Presentation on theme: "Geographic Communication Today Harvard Extension School ISMT-E155 Jeff Blossom, Instructor Lecture 10: How to Lie with Maps 1."— Presentation transcript:
Geographic Communication Today Harvard Extension School ISMT-E155 Jeff Blossom, Instructor Lecture 10: How to Lie with Maps 1 April 27, 2011
Geographic Communication Today 4/27/2011 5:30 – 6:00 How to Lie with Maps, cartographic deception 6:00 – 6:15 5 minute paper exercise 6:15 – 6:45 Animation / export to KML demo 6:45 – 7:10 Final project grading criteria, course summary, future possibilities. 7:10 – 7:30 – Work on final projects / questions 2
3 All maps distort reality: projection
Some cartographic line techniques that make maps more aesthetic, readable, and interpretable. 4
6 London tube system – highly generalized map
7 Map scale determines feature selection - what can be shown on maps 1:24,000 scale – major and minor roads, water detail.
8 Map scale determines feature selection - what can be shown on maps 1:100,000 scale – highways, some major roads Area shown on previous slide
9 Map scale determines feature selection - what can be shown on maps 1:1,000,000 scale – political boundaries, select highways Area shown on previous slide
10 Distortion from reality A line printed to be 1/50 th of an inch wide on a 1:100,000 scale map is the graphic equivalent of 167 feet wide
11 ArcMap natural earth data example
12 Washington, D.C. subway system map– large scale in the middle, smaller scale on the perimeter
13 How can you be confident of a map’s accuracy? National Map Accuracy Standards Formalized in 1941 by the American Society of Photogrammetry and Remote Sensing. Accuracy standards based on the mapping scale used, such as: For a map at 1:24,000 scalethe horizontal accuracy standard requires that the positions of 90 percent of all points tested must be accurate within 1/50th of an inch on the map. At 1:24,000 scale, 1/50th of an inch is 40 feet. The vertical accuracy standard requires that the elevation of 90 percent of all points tested must be correct within half of the contour interval. On a map with a contour interval of 40 feet, the map must correctly show 90 percent of all points tested within 20 feet of the actual elevation. "This map complies with National Map Accuracy Standards."
14 Precision – how close measurements are to each other. - Reliant on measuring technique and method Accuracy – how close measurements are to their actual positions on Earth. Determined by the mapping scale and technique used.
15 Accuracy – how close measurements are to their actual positions on Earth. To determine an “actual position on earth”, a datum must be used. Datum – a common reference model, for example WGS local benchmarks can also be considered datums. Horizontal datum (global) – references locations in terms of x,y (longitude, latitude) as measured from the center of the Earth. Vertical datum (global) – references locations in terms of x,y,z (longitude, latitude, elevation) as measured from the center of the Earth. Recreational GPS receivers are commonly accurate to +/- 30 feet horizontally, but only +/- 100 feet vertically. Why?
Horizontal vs. Vertical accuracy Horizontal position location is measured using a regular, neat wireframe mesh extending from the center of the Earth.
Horizontal vs. Vertical accuracy While Horizontal position is measured using a regular, neat wireframe mesh extending from the center of the Earth, vertical position measurements must be made in reference to the surface of a highly irregular potato-shaped object. The Geoid (Earth shape) exaggerated gravity model as measured by the GOCE satellite Vertical positions locations reference how far a point on the surface is from the center of Earth, or in relation to a sea level.
Horizontal vs. Vertical precision Elevation reference distance
19 Cartographic disinformation - A cold war tactic widely applied by the U.S.S.R. aimed to mislead enemies regarding the true location of cities, major streets, etc. Eventually died off due to expense of maintaining two sets of national maps, and satellite survellience
Mapping blunders – geography altered to fit publication page space.
21 Map traps – deliberate falsifications added to a map. Spurred by competing highway map making companies. Falsifications repeated on competitors maps are proof of copyright infringement. Fictitious towns “goblu” and “beatosu” inserted on roadmap
22 An engineer’s map closely depicting reality may not be desirable for advertising purposes Cartographic fiction is employed to produce a more persuasive map that might entice more riders on the H,S,&N vs. the H,S,&Y railway.
23 Areal aggregation and data classification can dilute and deceive.
24 Symbology, type, and color and can be used to emphasize specific messages/agendas. Color Color connotations can potentially mislead
25 “A good map tells a multitude of little white lies; it suppresses truth to help the user see what needs to be seen. Reality is in 3d, rich in detail, and far too factual to allow a complete yet uncluttered two- dimensional graphic scale model. Indeed, a map that did not generalize would be useless. But the value of a map depends on how well its generalized geometry and generalized content reflect a chosen aspect of reality”
5 minute paper Animation demo Export to KML demo 26
27 Final project logistics, deadlines Presentation slides: Submit to the Final Project Dropbox before 2:00 p.m. Wednesday, May 4th for the 5/4 presenters, 2:00 p.m. on 5/11 for the 5/11 presenters. Posters and Videos: Submit these to the Final Project Dropbox before 5:30 p.m. on Wednesday, 5/11 – for everyone. Posters submitted by 8:00 a.m. on your presentation day will be printed.
28 Final project grading criteria Presentation 10 possible points awarded for effectively covering the following: (1 pt) Project introduction, objective, benefactor (1 pt) Data sources, methodology, workflow (2 pts) Visual examples and explanation of maps created (3 pt) Discussion / results / summary – what went well? What went wrong? How was the product received? What did you learn? (3 pts) Clarity, effectiveness, presentation style Poster OR video + paper 10 possible points awarded for effectively covering the following: (1 pt) Project title, author, date, location / area of interest defined (1 pt) Project Introduction, objective, benefactor, lit review (what similar work has been done before?) (1 pt) Data sources + metadata (1 pt) Methodology (software) and workflow (process) used (3 pts) Discussion / results / summary – what went well? What went wrong? How was the product received? What did you learn? (3 pts) Information presented clearly, organized, formatted properly, and focused on the topic. Maps (on poster or in video) 5 points possible, awarded for: (3 pts) Effectiveness in communicating the topic (2 pts) Adherence to cartographic principles as covered in the course The final project grade is 25% of the total grade, 25 possible points, ½ points allowed. Average of Molly and Jeff’s grades.
29 Course Summary – Objectives hopefully achieved: To learn about the fundamental principles of geography - location, place, regions, human/environment interaction, and movement – and understand why they are important. To obtain an understanding of how the earth and geographic information are modeled in order to represent spatial phenomena that communicates both human and physical concepts and ideas. To understand and apply the cartographic principles of map projection, orientation, scale, layout, symbology, type, and color, to produce informative maps of publishable quality. To gain experience using a variety of geographic information software programs, to be able to effectively convert geographic information into maps, presentations, and video, and to develop an advanced proficiency using a software of choice. To understand the breadth and depth of the geospatial industry and Geographic Information Systems (GIS).
30 And finally for next week….. Final presentations: Caitlyn Bolton Ann Adelsberger Owen McKenna Karthik Shanmugam Richard Herstein