Introduction to Geographic Information Systems for Science

1. Introduction to Geographic Information Systems for Science Peter Fox GIS for Science ERTH 4750 (98271) Week 2, Tuesday, January 31, 2012

2. Contents • Introductions • Course Outline • Application areas • Logistics and resources • Assessment and assignments • Learning objectives, outcomes • Introduction to GIS for Science • Next class(es)

3. Introductions • Name, major, year • Interests, goals, outcomes • Have you completed any *suggested* prerequisites: • Geography, cartography. • Other spatial analysis. • Mathematics background • Questions

4. Course Outline (tentative) • Week 2 (Jan. 31/Feb 3): Topic 1/2. Introduction to GIS. Map projections and reference systems. Introduction to MapInfo Professional software. GIS data. Preparing data for MapInfo (geocoding, reformatting). Making simple maps. Layering. Querying and selecting data. Producing thematic maps. • Week 3 (Feb. 7/10): Topic 3. Buffering. Registering raster images. Digitizing from screen. • Week 4 (Feb. 14/17): Topic 4. Geocoding with streets/addresses. Simple interpolation (IDW). • Week 5 (Feb 21/24): Topic 5. Introduction to geostatistics. Interpolation techniques continued (trend surfaces, Thiesses polygons, inverse distance weighting, splines) • Week 6 (Feb. 28/31): Topic 6. Interpolation continued (variograms, kriging) • Week 7 (Mar. 6/9): Topic 7. Analysis of continuous surfaces (filtering, slopes, shading) • Mar. 13/15: no classes - spring break • Week 8 (Mar. 20/23): Topic 8. Analysis of errors • Week 9 (Mar. 27/30): Topic 9. Analysis of discrete entities • Week 10 (Apr. 3/6): Topic 10. Graphs, grouping, pie charts • Week 11 (Apr. 10/13): Topic 11. Editing attributes, manipulating objects in MapInfo • Week 12 (Apr. 17: no class) - Grand Marshall week (Apr. 30) Topic 12. Making a map from scratch, field observations • Week 13 (Apr. 24/27): Prepare for class presentations • Week 14 (May 1/4): Topic 13. Class project presentations

5. Logistics • Class: ERTH 4750 • Hours: 12pm-1:50pm Tuesday, Friday • Location: SAGE 2704 • Instructor: Peter Fox - pfox@cs.rpi.edu or foxp@rpi.edu , x4862 • Contact hours: Tuesdays 2pm-3pm (or by appt) • Contact location: JRSC 1W06 or Winslow 2120 • TA: Max Cane, canem@rpi.edu • Web: http://tw.rpi.edu/web/Courses/GIScience/2012 • Schedule, syllabus, reading, assignments, etc.

6. Assessment and Assignments • Via written assignments with specific percentage of grade allocation provided with each assignment • Via individual oral presentations with specific percentage of grade allocation provided • Via group presentations – depending on class size • Via participation in class (not to exceed 10% of total) – this works by ‘losing’ points by not participating • Late submission policy: first time with valid reason – no penalty, otherwise 20% of score deducted each late day

7. Assessment and Assignments • Reading assignments • Are given almost every week • Most are background and informational • Some are key to completing assignments • Some are relevant to the current week’s class (i.e. follow up reading) • Others are relevant to following week’s class (i.e. pre-reading) • Undergraduates - will not be evaluated on but we will often discuss these in class and participation in these is taken into account • Graduates – are likely to be tested as part of assignments, i.e. an extra question • You will progress from individual work to group work

8. Goals • To provide students an opportunity to learn geospatial applications and tools. • To introduce relational analysis and interpretation of spatial data and presentation on maps. • Introduce spatial database concepts and technical aspects of query languages and geographic integration of graphic and tabular data. • To introduce intermediate aspects of geospatial analysis: map projections, reference frames, multivariate analysis, correlation analysis, regression, interpolation, extrapolation, and kriging. • To gain experience in an end-to-end GIS application via a term project.

9. Learning Objectives • Through class lectures, practical sessions, written and oral presentation assignments and projects, students should: • Demonstrate proficiency in using geospatial applications and tools (commercial and open-source). • Present verbally relational analysis and interpretation of a variety of spatial data on maps. • Demonstrate skill in applying database concepts to build and manipulate a spatial database, SQL, spatial queries, and integration of graphic and tabular data. • Demonstrate intermediate knowledge of geospatial analysis methods and their applications.

10. Academic Integrity • Student-teacher relationships are built on trust. For example, students must trust that teachers have made appropriate decisions about the structure and content of the courses they teach, and teachers must trust that the assignments that students turn in are their own. Acts, which violate this trust, undermine the educational process. The Rensselaer Handbook of Student Rights and Responsibilities defines various forms of Academic Dishonesty and you should make yourself familiar with these. In this class, all assignments that are turned in for a grade must represent the student’s own work. In cases where help was received, or teamwork was allowed, a notation on the assignment should indicate your collaboration. Submission of any assignment that is in violation of this policy will result in a penalty. If found in violation of the academic dishonesty policy, students may be subject to two types of penalties. The instructor administers an academic (grade) penalty, and the student may also enter the Institute judicial process and be subject to such additional sanctions as: warning, probation, suspension, expulsion, and alternative actions as defined in the current Handbook of Student Rights and Responsibilities. If you have any question concerning this policy before submitting an assignment, please ask for clarification.

11. Questions so far?

12. Skills needed • Geography? • Nah, we’ll cover that • Literacy with computers that can load/ run the relevant applications • Yep • Ability to access internet and retrieve/ acquire data • Oh yea • Presentation of assignments • Ditto

13. What is expected • Attend class, complete assignments (esp. reading) • Participate • Ask questions • Work both individually and in a group • Work constructively in group and class sessions

14. Also on the web • Reading assignments – are intended to prepare you for following lectures and may be considered materials for written assignments or project • Assignments will be posted there • Individual • Group • Max is your first contact for assignment questions

15. This course • GIS – in short: computer-based mapping, analysis and retrieve of location-based data • (in) Science, i.e. the process part – but since not all of you are in science, think of it as your application area • Relation to GPS, Remote Sensing

16. GIS in Science (e.g.) • Think about a place (location or feature) or a topic • Form your question (Data Science: Goal) • Find/access/analyze data (most often onto a map • Explore the patterns and related information presented • Enhance the data, add more data or try an alternate analysis • Same question or a new one? • 'Repeat'

17. Introduction to GIS • The importance of information for GIS: information is the heart of GIS. • GIS data: spatial data (mappable data)---referring to space, occupying space, and having cartographic space; non-spatial data --- attribute data

18. Data-Information-Knowledge Ecosystem Experience Data Information Knowledge Creation Gathering Presentation Organization Integration Conversation Context

19. As a consequence … • We’ll need to explore some ‘information’ concepts along the way in this course • If you ever want more… try Xinformatics (offered in the spring, 4xxx/6xxx)

20. Introduction to GIS • GIS infrastructure: hardware, software, data, organization, and people. • GIS generic questions: location, areal relationship (measurement and neighborhood analysis), attributes, patterns, relationships, and trends. • Exercise: http://www.corvallismaps.com/multimap/ Select 18TH and St. and Search, select ‘707’ and look at the returned screen

21. Introduction to GIS • GIS and GPS (see reading also) • Relationships among objects on maps (‘computerized cartography’ plus a lot more) • Purpose of GIS – regroup attributes, perform calculations with built-in functions, edit data, get new data, parse data, select, query,…

22. GIS Objects

23. Practical example • Point: Single coordinate pair (Fire hydrant) • Line: 2 coordinate pairs (Road segment) • Polyline: > 2 points, open figure (Highway) • Region: polygons (State, county) • Groups of regions/points/lines • GIS is the process of dealing with the geographical relationships among these objects

24. Questions for a GIS • What exists at a certain location? • Where are certain conditions satisfied? • What has changed in a place over time? • What spatial patterns exist? • What if this condition occurred at this place? (modelling, hypothesis testing) • (from Dawn Wright, OSU/GIS465)

25. Where is this?

26. So what’s this?

27. Map projections • Representation of the surface of a 3D spherical or ellipsoidal body on a 2D planar map • Who has used • Google Earth? • Microsoft Visual Earth? • NASA WorldWind? • Another?

28. Yes

30. 3D worlds • Great circle - path of minimum distance on surface of sphere, intersection of sphere with plane passing through center of sphere, radius is that of sphere • Small circle - intersection of any plane with surface of sphere, has radius equal to or less than radius of sphere • Map projections (reading): • Always have distortions • User chooses which characteristics to be correct • Distortions depend on scale

31. Properties** to conserve • Area – coin covers the same area anywhere on map (equal area, equivalent, homolographic, authalic, equiareal) • Shape – relative local angles are correct (conformal, orthomorphic) • Scale – no projection conserves scale throughout, equidistant projections give true distances from one point to all others • Direction – azimuthal projection conserves direction from center of map to all other points

32. Projections

34. Other projections • Mercator – lines of constant direction are straight • Gnomonic – great circles are straight lines • Stereographic – great/small circles are circles

35. Types of projections • Cylindrical, conical, planar – can be transformed (unwrapped) to plane without distortion • Conical – meridians radiate from point, parallels are circles • Cylindrical – meridians, parallels are straight lines (eg Mercator) • Planar – meridians radiate from point as straight lines, parallels are circles

36. Types of projections • Parallels – lines of equal latitude; intersection of Earth’s surface with planes that parallel the equator; form small circles • Meridians – lines of equal longitude; planes intersect N and S poles, perpendicular to equator, these are great circles at equally spaced angles, that get close together as one approaches poles • Oblique projections – cylinder that is not parallel to earth’s axis, cone does not intersect earth’s axis, plane not perpendicular to earth’s axis, results in distortions of parallels and meridians

37. Distances on the Earth • At equator only, 1° latitude = 1° longitude. • For sphere (or circle) the total circumference = 2 pi R (pi = 3.1415926…, R = radius) For arc of angle a the arc length is aR. (a is always in radians, for sphere a = 2 pi ) R for Earth = 6370 km so a = 1° = 111.19 km.

38. References for Coordinates • Equator – latitude = 0, positive northward, negative southward • Prime meridian (Greenwich UK) longitude = 0, positive eastward, negative westward • Grids, often made of lon-lat • Cartesian coordinate systems, usually local, designate points by perpendicular distances from axes on a flat map • Y – meridians, positive North (northings) • X – parallels, positive East (eastings)

39. United States • In US we use UTM (Universal Transverse Mercator) and SPCS (State Plane Coordinate Systems) Large regions are divided into zones to decrease distortion.

40. Oblate spheroid Earth is flattened by about f » 1/300 f = (a-b)/a » 1/300 » 22 / 6370 km; a – b » 22 km Earth’s flattening is sufficient to distort maps at 1:100,000 and larger scales.

41. In reality – it’s a Geoid • Earth is not an exact ellipsoid and its real shape is called the geoid. The geoid is the shape the Earth’s surface would have if it was entirely covered with water, in other words, sea level defines the geoid and is an equipotential surface. Local variations in the gravity field cause the geoid to stray from the ellipsoid by ~ ± 100 meters in height. • The geoid is important in surveying because it locally defines vertical (by gravity). Elevations estimated by traditional leveling are relative to the geoid and not to the ellipsoid. Elevations estimated by GPS are relative to the ellipsoid.

42. Reference ellipsoid • Reference ellipsoid requires 2 constants be specified; (1) a and b, (2) a and f, or (3) a and e (e = eccentricity). • There are many different global datums in use today. Satellite-based reference systems e.g. GRS80 and they largely differ in shape of Earth used. • NB. a datum is a reference point or surface against which position measurements are made, and an associated model • Global a and f may be inaccurate for local or even continental scale surveying. Local values used to increase local accuracy.

43. Reference ellipsoid • NAD83 (and 27, the North America Datum) terrestrial and space-based WGS84 (and 72, 64 and 60 of the World Geodetic System) is being replaced by GPS-based reference system • Perhaps even a ‘moving’ reference frame like ITRF96 (International Terrestrial Reference Frame) in which points are given initial positions and velocities • OSGB36 of the Ordnance Survey of Great Britain • ED50, the European Datum • Australians, everyone…

44. Latitude for an ellipsoid • A = geographic (geodetic) latitude, • B = geocentric latitude • A is slightly greater than B, at poles and (recall) equator A = B

45. Huh? Geodetic/geocentric? • It is important to note that geodetic latitude is different from geocentric latitude. • Geodetic latitude is determined by the angle between the normal of the spheroid and the plane of the equator, whereas geocentric latitude is determined around the center

46. Summary • GIS relies on basic elements (review) • Information and Science • Having seen this simple introduction be thinking of how to use GIS for Science, i.e. • What exists at a certain location? • Where are certain conditions satisfied? • What has changed in a place over time? • What spatial patterns exist? • What if this condition occurred at this place? (modelling, hypothesis testing) • (from Dawn Wright, OSU/GIS465)

47. Reading for this week • GPS • Map projections • Georeference systems • MapInfo User Guide and other docs • We will discuss (and install, work with) these on Friday (3rd)

48. Next classes • Fri class was to be install MapInfo / Map Basic • Start working with it, ask questions… • In preparation – see the notes that Max put together (under reading)