Massachusetts Institute of Technology Department of Urban Studies and Planning 11.520: A Workshop on Geographic Information Systems 11.188: Urban Planning and Social Science Laboratory Lecture One: Overview of Course, GIS Principles, Elements of Maps, ArcGIS Basics 1. Overview of Course • Syllabus/Lectures/Labs/Homeworks/Project • Other GIS courses: 11.204, 11.220, 11.521, IAP miniclasses, Harvard, BU. • Student background 2. GIS Principles 2.1 Geographic information • is information about places—spatial dimension • 80% of all information include spatial component - how should one embed location in data • knowledge about both where something is and what it is - with query capability in both directions • geographic resolution o very detailed  information about the locations of all buildings in a city  information about individual trees in a forest o very coarse  climate of a large region  population density of an entire country• characteristics o often relatively static-- e.g., GPS coordinates of fixed features  natural features and many features of human origin don't change rapidly  static information is easier to portray on a static paper map o can be very voluminous  a terabyte (1012 bytes) of data is sent from a single satellite in one day  gigabytes (gigabyte = 109 bytes) of data are needed to describe the US street network Abstraction--Geometrical Representation • Model the boundaries of spatial objects (vector data models) • Point--a single location is enough • MBTA Stops • Is Boston a point?--At different scales or for different purposes, Boston could be a point or polygon. • Line--only one dimension needs to be represented • Street centerline, MBTA Railroad track, ridgeline, bux route • How does it matter if street is modeled as centerline or as void between blocks? • Polygon--2D planar surfaces • Cambridge border,<![endif]> central square boundary,census tract, parcel, ... • What about river boundary, edge of ocean (at high tide?) • Beyond planar surfaces - terrain models, 3D CAD models, ... • Model the space that contains things (raster data models) • 30m x 30m grid cells for Landsat image - classified based on predominate land use within each cell • 6 inch pixels for color orthophotos developed from aerial photography • 3 km x 3km x 1 km (height) volumes for meterological modeling 2.2 Five examples to view and discuss: which are GIS? what to learn? how to add your own data/analyses? • Private sector mapping services o Mapquest or Google-Maps to find a location and generate a street map. www.mapquest.com , maps.google.com o Google-Earth (and Keyhole, Digital Earth, etc.) to navigate and 'fly' over the earth: earth.google.com • Spatial analysis using commercial GIS software o ArcGIS to analyze the demographics and economic development potential of Appalachia - we'll use ArcGIS• Web services using open-source (LAMP) tools o commute sheds and labor sheds for a community (database driven web pages ia servers running Linux/apache/mysql/postgresql/minn-map-server/php): Mapping Metro Boston Growth http://subway.mit.edu/umi/ctpp/ o location-based services: tracking WiFi usage on campus: iSpots, Wireless Technology at MIT (http://ispots.mit.edu/ ) 2.3 Geographic information systems 2.3.1 Definition GIS is a computer-based information system that enables capture, modeling, manipulation, retrieval, analysis and presentation of geographically referenced data. (Worboys, 1997) Other definitions of GIS • A container of maps in digital form. • A computerized tool for solving geographic problems. • A spatial decision support system. • A tool for revealing what is otherwise invisible in geographic information • A tool for automatically performing operations on geographic data. 2.3.2 Components of GIS • Hardware, Software, Data, People, Procedure, Network (Internet) • GIS hardware is like any other computer (nothing special about the hardware) o keyboard, display monitor (screen), cables, Internet connection o with some extra components perhaps • large monitor, disk drive, RAM • maps come on big bits of paper • need specially big printers and plotters to make map output from GIS • need specially big devices (digitizers, scanners,...) to scan and input data from maps to GIS • software o ESRI (http://www.esri.com) o Intergraph Corporation (http://www.intergraph.com ) o Autodesk (http://www.autodesk.com ) o Caliper: GIS Software, Mapping Software (http://www.caliper.com )• what is important is the kind of information that's stored and analyzed o representing and managing information about what is where  the contents of maps and images o special functions that work on geographic information, functions to:  display on the screen  edit, change, transform  measure distances, areas, proximity, adjacency  combine maps of the same area together o useful functions can be much more sophisticated  keep inventories of what is where  manage properties, facilities  judge the suitability of areas for different purposes  help users make decisions about places, to plan  make predictions about the future 2.3.3 Example GIS Applications • Resources inventory (what is available at where?) • Network Analysis (How to get to a place in the shortest amount of time?) • Location Analysis (Where is the best place to locate a shopping mall?) • Terrain Analysis (What is the danger zone for a natural disaster? Visibility analysis) • Spatio-Temporal Analysis (Land use: what has changed over the last twenty years, and why?) Transportation applications • a state department of transportation needs to o store information on the state of pavement everywhere on the state highway network o maintain an inventory of all highway signs o analyze data on accidents, look for 'black spots' • a traveling salesperson needs o a system in the car for finding locations, routes • a delivery company, e.g. Federal Express, UPS, needs to o keep track of shipments, know where they are o plan efficient delivery routes • a school bus operator needs to o plan efficient collection routes • a transit authority needs to o know where transit vehicles are at all times • studies have shown substantial savings when routes and schedules are