Overview of GIS

1. Overview of GIS Andrew Rowan, Ph.D. Director The GIS Center at Stony Brook

2. Overview of GIS: Outline • Introduction: What is GIS? • Software Options • Finding the Data

3. Introduction

4. What is GIS? • GIS = Geographic Information System • What is it? The cocktail party answer: maps on a computer. But really much more. • G + IS: Geographic/Spatial info, backed up with a database of attributes • Ties together disparate info sources, provides new ways to use them

5. WHERE it is Each object drawn as a point, line, or polygon Locations stored in X,Y coordinates referenced to a common coordinate system WHAT it is Every feature has a corresponding record in a database describing it “Layers” of information stored separately but used together Not Just a Drawing, a Database

6. Where it is/What it is

7. Where What is? • What is the “it”? ANY information that is associated with a location can be used in GIS • Physical objects: houses, streets, fire hydrants, rivers, landfills, etc. • Characteristics of the land: soil type, geology, elevation, etc. • Human factors: governmental boundaries, property ownership, demographic info, crime events, pizza orders, etc. • Usually you start out knowing one (what or where) and ask the system to show you the other

8. Four Major GIS Functions • Data Capture – keying in, digitizing, scanning, converting • Data Storage and Manipulation – File management, editing, documentation • Data Analysis • Data Display – maps, reports, interactive displays

9. Database Queries • Query “from the map”: starting with a location, GIS gives you information about what is there

10. Database Queries • Query “to the map”: you specify WHAT you are looking for, GIS tells you WHERE it occurs

11. Not Just Maps, Answers – GIS Can Do Spatial Queries • How many gas stations (points) are located in areas with permeable soil above aquifer X? • How many miles of roads (line) pass through areas of salt-sensitive vegetation (polygon)? • How much of the area within 100 feet of the river is forested? • Show the parcels that are over 100 acres, near the highway, not near wetlands or water, and zoned industrial • Retrieve population data for the census blocks within the watershed.

12. Advanced Spatial Queries • How many houses can be built here under each of the zoning options we are considering? • What fire company is closest to this house that just called 911, and what’s the fastest (not shortest) route to get there? Print the driving directions. • Draw a corridor from A to B that crosses the least amount possible of wetlands, steep slopes, powerful landowners. Avoid certain areas altogether.

13. Spatial Query Examples (cont.) • Address-matching (“geocoding”): A list of addresses is converted to points on a map by referencing them to a special street network.

14. GIS Software

15. Some Software Options Free • ArcExplorer (ESRI) • Browsing GIS-enabled web servers Midrange – “Desktop Mapping” • ArcView (ESRI) • MapInfo (MapInfo) • GeoMedia (Intergraph) • IDRISI (Clark University; raster GIS) High-End – “Professional GIS” • ArcInfo (ESRI) • GeoMedia Pro (Intergraph)

16. ESRI Software • ArcExplorer • Zero-cost software • Limited functionality; mainly designed for on-screen browsing and querying; no printed map layouts or data creation • ArcView 3.x • Fairly strong desktop mapping software • Modest hardware requirements (can run on Pentium, 32 MB) • ArcView 8.x • More tightly integrated with current product line • Somewhat more powerful than 3.2 • Very much higher hardware demands (Pentium III, 256 MB RAM) and requires Win NT/2000 or XP

17. ESRI Software (cont.) • ArcEditor and ArcInfo • More advanced functions for creating and manipulating spatial data, object-oriented database design, etc. • Extensions • ArcView (both versions) and ArcEditor/ArcInfo have optional extensions that add specialized capabilities such as raster (grid-based) analysis, three-dimensional visualization, spatial statistics • ArcIMS • Internet Map Server, for setting up GIS applications on a web server

18. Software and Equipment Donations • ESRI has donated copies of ArcView 3.x and ArcView 8.x to New Jersey nonprofit organizations, libraries, and environmental commissions. The program is administered by the NJ Office of GIS. For more info, check the NJ Spatial Data Clearinghouse, http://njgeodata.state.nj.us • Conservation Technology Support Program www.ctsp.org • ESRI Conservation Program www.conservationgis.org

19. Finding the Data

20. Data Clearinghouses • FGDC, the Federal Geographic Data Committee,sets standards for data accuracy as well as metadata content and format. Also coordinates the National Spatial Data Infrastructure (NSDI), a distributed network of information servers and search engines for GIS data: www.fgdc.gov/nsdi • NJ Spatial Data Clearinghouse njgeodata.state.nj.us • Geography Network www.geographynetwork.com

21. Data Sources: Federal • US Geological Survey (basemaps, elevation, etc.) – mapping.usgs.gov • USDA/Natural Resource Conservation Service (soils) – www.nrcs.usda.gov/technical/dataresources/ • US Census Bureau (census results, TIGER roads, census enumeration areas (blocks, tracts, etc.) – www.census.gov • FEMA – www.fema.gov/msc/product.htm • US Fish and Wildlife Service – www.fws.gov/data By law, all data from federal agencies is in the public domain

22. Data Sources: State (NJ) • NJDEP www.state.nj.us/dep/gis • NJGS www.state.nj.us/dep/njgs • NJDEP Fish, Game and Wildlife www.state.nj.us/dep/fgw • NJDEP Endangered and Non-Game Species program www.state.nj.us/dep/fgw/ensphome.htm • NJDOT www.state.nj.us/transportation/gis • NJ Office of State Planning www.state.nj.us/osp

23. Data Sources: Local • Some local governmentsproduce digital data (parcel maps, high-res photography) • Some NGO’s do as well • Spatial data clearinghouse is a good first place to check – njgeodata.state.nj.us