fundamentals in gis...the world expressed in a gis database. a model is a representation of a...
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Data and Information
What is an Information System?
Information systems can be very simple, such as atelephone directory.
DataStorage
Information System
QueryInformation
* System is the technology used
Entering into GEO – practical way
Existence and sustenance is always a key challenge to Humans
Evolution was all about knowing and
Gaining knowledge of surroundings
Identifying and locating.
Questioning the behavior.
Analysing by experimenting.
Track changes over time.
Share the observations.
Making Decisions that change the world into a better place to live.
Wisdom + Technology = Innovation
Information systems help us to manage what we know, by making easy to organise and store, access
and retrieve, manipulate and synthesize, and apply knowledge to the solution of problems.
• Geographic/ Geospatial Information
information about places on the earth’s surface
knowledge about “what is - where - when” (Don’t forget time!)
Geographic/geospatial: synonymous
• A Geographic Information System is not only about computers, software and electronic data.
A GIS is an organised collection of :– Hardware– Software– Network– Data– Procedures– And people!
Geographic Information Systems - Popular definitions
A system of integrated computer-based tools for end-to-end processing (capture,
storage, retrieval, analysis, display) of data using location on the earth’s surface for
interrelation in support of operations management, decision making, and science.
A system of integrated computer-based tools for end-to-end processing (capture,
storage, retrieval, analysis, display) of data using location on the earth’s surface for
interrelation in support of operations management, decision making, and science.
convergence of technology and traditional disciplines.convergence of technology and traditional disciplines.
GIS
ComputersGeography
Applications
The World
GeographicKnowledge
Citizens
Inventory
Decision Support
DataInformation
ModelAnalyseShare
Decision
Output
GISanalysis
Import orbuild datasets
Define GIScriteria
DefineproblemDecision
GISA Systematic Cyclic ProcessOutput
GISanalysis
Import orbuild datasets
Define GIScriteria
Defineproblem
Geographic Information SystemsGeographic Information Systems
• The possibilities are unlimited…– Facility Mapping
– Natural Resources Management
– Decision Support systems
– Disaster management
– Environmental impact assessment
– Land use planning
– Tax Mapping
– Water and Sanitation Mapping
– Transportation routing
– and more ...
Problem on Earth – Deal it with GIS ( Almost )
What can you do with a GIS?
Why Study GIS?
• Most of Government activities estimated to be geographically based
( E-governance )
– plots, zoning, public works (streets, water supply, sewers), garbage collection, land ownership and
valuation, public safety (fire and police)
• A significant portion of Government has a geographical component
– natural resource management, highways and transportation
• Businesses use GIS for a very wide array of applications
– retail site selection & customer analysis, logistics: vehicle tracking & routing
• Military and defense– Battlefield management
– Satellite imagery interpretation
• Scientific research employs GIS
– geography, geology, botany
– anthropology, sociology, economics, political science
– Epidemiology, criminology
Examples of Applied GIS
• Urban Planning, Management & Policy
– Land acquisition
– Economic development
– Emergency response
– Tax assessment
• Environmental Sciences
– Management of watersheds,
floodplains, wetlands, forests, aquifers
– Environmental Impact Analysis
– Groundwater modeling and
contamination tracking
• Political Science
– Analysis of election results
– Predictive modeling
• Business
– Demographic Analysis
– Market Penetration/ Share Analysis
– Site Selection
• Real Estate
– Neighborhood land prices
– Traffic Impact Analysis
– Determination of Highest and Best Use
• Health Care
– Epidemiology
– Needs Analysis
– Service Inventory
Functions of a GISData Collection
ModelingStatistical AnalysisOverlayingBuffer Analysis
Data Analysis
Field dataSatellite dataArial PhotosAnalog MapsReports
ReclassificationScale ChangeRegistrationLine Smoothening
Data Manipulation
ImagesGraphsMapsTablesASCI Files
Data Display
Creation ofdatabase
Data Storage
Components of gisData types and representationGeometry, accuracies etc
Analysis – buffering, models, topology
Representation styling , pdfs etcDecision making
modeling and simulationDissemination
web, reportsOntology, emerging trendsApplications
Geographic Information Technologies
• Global Positioning Systems (GPS) - Input Data Source
– 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) - Input Data Source
– 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) – Storage and Analysis
– Software systems with capability for input, storage, manipulation/analysis and output/display of
geographic (spatial) information
• GIS—Sub Systems with ‘S’
Systems: Technology for acquisition and Management
Science: Conceptual issues of representing data and processes in space-time
Studies: Understanding the social, legal and ethical issues associated
GIS Components
1. Data Input1. Data Input
3. Query Input3. Query Input 2. GeographicDatabase
2. GeographicDatabase
4. Display andReporting
5. Transformationand Analysis
6. Decision Support /Problem Resolution
7. Dissemination(Reports, Pdf, Maps, Web)
Data
• Raw facts/details• Geo-spatial Data
– Physical/Topographic– Thematic/Derived– Auxillary/Attributes
The Data
Data is organized by layers, coverages or themes (synonomous concepts), with each layer
representing a common feature.
Layers are integrated using explicit location on the earth’s surface, thus geographic
location is the organizing principal.
GIS works mainly with two data models – Raster & Vector
A. Raster Model
Represents area covered by grid with (usually) equal-sized, square cells
Each grid or cell has one unique value representing the attribute or
feature.
Usually satellite or areal imagery is represented in Raster data format.
Data formats like GeoTIFF, img, pix, hdf are used.
A. Vector Model
Represents area covered with geographic features.
points or dots (nodes): trees, poles, fire plugs, airports, cities
lines (arcs): streams, streets, sewers,
areas (polygons): land parcels, cities, counties, forest, rock type
Attributes are represented in tables.
Data formats can be shp, gml, kml or from RDBMS like postgres, oracle,
mysql etc.
Data Structures - Geospatial
Data Structures : Raster
Raster dataset attribute table
Data Structures : Raster
• Types
Continuous Thematic
Data Structures : Raster
Data Structures : Vector
Primitive Features
Points
Lines / Arcs
Polygons
► Geometry primitives of vector data model
are
Point, Line and Polygon
objects can be built from these
primitives
► Object location determined by represented
location point
► Uniqueness of vector data model lies in its
management and storage of data geometry
primitives
► Origin for vector data is lower left corner
Point
Line /Arc
Polygon/ Area
VECTOR RASTER
Data Structures
Data Structures : Vector
Topological Model
◦ Where is it? (location)
◦ What is next to (adjacency)
◦ Is it inside or outside (containment)
◦ How far is it (connectivity)
◦ Topology represents the structuring of coordinate data which
clearly describes adjacency, containment, and connectivity.
Topology rules
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Spatial Concepts
Topology - generally, spatial relationships between geometric elements
adjacency
containment
neighborhood
Mathematical property that makes spatial relationships explicit and establishes connectivity betweenthe features on a map
Relationships:
• Adjacency (contiguity)
• Connectivity (network)
• Proximity (distance)
• Containment
Spatial relationship between geographic features—is fundamental to ensuring data quality.
Topology enables advanced spatial analysis
Topology in Geodatabase
Sources of errors
• Age of Data
• Areal Cover
• Map Scale
• Density of Observations
• Relevance
• Format
• Accessibility
• Cost
• Positional Accuracy
• Accuracy of Content
• Faulty Instrument
• Fatigue• Map complexity
– ½ hour to 3 days for a single mapsheet
• Sliver polygons• Wrongly placed labels
Elimination: Selectively eliminating features that are too small, too short
Simplification- Removing unnecessary detail
Aggregation: Combining features in close proximity into a new area feature
Collapse: Reducing a feature dimension or the representation of its spatial extent
Exaggeration-Increasing the spatial extent of a feature - emphasis and legibility
Classification and Symbolization- Grouping features sharing similar geographic attributes into a new,
higher-level feature class and representing it with a new symbol.
Conflict Resolution (Displacement): Detecting feature conflicts and then repositioning the less important
features to satisfy the threshold of separation and other cartographic specifications.
Refinement: Altering & adjusting a geometry to improve its aesthetic (visual) impression
Map Generalization
DSS - Spatial Decision Problems Query - Get information existing in database by pruning.
Analysis – Extract a meaningful conceptual information bycombinations or processing of existing database.
Model – Integrate process phenomenon, predict and make newscenarios
DECISION MAKING
Model
AnalyseQuery
Querying Data
GIS allows querying both on Spatial data and Non-Spatial data
- Using simple SQL statements following DBMS rules
Accordingly Queries are classified into
Spatial Queries – Where, How far, Adjacent to , Containing, Not overlapping etc
Geometry based
Non-Spatial Queries – What is, How many, What type, Having value etc.
Text based - Instead of identifying what exists at a given location, you want to find a
location where certain conditions are satisfied.
Map 4 BedroomsMore than acertain area
Within acertain price Result
More Examples of Non-Spatial Queries with different Conditions
Schools High School Apartments for sale Apartments for salewithin 0.5 km
More Examples of Spatial Queries with different Conditions
* Proximity / Buffer conditions
SPATIAL ANALYSIS• MULTIPLE- LAYER OPERATIONS
• TWO LAYERS
• CHANGE PATTERNS IN LANDUSE
• PRODUCT OF DIFFERENT LAYERS
• INDICES MAP GENERATION
• SPATIAL MODELING
• SOIL EROSION MODELING
• RAINFALL - RUNOFF MODELLING
• AIR POLLUTION SPATIAL MODELLING
• SURFACE ANALYSIS
• VISUALISATION OF 3D OF A SURFACE TO REPRESENT
• VARIETY OF PHENOMENA SUCH AS POPULATION, CRIME,
• MARKET POTENTIAL & TOPOGRAPHY33
Analysis & ModelingVisualization & Description:
Using GIS to create descriptive models of the world--representations of reality as it exists.
Analysis:Using GIS to answer a question or test an hypothesis.
Often involves creating a new conceptual output layer, (or table or chart), the
values of which are some transformation of the values in the descriptive input
layer. --e.g. buffer or slope or aspect layers
Modeling / Simulation / Prediction:Using GIS capabilities to create a predictive model of a real world process, that is, a
model capable of reproducing processes and/or making predictions orprojections as to how the world might appear.
--e.g. flood models, fire spread models, urban growth models
Query and Processing is an essential part of Analysis and Modeling
• Attribute tools - Join/relate, calculations• Topology and Network analysis - geometric networks and solvers• Geo-processing - Batch processing of geometries
Analysis
• Spatial OperationsVector– spatial measurement– statistics– buffer analysis– spatial aggregation– Spatial overlays and
joinsRaster– neighborhood
analysis/spatial filtering– Raster modeling
• Attribute Operations
– record selection» tabular via SQL» ‘information
clicking’ with cursor– variable recoding– record aggregation– general statistical
analysis– table relates and joins
DrainageBasins
UNION :The two layers (land use &drainage basins) do not havecommon boundaries. GIScreates combined layer withall possible combinations,permitting calculation of landuse by drainage basin.
a. b. c.
aGaA bA
bGcAcG
Land Use
A.G.
Atlantic
Gulf
Complex Geospatial queries and integrating multi-disciplinary approach
Severity domains, Impact Assessment & Reports
Zonal Stats: Area, CN and PR
Radiological dose values are generated /updated by dispersion model every hour andingested in the form of grids for –
Thyroid dose Cloud gamma dose Ground Deposition dose
Simulation of Plume movement
Overlay of wind vectors
ONERS – Decision support system for Disaster Management
Geographic Data Model – a conceptual model for describing and reasoning about
the world expressed in a GIS database.
A model is a representation of a physical process or phenomenon by
replicating all its subsystems as functions and parameters, so as to run the
model for understanding, predicting and simulating different scenarios.
A model need not be a part of GIS and may be coupled to it.
Modeling
• Loose coupling
– Use GIS to extract input data and display output
– Model runs independent of GIS
• Tight coupling
– GIS and model are integrated in one system
Drought Monitoring Model
The main characteristics of spatial decision problems include:– Many alternatives - multiple criteria– Consequences of the decision alternatives are spatially variable– More then one decision maker (or interest group) involved in the
decision-making process– Decision makers have different preferences on evaluation criteria and
decision consequences– Decisions are often surrounded by uncertainty
Phases of decision making process
intelligence - is there a problem or an opportunity for change?
design - what are the decision alternatives?
choice - which alternative is best?
SDSS is an interactive, computer-based system designed to support a user or
group of users in achieving a higher effectiveness of decision making while
solving a semi-structured spatial decision problem;
Associated Topics
Ensure that
• Products and services are safe, reliable and of good quality.
• They are strategic tools that reduce costs by minimizing waste and errors and increasing
productivity.
• They help companies to access new markets, level the playing field and facilitate free and fair global
trade.
What is a standard ?A standard is a document that provides requirements, specifications, guidelines or characteristics that
can be used consistently to ensure that materials, products, processes and services are fit for their
purpose.
Geospatial Standards
Open Geospatial Consortium : OGC
An international industry consortium of 496 companies, government agencies and universities participating in a
consensus process to develop publicly available interface standards.
OGC® Standards support interoperable solutions that "geo-enable" the Web, wireless and location-based services
and mainstream IT.
The standards empower technology developers to make complex spatial information and services accessible and
useful with all kinds of applications.
Standards – ISO - OGCStandards – ISO - OGC
Spatial Data Infrastructure
Current and accurate geospatial data should be readily made available to contribute
to local, national, and global economic growth, environmental quality and stability,
and social progress.
SDI
PolicyPolicy
Fundamental Data SetFundamental Data Set
StandardsStandardsAccess NetworkAccess Network
PeoplePeople
Significance
• Support integrated and centralised decision making for substantial and sustainable
development in both the developed and developing countries of the world,
• Reduce duplication-cost and efforts,
• Provide better data for decision making,
• Support new business processes/create opportunities in geospatial industry.
GEOdataFramework
Metadata
Clearinghouse (catalog)
Standards
Towards WebGIS - Internet vs. WWWTowards WebGIS - Internet vs. WWW
Internet is the infrastructure that
makes the WWW work.
• Packet Switching
• TCP/IP Protocol
• Physical Infrastructure
– Fiber-optics lines, wires
– Satellites, Cable Modems
– Routers, Hubs, Network Cards,
WiFi systems, etc.
WWW is just one of many “virtual
networks” built on the Internet.
• Websites: http, https, etc.
• Email: pop, imap, etc.
• Other systems: ftp, instant
messaging, etc.
• Note: Even to this day companies
have “private virtual networks” that use
the Internet, but are proprietary,
locked-down.
What is a Web Service?What is a Web Service?
• Web Service:
“Web-based applications that dynamically interact with other Web
applications using open standards that include XML, UDDI and SOAP”
• Service-Oriented Architecture (SOA):
“Development of applications from distributed collections of smaller
loosely coupled service providers”
“A collection of services or software agents that communicate freely with
each other”
Internet/Web /GIS - WebGISInternet/Web /GIS - WebGIS
Web Server
Databases
Broker
Browsers
Web
Applications
Clients Servers
MashupMashup
• An application that combines data from multiple sources• Referred to as “content aggregation”• Combines similar types of data (e.g., maps,) from different
systems/services• Term originated from music industry when a new song was made from
several existing tracks
+ =
Publishing and DiscoveryPublishing and Discovery
• OGC Catalog Service
– Catalog Service for the Web (CSW)
– ISO 19119 Metadata Profile
– Z39.50 Profile
– OASIS ebRIM Profile
– OpenSearch
• Support publishing and discovery of
distributed geospatial data and associated
services
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METADATA & DISCOVERY
CHATUR SEEMA MAP QUERY AND OUTPUT
DATA ENTRY MODULE
RETREIVED DATA FORTHE VILLAGE
SHOWING DIFFERENTYOJANA DETAILS
YOJANA AND SUB WORKSELECTION DIALOG
GRAMIN YOJANA INFORMATION SYSTEM
DISPLAY MODULE
FOREST MANAGEMENT INFORMATION MODULE
Suggested reading
• Burrough, P.A. 1990. Principles of Geographical Information Systems. Clarendon Press.
Oxford.
• Antenucci, J.C., Brown, K., Croswell, P.L., Kevany, M. and Archer, H. 1991. Geographic
Information Systems: a guide to the technology. Chapman and Hall. New York.
• Star, J. and Estes, J. 1990. Geographic Information Systems: an Introduction. Prentice
Hall. Englewood Cliffs
• Arnoff, 1989. Introduction to GIS
• David J. Maguire (Editor), Michael F. Goodchild (Editor), David Rhind (Editor) :
Geographical Information Systems: Principles and Applications, 2 Vol.
• Keith C. Clarke: Getting Started with GIS (4th Edition)
THANK YOU