1. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. GIS BOOT CAMP Todd Bacastow

2. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Geography matters! ‘Geographic Information’ is information which can be related to specific locations. Most human activity depends on geographic information.

3. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Topic 1: What is GIS? Dozens of possible definitions Some emphasise the technology  The Hardware  The Software Others focus on applications  Other terms often encountered: LIS, AM/FM, Geo-information systems, etc.  May emphasise different roles for the system, e.g. spatial decision support system, spatial database system, etc.

4. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. One definition of GIS (Dueker and Kjerne, 1989) “Geographic Information Systems - A system of hardware, software, data, people, organizations and institutional arrangements for collecting, storing, analysing, and disseminating information about areas of the Earth”

5. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. GIS as a tool Majority view of GIS Focus is on hardware, software and routines A technocentric perspective The favoured viewpoint of the system vendors

6. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. GIS as science Emphasis is on data, human uses, contexts A more academic perspective Geographic information science is the “science behind the systems” Includes concepts of spatial reasoning, cognition, human- machine communication, visualisation, data modelling, etc.

7. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. GIS is a product of a particular culture Most GIS developed in Europe/N. America USA: Arc/Info, ArcView, Intergraph, Bentley, Autodesk, MAP, GRASS... Canada: Caris, Spans, GeoVision... France: GeoConcept, Carto 2-D... UK: Smallworld, GIMMS, Laserscan... Netherlands: ILWIS, PC Raster...

8. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. GIS is a commercial product Developments often driven by commercial considerations, less by scientific ones Vendor’s decisions usually based on questions of profitability Critical evaluation of proprietary GIS is rare

9. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. What GIS is not GIS is not simply the technology: it also has a (growing and important) conceptual base GIS can not produce good results from bad data or poor conceptual frameworks GIS is not simply a program to produce maps GIS is not a substitute for thinking! GIS is not the universal answer to all problems!

10. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Topic 2: Sources of Spatial Data

11. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Data input - a major bottleneck Costs of input often >80% of project costs Labor intensive, tedious, error- prone Construction of the database may become an end in itself the project may not move on to analysis of the data collected Essential to find ways to reduce costs, maximise accuracy

12. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Sources of digital map data National Mapping Organization Other government agencies Commercial data vendors

13. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Standards standards may be set to assure uniformity within a single data set or across several data sets ensure the data can be shared across different hardware and software platforms

14. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. What if the Data do not exist at all? Field data capture May be done manually (e.g. direct survey), automatically (e.g. automatic data loggers, etc.) or a combination of the two Remote sensing Includes satellite imagery, geophysical survey, air photos May be used as alternative source of data

15. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Integrating different data sources: issues Formats many different format standards exist a good GIS can accept and generate datasets in a wide range of standard formats

16. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Integrating different data sources: issues Projections Many ways exist to represent curved surface of the earth on a flat map Some projections are very common A good GIS can convert data from one projection to another, or to latitude/longitude Input derived from maps by scanning or digitizing retains the original map's projection With data from different sources, a GIS database often contains information in more than one projection, and must use conversion routines if data are to be integrated or compared

17. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Integrating different data sources: issues Scale data may be input at a variety of scales scale is an important indicator of accuracy maps of the same area at different scales will often show the same features variation in scales can be a major problem in integrating data

18. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Integrating different data sources: issues Resampling rasters Raster data from different sources may use different pixel sizes, orientations, positions, projections Resampling is the process of interpolating information from one set of pixels to another Resampling to larger pixels is comparatively safe, resampling to smaller pixels is very dangerous

19. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Topic 3: Representing Spatial Entities

20. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Representing Spatial Entities The object-focused approach Based on recognition of discrete objects or entities May be layer-based or object-oriented Usually represented by Vector GIS

21. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Two ways of representing space in a GIS The Tesseral (field-oriented) approach Typically seen in Raster GIS Also in some other models

22. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Vector data models Based on the recognition of discrete objects or entities The location/boundaries of these objects defined with respect to some coordinate system Emphasis is on boundaries, space within and between boundaries implied Objects are usually defined in terms of points, lines and areas Complex graphic objects are seen as amalgamations of simpler ones Typical Vector GIS include ARC/INFO, MapInfo Intergraph MGE

23. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. The vector data model Sequences of points can be used to define lines Lines themselves can be aggregated to represent Networks Boundaries of polygons and regions Topographic features (contours, breaks of slope, etc.).

24. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Topology An essential element of vector GIS A distinct branch of mathematics Defines spatial relationships between objects Adjacency, connectivity, containment, etc. Essential for most vector GIS operations

25. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Advantages and disadvantages of the vector approach Lower data volumes More adaptable to variations in scale/resolution of phenomena Tends to be more suited to social and economic applications Disadvantages: Less adaptable to uncertainty, fuzziness Often no “lowest common denominator” of aerial unit.

26. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Objects versus layers Major point of discussion in GIS since mid-1980s Alternative strategies for vector representation of geographic space a “stacked” sequence of layers a collection of discrete objects Difference in how contents of the database represents the real world Echoes wider developments in Computer Science

27. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. The Object view More closely mirrors natural ways of seeing the world Objects usually used in speaking, writing, thinking about the world Objects are fundamental to our understanding of geography Object-oriented approaches may offer data storage and processing advantages

28. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. What are these objects? Graphics objects can be points, lines, areas Geographic objects can be roads, houses, hills, etc. A space can be occupied by many, or no, objects A river is an object (has an identity, name, coordinates, properties, etc.) A line is an object (also has an identity, name, coordinates, properties, etc.)

29. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Applications of object view: Utilities and facilities management Concept of empty space littered with objects fits many needs of managing infrastructure Two or more objects may occupy same horizontal position, separated vertically Smaller objects may be part of larger ones (e.g. pipes as part of networks) and vice versa Idea of a variable measured everywhere on Earth has little relevance

30. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. The Layer view Locations specified by a system of coordinates Geography of real world conceptualised as a series of variables (soils, land use, elevation, etc.) Each layer in the database represents a particular variable

31. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. The Layer view Layer view often more compatible with theories of atmospheric, ocean processes Object view is less compatible with concept of continuous change Good for resource management applications Much data for environmental modelling derived from remote sensing Implies a layer view

32. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Disadvantages The layer approach usually requires many different files to represent each layer Some files contain the actual data Some contain registration information Some contain topological information to construct complex geometries from more primitive ones

33. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Applications of layer view Resource management geographic variation can be described by relatively small amount of variables conceptualisation reasonably constant between scales movement of individuals can lead to difficulties of representation and tracking across layers

34. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Tesseral approaches to GIS

35. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Tesseral geometries From the Greek, tetara or Latin tessella = a tile Tessallations are “sets of connected discrete two-dimensional units” thus mosaics or tilings of space May be regular or irregular Focus is on space occupancy Emphasis is on areas, boundaries are implied

36. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Types of tessallation Regular tessalations Rasters Irregular tessalations Quadtrees Voronoi Tessalations Triangulated Irregular Networks (TINs)

37. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. The raster “Raster Data are spatial data expressed as a matrix of cells or pixels, with spatial positioning implicit in the ordering of the pixels” (AGI 1994) Raster data structure widely used in GIS e.g. IDRISI, GRASS, Arc/Info’s GRID module

38. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Why use rasters? Raster data from other disciplines Ideal for representing continuous variations in space Common way of structuring digital elevation data Assumes no prior knowledge of the phenomenon Uniform, regular sampling of reality

39. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Why use rasters? Often used as common data exchange format Raster algorithms often simpler and faster Easy to program, less need for special hardware Raster systems tend to be cheaper than vector

40. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Issues and trade-offs May give very large data files  typical raster databases may contain > 100 layers  each layer typically contains hundreds or thousands of cells Many options exist for storing raster data  some are more economical than others in terms of storage space  some more efficient in terms of access and processing speed

41. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Issues and trade-offs Maximum resolution determined by the size of grid Less easy to connect tabular (attribute) data to spatial objects Raster data lack topology Regular geometry of raster cells may not accurately reflect the variations of reality

42. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Variable-resolution tessalations Triangulated Irregular Networks (TINs) Alternative to regular raster for terrain modelling Developed in 1970s Can build surfaces from irregular arrays of point elevation data Many commercial GIS now offer TIN capabilities.

43. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Topic 4: Coordinates, Datums, and Projections

44. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Spherical Coordinates Spherical “grid” is called a graticule Latitude references north and south Longitude references east/west Line of constant latitude is a parallel Line of constant longitude is a meridian Meridians converge at the poles Latitude range: 0 to 90 degrees north and south Longitude range: 0 to 180 degrees east and west 0º Latitude Prime Meridian 0º Longitude Equator 90º N Latitude 90º S Latitude Southern Hemisphere Northern Hemisphere Eastern Hemisphere Western Hemisphere 90º W Longitude 0º Longitude 180º Longitude 90º E Longitude

45. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Spherical Coordinates A spherical coordinate measure is expressed in degrees (º), minutes (‘) and seconds (“) 1º = 60’ = 3,600” ; 1’ = 60” Expressed as: ddd mm ss N/S, ddd mm sss E/W Note the convention is to express latitude (y) before longitude (x), but computer environments use x,y In most digital environments, degrees, minutes and seconds are converted to decimal degrees: degrees + (min/60) + (sec/3600) Harrisburg International Airport is: 40º12’N, 76 º45’W, or 40.20N, 76.75W

46. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Spherical Coordinates Eastern and Northern Hemisphere: +x, +y Eastern and Southern Hemisphere:+x, -y Western and Northern Hemisphere: -x, +y Western and Southern Hemisphere:-x, -y

47. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Cartesian Coordinates X axis Y axis 0,0 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 (2.0,3.0) (4.5, 4.5) (7.0,2.0)

48. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Horizontal Datum North American Datum of 1983 an earth centered datum where the center of the spheroid is the center of the earth based on the Geodetic Reference System of 1980 (GRS80): a better approximation of earth’s true size and shape. twice as accurate as the NAD27: resulted in controls shifted up to 100 meters North American Datum of 1927 A local datum centered on the Meades Ranch in Kansas. Surface of ellipsoid was tangent to the Meades Ranch 300,000 permanent control network Clarke 1866 spheroid used to define the shape and size of the earth Meades Ranch Kansas Earth Center Clarke 1866 Center Clarke 1866 Spheroid GRS80 Spheroid Meades Ranch Kansas Earth Center Clarke 1866 Center Clarke 1866 Spheroid GRS80 Spheroid NAD 1927 DATUM NAD 1983 DATUM

49. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Vertical Datum North American Vertical Datum of 1988 1929 datum adjusted based on more precise measurements of geoid shape and mean sea levels. some bench mark heights changed up to 2 meters, but heights between adjacent benchmarks changed < a few millimeters provides better geoid height definitions in order to convert earth centered GPS derived heights National Geodetic Vertical Datum of 1929 vertical datum based mean sea level as determined by years of observations at tidal gauging stations 585,000 permanently monumented vertical benchmarks interconnected by leveling Vertical Datum (mean sea level) Land Mass Sea Floor Sea Level

50. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Projections To represent a spherical model of the earth on a flat plane requires a map projection! Projection

51. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Map Projections Z = rotational axis Y X o a b a Spheroid: a three-dimensional geometric surface generated by rotating an ellipse about one of its axes. It provides an approximate model of the earth’s shape, the first step in constructing a projection

52. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Map Scale Options to deal with minimum mapping unit size at desired design scale Adopt a larger map scale for the source  Increased cost for acquisition  Increased storage for larger data volume Convert area features to points or lines  Evidence of feature is retained  Inconsistency in feature representation  May give up desired metrics (area, perimeter)  May give up overlay analysis options Eliminate small areas  Consistency in feature representation  No evidence of omitted features

53. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Pennsylvania Statewide Projection Projection: Lambert Conformal Conic Spheroid: GRS80 Central Meridian: 77º 45’ 00.0” W (-77.75) Standard parallels: 40º 36’ 10.8” N (40.603) 41º 16’ 33.6” N (41.276) Reference latitude: 39º 19’ 59.9’ N (39.333) Considerations for selecting a statewide projection for Pennsylvania: Pennsylvania’s east/west extent is best suited for a conic projection If you need to preserve area, use Alber’s Equal Area Conic If you need to shape and angle, use Lambert Conformal Conic Select two standard parallels that divide the state into approximately even thirds north to south Select a central meridian that divides the state approximately into equal halves

54. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Map Projections Transform spherical geographic space to a 2-D planar surface. If it is a map, it has been projected! Eliminates need to carry a globe around in the pocket! 2-D Cartesian coordinate space is better suited than spherical coordinates when conducting traditional surveys, mapping, and ground measurements. Ensures a known relationship between map location and earth location

55. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Map Projections CYLINDRICALPLANAR CONIC

56. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Map Projection Distortion Conformal projections Preserve relative angle and shape for small areas, but area is very distorted For any given point, local scale is constant in all directions Used for navigation, meteorological charts Examples: Mercator and Lambert Conformal Conic Equivalent projections Preserve area but shape and angles are very distorted. A coin placed at any location on the map covers the same amount of area Use when area conveys meaning (thematic maps showing density) Examples: Albers Conic Equal Area and Peters Projection

57. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Map Projection Distortion MERCATOR (Conformal) ROBINSON PETERS (Equivalent)

58. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Map Scale Map scale: the relationship between map distance (or display distance) and actual ground distance Scale Calculations: Scale = map distance / (ground distance x conversion factor) To determine map scale when map and ground distances are known:  2.5” on map = 500 feet on ground 2.5/500*12 = 2.5/6,000 = 1:2,400 To determine ground distance when map scale is known:  1:4,800 is same as 1” = 4,800” 1.82” on map: 1 * 1.82 = 4,800*1.82 1.82” = 8,7376” = 728’

59. Some of this material was presented by Bruce Stauffer, Advanced Technology Solutions, Inc., and Todd Bacastow, Penn State. Map Scale Small Scale Maps Large denominator in RF (1:14,000,000) Maps of continents and world maps Medium Scale Maps Medium denominator in RF (1:24,000) USGS Topographic Quadrangles Large Scale Maps Small denominator in RF (1:2,400) Tax maps, utility maps The smaller the number in the denominator, the larger the map scale ½ is “larger” than ¼ and ¼ is “smaller” than ½