What is GIS GIS = Geographic Information Systems; What Information are we talking about? Information about anything that has a place (e.g. locations of features, address of people) on Earth s surface, i.e. has coordinates Information about those features or people, i.e. descriptions about them in tabular form
What is GIS GIS: a computer-based system/ Information System of: Capturing (data input is most time consuming) Storing (in various formats) Manipulating (editing, subtracting, etc.) Displaying (map, graphs, tables, etc.) Querying (finding subsets of data) Analyzing (seeing relationships between variables or parameters) of geographically referenced data in order to support decision making for planning and management of land use, natural resources, environment, transportation, urban facilities, and other records
Components of GIS Key components of GIS are: Computer system Geospatial data Users Geospatial Data Computer System Users Figure: Key components of GIS
Computer System for GIS Hardware System Central Processing Unit (CPU) Memory (RAM) > 64 MB I/O Device Plotters, printers, mouse, digitizers, scanners, digital camera Software System Operating System DOS, Windows Compiler C++, Pascal, Fortran, BASIC Application Programs ArcGIS, MGE, Geo/SQL, GFIS, IDRISI*, GRASS* *public domain software
Components of GIS : Users / Systems
G Components of GIS : Data Sources Digitized and Scanned Maps purchased, donated, free (Internet) created by user Data Bases Tables of data GPS Global Positioning System accurate locations Field Sampling of Attributes Remote Sensing & Aerial Photography
Components of GIS : Geospatial Data Location Data How Many? What Kind? Where? Scale of Data Global to Local Data Presentation Words, Charts, Graphs, Tables, Maps, Photos
Classification of Geospatial Data Graphical data (called geometric data) Attributes (called thematic data) Real World Data Model Spatial Objects Points Lines Areas Vector Raster Form Pixels in Raster Attributes in Tables Figure: Concept of Geospatial Data
Classification of Geospatial Data
Two Types of Data Used in GIS Vector Data Discrete features Points: wells, outcrops, hydrants, tel. poles Lines: roads, rivers Areas: landuse, veg. types, soil types Uses points with x, y coor. Can be topological or non-topological data Raster Data Continuous features Uses grids and cells with unique values Rainfall, surface elevation, depths, soil erosion Simple data structure (rows & columns) File size depends on cell (pixel) resolution We ll revisit this topic in more details
Vector vs. Raster Data Figure 1.2 The vector data model uses x-, y-coordinates to represent point features (a), and the raster data model uses cells in a grid to represent point features (b).
GIS answers the following Location: What is at?... Condition: Where is it? Trends: What has changed since?... Patterns: What spatial patterns exist? Modeling: What if? Exploring data using GIS turns data into information into knowledge
How is GIS Different from Other Digital Maps? GIS = dynamic relations between spatial data (georeferenced) & relational data (attribute of features in tabular forms) GIS can show descriptions of a feature in form of maps (e.g. query) You can get description of a feature shown on a map (e.g. identify)
Power of GIS: Visualization A picture is worth a thousand words
Maps and Databases are Interactive
Comparison of GIS with other Information Management
GIS Versus Manual Works Maps GIS Manual works Storage Standardized and integrated Different scales on different standard Retrieval Digital Database Paper Maps, Census, Tables Updating Search by Computer Manual Check Overlay Very Fast Expensive & Time consuming Spatial Analysis Easy Complicated Display Cheap & Fast Expensive
What Can GIS Do? GIS deals with digital (virtual) maps Overlays maps with various themes or layers Unlike paper maps, all of these themes are transparent, i.e. you can see a theme that is covered by another theme
Overlapping of layers or themes of an area Figure 1.9 A vector-based overlay operation combines spatial data and attribute data from different layers to create the output.
Overlapping of raster layers of an area Figure 1.10 A raster data operation with multiple rasters can take advantage of the fixed cell locations.
GIS Can Also Change map scales easily Add, remove, hide themes Copy maps as many times as you want Edit colors, symbols, labels
What Else Can GIS Do? )cont d( Imports & exchanges data from other sources & formats (we will do in the lab) Projects & re-projects maps We will have a separate lecture & Lab on this topic Geocodes text files/street addresses
Which Disciplines Can Use GIS? Virtually anyone who needs information that can be tied to a location on Earth (i.e. people through their addresses or features through their geographic locations
GIS as Multidisciplinary Science Statistics Operations Research Computer Science Mathematics Civil Engineering Urban Planning Geography Cartography Remote Sensing Photogrammetry Surveying Geodesy
Area of GIS Applications Area Facilities Management Environmental and Natural Resources Management Street Network Planning and Engineering Land Information GIS Applications Locating underground pipes & cables, planning facility maintenance, telecommunication network services Environmental impact analysis, disaster management and mitigation Locating houses and streets, car navigation, transportation planning Urban planning, regional planning, development of public facilities Taxation, zoning of land use, land acquisition
GIS Applications Business Site Location, Delivery stems, Marketing Government Local, State, Federal, Military Economic Development Population Studies, Incomes, Census and Demographic Studies Emergency Services Fire & Police Environmental Monitoring & Modeling Industry Transportation, Communication, Healthcare Mining, Pipelines, Public Health Epidemiology Studies Urban Planning Land Use, Historic studies, Environmental and Conservation Studies, Housing Studies, Crime Analysis Politics Elections and Reappointment Education Research, Teaching Tool, Administration Wherever Spatial Data Analysis is Needed
GIS Information Infrastructure Police and Fire Cable and Pipe Transportations Urban Infrastructure Social Infrastructure GIS Information Infrastructure Population Land Use Cadastre etc. Environmental Infrastructure Economic Infrastructure Marketing Banking Car Navigations etc. Educational Infrastructure Natural Resources Pollution Disaster etc. Basic knowledge Computer assisted education
Environmental Analysis
Crime Analysis Crimes by Neighborhood2003 City of Pittsburgh Robberies Homicides Robbery 0-6 7-14 15-23 24-38 39-82 No Data Homicide 0 1 2 4-3 6-5 No Data
Business IKEA's Store Locations Compared to Household Income (! ^_!(!( (! _(! ^ (!! (!(! ( (! (!(! ( (!(!!!(! (((!! (! (! _^ _ ^ (!
More Applications of GIS Hydrogeologists monitor water quality and relate to landuse Biologists can track trends in invader species spread over years Ecologists can assess suitable habitat for a species Businessmen can study feasibility of a new location Engineers can find least-cost path for a new road Imagination is your limit! Now, you come up with some examples
GIS Operations Spatial Data Input Attribute Data management Data Display Data Exploration Data Analysis GIS Modeling
Classification of GIS Operations Getting progressively more involved 1.8Figure A classification of GIS.operations
Why GIS is needed? Common problems of handing geospatial information: Geospatial data are poorly maintained. Maps and statistics are out of date. Data and information are inaccurate. There is no data retrieval service. There is no data sharing.
Benefits once GIS is implemented Geospatial data are better maintained in a standard format. Revision and updating are easier. Geospatial data and information are easier to search, analysis and represent. More value added product. Geospatial data can be shared and exchanged freely. Productivity of the staff improved and more efficient. Time and money are saved. Better decision can be made.
GIS Is Not a Software GIS is a Concept a Science not a software