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Introduction to Geographic Information Science University of Washington – Bothell September 14, 2005

Introduction to Geographic Information Science University of Washington – Bothell September 14, 2005. Phil Hurvitz College of Forest Resources College of Architecture & Urban Planning University of Washington - Seattle. Overview. Today will be a cursory overview of GIS technology.

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Introduction to Geographic Information Science University of Washington – Bothell September 14, 2005

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  1. Introduction to Geographic Information ScienceUniversity of Washington – BothellSeptember 14, 2005 Phil HurvitzCollege of Forest ResourcesCollege of Architecture & Urban PlanningUniversity of Washington - Seattle

  2. Overview • Today will be a cursory overview of GIS technology. • By the end of the day, students will: • be able to define GIS • understand the basic building blocks of the technology • understand how GIS is applied in many different settings • have obtained some hands-on experience using current software and real-world data sets • know where to look for GIS data • understand a basic set of GIS analytical functions

  3. Schedule

  4. Schedule

  5. Introduction to GIS • Overview • Why use a GIS? • What can a GIS do? • How does a GIS work? • GIS definitions_

  6. Introduction to GIS • Overview • Why use a GIS? • What can a GIS do? • How does a GIS work? • GIS definitions_

  7. Why use a GIS? • An extension of the paper map, but much more than a map, as you will see • GIS uses the analytical power of the computer to complete complex tasks • Computer's storage power to manage large data sets. • Integration of many different types of data from many different sources • GIS maps a variety of different data to the same coordinate space (allows for combination of data)_

  8. Why use a GIS? • Digital media are more stable than paper media, and easier to distribute via the Internet • Faster and easier update • Creation and use of "one-time" maps • Tailor-made maps • Elimination of some user bias (identical systematic routines, machine calculations) • GIS brings new tools for thinking differently about the properties of objects in space._

  9. Introduction Overview • Why use a GIS? • What can a GIS do? • How does a GIS work? • GIS definitions_

  10. What can a GIS do? • Generically • Find features with known properties but unknown location (“Where is a particular feature on the landscape?”)(“Where are features with specific properties?”) • Identify properties of features with known location(“What type of features are at a specific location?”) • Analyze the relationship between/among features and location(“Is there a reason these features are found at this location?”)_

  11. What can a GIS do? • Specifically • Estimate economic effects of land-use regulation(Spotted owl, salmon) • Determine the optimal locations of new businesses(demographics, transportation) • Generate optimal routing and scheduling delivery and repair services(network & routing) • Determine the ground area covered by a new cellular phone network(visibility and line-of-sight analysis)_

  12. What can a GIS do? • Specifically • Delineate watershed boundaries for estimates of sedimentation effects on fish-bearing streams • Predict vegetation types based on elevation, slope, and aspect • Predict landslide hazard for forest harvest units • Calculate the correlation between demographics and HIV infection rates • Locate natural areas that need protection • Make communicative, colorful, and interesting maps_

  13. query criteria are defined location is shown Examples of what a GIS can do Example 1: Where is a given feature or set of features? “Where are forest stands greater than 100 years of age?”

  14. 1st step: select road Examples of what a GIS can do • Example 2: What features are at a given location? “What is the age of the forest near the 1050 Road?”

  15. 2nd step: select adjacent stands Examples of what a GIS can do • Example 2: What features are at a given location? “What is the age of the forest near the 1050 Road?”

  16. 3rd step: examine records of adjacent stands Examples of what a GIS can do • Example 2: What features are at a given location? “What is the age of the forest near the 1050 Road?”

  17. Examples of what a GIS can do • Example 3: Where are areas that meet a given complex set of criteria? “What parts of the forest are located: • within 100 ft of a stream, • beyond 50 ft from a road, • on greater than 30% slope?”

  18. Examples of what a GIS can do • closer than 100 ft to a stream, and • farther than 50 ft from a road, • on > 30% slope?

  19. Examples of what a GIS can do • closer than 100 ft to a stream, and • farther than 50 ft from a road, • on > 30% slope?

  20. essentially a calculus problem approximated quantitatively Examples of what a GIS can do • Example 4: How can GIS calculate distance of features? “How far away is a bird nest from the rest of the patch of nesting habitat?”

  21. Examples of what a GIS can do • Example 5: How can data to support watershed analysis be generated within a GIS? “What are the road and stream densities (mi / sq. mi) for the forest area?”

  22. Examples of GIS generated maps detailedtopographic maps

  23. Examples of GIS maps orthophoto image maps good for validating other data

  24. Examples of GIS maps surface drapes & 3-D modeling

  25. Examples of GIS maps classified (thematic) maps good for understanding data with many unique values

  26. Examples of GIS maps documentation of research

  27. Introduction Overview • Why use a GIS? • What can a GIS do? • How does a GIS work? • GIS definitions_

  28. coordinate data each feature hasa record tabular data How does GIS work? Combination of and

  29. Introduction Overview • Why use a GIS? • What can a GIS do? • How does a GIS work? • GIS definitions_

  30. GIS definitions "A system of hardware, software, and procedures designed to support the capture, management, manipulation, analysis, modeling and display of spatially-referenced data for solving complex planning and management problems."

  31. hardware, • software, • data, • people, and • methods GIS definitions A working GIS integrates five key components:

  32. GIS definitions What is the difference between GISystems and GIScience? GISystems refer to the classic GIS definition • technology to support geospatial analysis in a computing framework • think “tools,” “technology,” and “technicians,” GIScience refers to the use of GIS to support scientific understanding and approaches • think “approaches,” “theory, “science,” and “scientists” The distinction is not clear-cut

  33. GIS Skill Set • Skills necessary to succeed in GIS: • Computing proficiency • Use of file system • Knowledge of various applicatons • Programming is a big plus • Basic mathematics • Algebra, geometry, trigonometry • Ability to work independently (i.e., reading documentation) • Spatial cognition & imagination (think organic chemistry)

  34. Introduction to GIS • Questions?

  35. Schedule

  36. GIS Fundamentals • Overview • Spatial (coordinate) data model • Relational (tabular) data model • Scale issues • Projections & coordinate systems • Course exercise/sample data_

  37. GIS Fundamentals • Overview • Spatial (coordinate) data model • Relational (tabular) data model • Scale issues • Projections & coordinate systems • Course exercise/sample data_

  38. Spatial Data Model: Basic Data Types • GISystems are driven by spatial data • 2 basic spatial (coordinate/geometric) data models exist • vector: based on geometry of • points • lines • polygons • raster: based on geometry of • grid cells (images, bitmaps, DEMs)_

  39. airports are point features each point is stored as a coordinate pair Vector Data Model Points: represent discrete point features each point locationhas a record in thetable

  40. roads are linear features Vector Data Model Lines: represent linear features each road segmenthas a record in thetable

  41. node node vertex vertex vertex vertex Vector Data Model Lines: fundamental spatial data model • Lines start and end at nodes • line #1 goes from node #2 to node #1 • Vertices determine shape of line • Nodes and vertices are stored as coordinate pairs_

  42. landforms and water are polygonal features Vector Data Model Polygons: represent bounded areas each bounded polygonhas a record in thetable

  43. Vector Data Model Polygons: fundamental spatial data model • Polygon #2 is bounded by lines 1 & 2 • Line 2 has polygon 1 on left and polygon 2 on right_

  44. Vector Data Model Polygons: fundamental spatial data model • complex data model, especially for larger data sets • “arc-node topology,” used for ArcInfo data sets or defined by rules in the Geodatabase_

  45. Vector Data Model • Major types (formats) of vector data available in ArcGIS • ESRI GeoDatabases • ESRI shapefiles • ArcInfo coverages and libraries • CAD files (AutoCAD DWG, DXF;Microstation DGN) • StreetMap files • Spatial Database Engine (SDE) data • ASCII point coordinate data • Linear measure (route) data_

  46. Vector Data Model • ESRI Geodatabases • 1º preferred vector format in ArcGIS • Display very quickly • Fully editable (coordinate and tabular) in ArcGIS • Stored in RDBMS (MS Access on PC = “personal geodatabase”; industrial-strength DB for ArcSDE = “SDE geodatabase”) • Convenient storage format • Geodatabase can store many files from many source formats • Data sets are either point or line or polygon_

  47. Vector Data Model • ESRI shapefiles • 2º preferred vector format in ArcGIS • Display quickly • Fully editable (coordinate and tabular) in ArcGIS • Simple in structure • Do not use arc-node topology • “Connected” lines do not necessarily share a common node • Adjacent polygons do not share common bounding arcs • Data sets are either point or line or polygon_

  48. Vector Data Model Shapefile & geodatabase polygon spatial data model • less complex data model • polygons do not share bounding lines

  49. Vector Data Model • ArcInfo coverages • Commonly found format (due to ArcInfo market dominance) • Data model more complex • Display more slowly in ArcGIS • Coordinate data not editable in ArcGIS • Polymorphic (point/line/polygon/route/annotation/…) • Problematic OS file structure (more on this later in the term)_

  50. Vector Data Model ArcInfo coverage spatial data model • polygons share bounding lines • same topological rules can be built into Geodatabase

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