
• Transportation
-Airline route planning, transportation planning/modeling
• Public health and epidemiology
• The Geospatial Industry
-Data development, application development, programming

Components of GIS
• Hardware
• Software
• Data
• People
• Methods

Hardware
• Hardware is computer on which GIS software runs.Nowadays there
are a different range of computer,it might be Desktop or server based.
• ArcGIS server is server based computer where GIS software runs on
network computer or cloud based.
• Components of hardware are:Motherboard(major hardware parts are
installed in it), Harddrive, Processor(CPU), RAM, Printer, External
Disk, Monitor

Software
• It provides tools to run and edit spatial information.
• It helps to query, edit, run and display GIS data.
• It uses
• Relational Database Management System to store data.
• Few software list are : ArcGis, ArcView, QQIS, SAGA GIS
Software components:
GIS tools(tools for browsing data), RDBMS(store data), Query tools(works
with RDBMS for querying, insertion, deletion, and Standard query
language), GUI(Graphical User Interface that helps user and software to
interact well), Layout(good layout windows to design map)

Data
• Data is the most important component of GIS. It is fuel of GIS.
• It is the combination of graphic and tabular data. Graphic can be vector
or raster.
• Both type of data can be created in house using GIS software or can be
purchased.
• The process of creating data from analog data or paper format is called
digitalization.
• Digitalization process involves registering of raster image using few
GCP(Ground Control Point) Or known coordinates. This process is
widely known as rubber sheeting or geo-referencing.
• Polygons, Lines and image are created by digitalizing raster image.

GIS data types
• Raster: Raster image store information in a cell based manner. It can
be aerial, photo, Satellite image, Digital elevation model.
Raster images normally store continuous data.
• Vector: Vector data are discrete. It stores information in x,y coordinate
format. There are 3 types of vector data: Lines, Points and area.

Peoples
• Users of GIS. Broadly 2 classes:
1. CAD/GIS operator: whose object is to vectorize map objects.
2. GIS Engineer: Who query and analyze works.
• They run the GIS software.
• Hardware and software have seen tremendous development which
made people easy to run the GIS software. Computer are affordable
so people are using it for GIS task.

Methods
• For successful GIS operation, Well designed plan and business
operations rules are important.
• Methods vary with different organizations.
• Organizations document their process plan for GIS operation. These
document address number question about GIS methods: No. of GIS
experts required, GIS software and hardware, Process to store the data,
type of DBMS and more.
• Map creation can be done by :
1. Automated raster
2. Vector Creator
3. Manually vectorised
4. Survey agency

GIS mapping
Components of maps
Scale
Used to show a portion of Earth's surface on earth
Small scale-1:1000000 Medium scale-1:175000 to 1:1000000 Large scale-
1:175000
Map resolution
Refers to how accurately the location and shape of map features can be
depicted for a given map scale. As map scale decreases, map resolution
decreases.
Map accuracy
Covers quality of source data, map scale, drafting skills and width of lines
on ground

GIS terminologies
• Attribute - A characteristic of a geographic feature, typically stored in
tabular format and linked to the feature in a relational database. The
attributes of a well-represented point might include an identification
number, address, and type.
• Base Layer - A primary layer for spatial reference, upon which other
layers are built. Examples of a base layer typically used are either the
parcels, or street centerlines.
• Buffer - A zone of a specified distance around a feature.
• Computer Aided Design (CAD) - An automated system for the design,
drafting and display of graphically oriented information.
• Database - A logical collection of interrelated information, managed
and stored as a unit. A GIS database includes data about the spatial
location and shape of geographic features recorded as points, lines, and
polygons as well as their attributes.

Digital Elevation Model (DEM) - Terrain elevation data provided in
digital form.
Digitize - To encode map features as x,y coordinates in digital form. Lines
are traced to define their shapes. This can be accomplished either manually
or by use of a scanner.
Geocode - The process of identifying a location by one or more attributes
from a base layer.
Layer - A logical set of thematic data described and stored in a map library.
Layers act as digital transparencies that can be laid atop one another for
viewing or spatial analysis.
Line – Lines represent geographic features too narrow to be displayed as
an area at a given scale, such as contours, street centerlines, or streams.

Metadata – Information about a data set. It may include the source of the data;
its creation date and format; its projection, scale, resolution, and accuracy; and
its reliability with regard to some standard.
Ortho Imagery - Aerial photographs that have been rectified to produce an
accurate image of the Earth by removing tilt and relief displacements, which
occurred when the photo was taken.
Point – A single x,y coordinate that represents a geographic feature too small to
be displayed as a line or area at that scale.
Polygon - A multisided figure that represents area on a map. Polygons have
attributes that describe the geographic feature they represent.
Scale – The ratio or relationship between a distance or area on a map and the
corresponding distance or area on the ground.
Spatial Analysis - The process of modeling, examining, and interpreting model
results. Spatial analysis is useful for evaluating suitability and capability, for
estimating and predicting, and for interpreting and understanding.

Structured Query Language (SQL) - A syntax for defining and manipulating
data from a relational database. Developed by IBM in the 1970s, it has become an
industry standard for query languages in most relational database management
systems.
Theme – An ArcView theme stores map features as primary features (such as
arcs, nodes, polygons, and points) and secondary features such as tics, map
extent, links, and annotation. A theme usually represents a single geographic
layer, such as soils, roads, or land use.
Base station: [surveying] A base station is a precisely surveyed location used as a
fixed Global Navigation Satellite System (GNSS) recording station. Base stations
are typically used in differential correction.
Bearing: [surveying] A bearing is a direction expressed as a geographic angle
measured from a base line used in surveying and navigation

Benchmark: [surveying] Benchmarks are precisely surveyed points
usually marked with a brass or metal disk in the ground. Benchmarks is a
generic term sometimes referred as survey marks, geodetic marks and
control stations.
GDAL: [GIS software] Geospatial Data Abstraction Library (GDAL) is a
C++ library for reading and writing raster geospatial data formats,
implementing common GIS operations (unions, intersections, joins,
clipping, etc.) with command line utilities. It supports old hardware and
operating systems and requires very low amounts of memory.
Generalization Tool: [GIS processing] The Generalization Tool is an
editing process that simplifies the shapes and edges of linear or polygon
features in a map. Using an offset tolerance, the output will reduce the
number of vertices used in the line or polygon.

Geocoding: [GIS processing] Geocoding is the process of assigning geographic coordinates
to places based on street address, town/city, province/state and country.
Arc: [data structure] Arcs are lines or polygon boundaries, represented as a series of
vertices or coordinate points.
ArcGIS: [software] ArcGIS is a GIS software package produced by the Environmental
Systems Research Institute (Esri) which allows you to collect, store, manage, visualize,
export, analyze and map geographic data. ArcGIS is a suite of spatial analysis tools and
cartographic features on a customizable user interface that allows you to be understand and
make decisions with spatial data.
ArcGlobe: [software] ArcGlobe is a global three-dimensional visualization and analysis
environment as part of the Esri ArcGIS suite (3D analyst), specializing in global datasets
and larger study areas.
Aspect: [GIS processing] Aspect is the slope direction on a terrain surface. Aspect is
measured clockwise starting North as 0° to 360° North again with flat areas given a value of
-1 (or 0 degrees).

Geographical information system

Geographical information system

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Geographical information system