(Geographic Information Systems) Fundamentals Muhammad Iqbal Hajana Senior Assistant Professor E&ES Department, Bahria University • Email: hajana@hotmail.com Contents • • • • • What is GIS? Principle of GIS Function of GIS Components of GIS Type of GIS Advantages of GIS • Application of GIS What is GIS? • GIS is a computer system capable of assembling, storing, manipulating and displaying geographically referenced information, i.e data identified according to their locations. • A GIS is an organized collection of computer hardware, software, geographic data and personnel to efficiently capture, store, update, manipulate, analyze and display all forms of geographically referenced information. Principle • Data Capture – Data source are mainly obtained from manual digitization and scanning of aerial photographs, paper maps and existing digital data sets. • Database Management and Update – Data security, data integrity and data storage and retrieval, and data maintenance abilities. • Geographic Analysis – The collected information is analyzed and interpreted qualitatively and quantitatively. • Preparing Results – One of the most exciting aspects of GIS technology is the variety of different ways in which the information can be presented. Functions • Data Capture – The input of data into a GIS can be achieved through different methods of gathering. e.g aerial photography, scanning, digitization, GPS. Ways to gather data. • Data Storage – Some data is stored as a maps while others such as digital data stored on digital drives. • Data Manipulation – Digital data can be edited, this allows for many attributes to be added, edited or deleted to the specification of project. • Query and Analysis – GIS is used widely in decision making process for the way commission districts. Use population data to help establish an equal representation of papulation to area for each districts. • Visualization – This represents the ability to display our data in the form of maps, graphs, and tables. Components • Hardware – Computer system, scanner, printer, plotter, flat board, screens • Software – GIS software in use are MapInfo, ARC/Info, AutoCAD etc • Data – GIS will integrate spatial data with other data resources and can even use DBMS, used by most organization to maintain their data, to manage spatial data. – Geographic data and related tabular data can be collected in house or purchased from a commercial data provider. • People – GIS users range from technical specialists who design and maintain. • Method – The map creation can either be automated raster to vector creator or it can be manually victories using the scanned images. Data Types • Vector – Points – Lines – Polygons • Raster – Cell – Pixels – Elements Advantages and Disadvantages (Vector) • Advantages – Good representation of data – Use small file size – Accurate map output • Disadvantages – Complex Data – Expensive technology – Analysis is complex Advantages and Disadvantages (Raster) • Advantages – – – – Simple data structure Cheap technology Analysis is simple Same grid cell for several attributes • Disadvantages – – – – – Large Data volume Inefficient use of computer storage Difficult network analysis Less accurate or attractive maps Less information when using large cells Advantages of GIS • GIS allows us to view, understand and visualize data in many ways that reveal relationships, patterns, and trends in the form of maps, globes, reports and charts • A GIS helps your answer questions and solve problems by looking at your data in a ways that is quickly understood and easily shared. • GIS give accurate information • Better prediction and analysis to make descion. Disadvantages of GIS • Excessive damage in case of internal fault. • Long outage periods as repair of damaged part • Expensive software • Integration with traditional map is difficult. GIS--What is it? No easy answer anymore! • Geographic/Geospatial Information – information about places on the earth’s surface – knowledge about “what is where when” (Don’t forget time!) – Geographic/geospatial: synonymous • GIS--what’s in the S? – Systems: the technology – Science: the concepts and theory – Studies: the societal context GIS--What is it? No easy answer anymore! • GIS is a system that creates, manages, analyzes, and maps all types of data. • GIS connects data to a map, integrating location data (where things are) with all types of descriptive information (what things are like there). • This provides a foundation for mapping and analysis that is used in science and almost every industry. • GIS helps users understand patterns, relationships, and geographic context. • The benefits include improved communication and efficiency as well as better management and decision making. (https://www.esri.com/en-us/what-is-gis/overview) Geographic 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 (GIS) – 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 GIS. A GIS provides for storing analyzing and manipulating GPS and RS data. GI Systems, Science and Studies • Systems Which will we do? – 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 Defining Geographic Information Systems (GIS) • The common ground between information processing and the many fields using spatial analysis techniques. (Tomlinson, 1972) • A powerful set of tools for collecting, storing, retrieving, transforming, and displaying spatial data from the real world. (Burroughs, 1986) • A computerised database management system for the capture, storage, retrieval, analysis and display of spatial (locationally defined) data. (NCGIA, 1987) • A decision support system involving the integration of spatially referenced data in a problem solving environment. (Cowen, 1988) An Inelegant Definition for GISy A system of integrated computer-based tools for end-toend 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. • set of integrated tools for spatial analysis • encompasses end-to-end processing of data – capture, storage, retrieval, analysis/modification, display • uses explicit location on earth’s surface to relate data • aimed at decision support, as well as on-going operations and scientific inquiry Geographic Information System: intuitive description • A map with a database behind it. • A virtual representation of the real world and its infrastructure. • A consistent “as-built” of the real world, natural and manmade Which is • queried to support on-going operations • summarized to support strategic decision making and policy formulation • analyzed to support scientific inquiry How GIS differs from Related Systems • DBMS--typical MIS data base contains implicit but not explicit locational information • • – city, county, zip code, etc. but no geographical coordinates – is 100 N. High around the corner or across town from 200 E Main? automated mapping (AM) --primarily two-dimensional display devices – thematic mapping (choropleth,etc such as SAS/GRAPH, DIDS, business mapping software) unable to relate different geographical layers (e.g zip codes and counties) – automated cartography--graphical design oriented; limited database ability facility management (FM) systems-– lack spatial analysis tools • CAD/CAM (computer aided design/drafting)--primarily 3-D graphic creation (engineering design) & display systems – don’t reference via geographic location • CAD sees the world as a 3-D cube, GIS as a 3-D sphere • – limited (if any) database ability (especially for non-spatial data) scientific visualization systems--sophisticated multi-dimensional graphics, but: – lack database support – lack two-dimensional spatial analysis tools Why Study GIS? • 80% of local government activities estimated to be geographically based – plats, zoning, public works (streets, water supply, sewers), garbage collection, land ownership and valuation, public safety (fire and police) • a significant portion of state 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 natural resource exploration (petroleum, etc.) precision agriculture – civil engineering and construction • Military and defense – Battlefield management – Satellite imagery interpretation • scientific research employs GIS – geography, geology, botany – anthropology, sociology, economics, political science – Epidemiology, criminology The major areas of GIS application • 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 Examples of Applied GIS • Urban Planning, Management & Policy – – – – – – – – • – – – Monitoring environmental risk Modeling stormwater runoff Management of watersheds, floodplains, wetlands, forests, aquifers Environmental Impact Analysis Hazardous or toxic facility siting Groundwater modeling and contamination tracking Political Science – – – Redistricting Analysis of election results Predictive modeling Civil Engineering/Utility – – – • • Attendance Area Maintenance Enrollment Projections School Bus Routing Real Estate – – – • Demographic Analysis Market Penetration/ Share Analysis Site Selection Education Administration – – – • Locating underground facilities Designing alignment for freeways, transit Coordination of infrastructure maintenance Business – – – Environmental Sciences – – – • Zoning, subdivision planning Land acquisition Economic development Code enforcement Housing renovation programs Emergency response Crime analysis Tax assessment • Neighborhood land prices Traffic Impact Analysis Determination of Highest and Best Use Health Care – – – Epidemiology Needs Analysis Service Inventory What GIS Applications Do: manage, analyze, communicate • make possible the automation of activities involving geographic data – – – – map production calculation of areas, distances, route lengths measurement of slope, aspect, viewshed logistics: route planning, vehicle tracking, traffic management • allow for the integration of data hitherto confined to independent domains (e.g property maps and air photos). • by tieing data to maps, permits the succinct communication of complex spatial patterns (e.g environmental sensitivity). • provides answers to spatial queries (how many elderly in Richardson live further than 10 minutes at rush hour from ambulance service?) • perform complex spatial modelling (what if scenarios for transportation planning, disaster planning, resource management, utility design) GIS System Architecture and Components Data Input Query Input Output: Display and Reporting Geographic Database Transformation and Analysis Knowledge Base for GIS Computer Science/MIS graphics visualization database system administration security Geography and related: cartography geodesy photogrammetry landforms spatial statistics. Application Area: GIS public admin. planning geology mineral exploration forestry site selection marketing civil engineering criminal justice surveying The convergence of technological fields and traditional disciplines.
