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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