If some people had their way, every map would always include five elements that aid in understanding by whom, why, and when a map was made. However, like all recommendations these five parts are suggestions, not requirements.
The five essential elements of maps are:
Legend (special note re color) Scale
Orientation
Neatline Title
Additional and important elements include:
Name of author Date map published Explanation of purpose Projection
Data sources Gridlines
Review Questions
1. What is the difference between geographic and cartographic repre- sentation?
2. What are the four types of measurements?
3. What do the four types of measurements leave out?
4. What distinguishes vector from raster data in Sinton’s framework?
5. Why are TIN and topology not included in Sinton’s framework?
6. What is the general relationship between scale and accuracy?
7. What does “cartographic communication” refer to?
8. What kinds of measurements are excluded from the established four types?
9. What is controlled in a stream gauge (using Sinton’s concept) 10. How is accuracy a qualitative indicator?
Answers
1. What are the differences between geographic and cartographic rep- resentation?
In essence, geographic representation is the selection of observations, mea- surements, and choices about their coding as attributes and relationships in a database. Cartographic representation is the selection of graphical ele- ments and abstraction of geographic information to communicate for a purpose (or multiple purposes).
2. What are the four types of measurements?
Following the psychologist Stevens, they are nominal, interval, ordinal, and ratio. Important measurements, including radial measurements, are not included in this widely used scheme.
3. How do geographic representation choices determine cartographic representation?
How data is collected and stored as part of the geographic representation process limits the possibilities for making cartographic representations. For example, a multilane highway represented as a single line can never be used to indicate how many lanes of traffic are slowed down by heavy traffic.
4. What distinguishes vector from raster data in Sinton’s framework?
Vector data measures space and controls the attribute; raster data controls space and measures the attribute. Both types of data fix time for the geo- graphic representation.
5. Why are TIN and topology not included in Sinton’s framework?
TIN and topology represent relationships. Sinton’s framework involves space, time, and attributes. Relationships are at most implicit.
6. What is the general relationship between scale and accuracy?
The larger the scale (the smaller the area a map represents), the greater the accuracy can be. The smaller the scale (the larger the area a map repre- sents), the lower the accuracy can be. The main issue here is the possible size of the printed page. More detail can be fit onto a single sheet of paper at a large scale than at a small scale. This does not apply to GI. But because of the continued use of data collection processes used originally for pro- ducing printed maps, scale continues to offer a useful shorthand for assess- ing accuracy.
7. What does “cartographic communication” refer to?
GI and maps ultimately communicate. How they communicate depends on the cartographic representation choices. “Cartographic communication” refers to the ability of GI or maps to communicate for specific purposes.
8. What do databases, in an abstract sense, contain?
Attributes and relationships used for cartographic representation and com- munication.
9. What is controlled in a stream gauge (using Sinton’s concept)?
A stream gauge controls time, measures attribute, and fixes space.
10. How is accuracy a qualitative indicator?
Some parts of accuracy may be quantitative, but assessments of accuracy also depend on the consideration of the potential use of the GI or map, which may be only partially specified, leading to a qualitative assessment of accuracy.
Chapter Readings
Chrisman, N. R. (1997). Exploring Geographic Information Systems. New York: Wiley.
Gould, P. (1985). The Geographer at Work. London: Routledge.
Gould, P. (1989). Becoming a Geographer. Syracuse, NY: Syracuse University Press.
Hartshorne, R. (1939/1956). The Nature of Geography: A Critical Survey of Current Thought in the Light of the Past. Lancaster, PA: Association of American Geogra- phers. [Reprinted with corrections, 1961]
Hartshorne, R. (1958). The Concept of Geography as a Science of Space, from Kant and Humboldt to Hettner. Annals of the Association of American Geographers, 48(2), 97–108.
Monmonier, M. (1991). How to Lie with Maps. Chicago: University of Chicago Press.
Monmonier, M. (1993). Mapping It Out: Expository Cartography for the Humanities and Social Sciences. Chicago: University of Chicago Press.
Monmonier, M. (1994). Spatial Resolution, Hazardous Waste Siting, and Freedom of Information. Statistical Computing and Statistical Graphics Newsletter, 5(1), 9–11.
Monmonier, M. (1995). Drawing the Line: Tales of Maps and Cartocontroversy. New York: Holt.
Web Resources
Geographic representation is an important topic for research in GIScience. See www.
spatial.maine.edu/~max/UCGIS-Rep.pdf
A prominent GIS software producer’s view on geographic representation can be found at www.esri.com/software/arcgis/concepts/gis-data.html
The application of cartographic representation to mapping in Africa offers important insights into pragmatic issues. See www.africover.org/carto_standard.htm
A discussion about changes to cartographic representation helps one to think about connections to geographic representation. See www.questia.com/PM.
qst?a=o&d=5000969871
The U.S. EPA has some interesting materials on the differences between raster and vector at www.epa.gov/region02/gis/gisconcepts.htm
These presentation materials provide a succinct overview of accuracy issues: www.
epa.gov/nerlesd1/gqc/courses/images/kirkland.pdf
Part of an online training course offered by the USGS covers basic database princi- ples in terms of spatial analysis. See http://geology.er.usgs.gov/eespteam/GISLab/Cyprus/
database_modeling.htm
Exercises
1. Geographic Representations: Measurements, Observations, Relationships
Think of some environmental or social issues of which you are aware and consider how to represent them geographically. Take into account how you would measure the observations and relate the measurements (as geographic information) to each other. What measurement types could you use for the observations?
2. Geographic Representations: Considering choices
Starting with the questions provided in the list of choices, consider some of the potential issues in making the geographic representation you started in In-Class Exercise 1 of this chapter. Any issues are valid in this exercise. Write them down and see how they show themselves in the following chapters.
3. Quality and Choices
Based on the discussion of geographic representation, cartographic representation, and the relationships between them and to cartographic communication. Discuss on hand of the example you have worked with for the other in-class exercises, what potential impacts some of your choices can have on quality.
4. EXTENDED EXERCISE: Representations
Objective: Identify different measurements and geographic representations
Overview
A key part of creating and working with GI and maps is identifying the underlying measurements and choices in geographic representations. This can be difficult, but extremely worthwhile.
Instructions
Using maps from the library or Internet sites (e.g., www.davidrumsey.com), identify at least two different thematic maps. Examine the maps and identify the measure- ments, geographic representations, and cartographic representations.
Questions
1. What is the title, subject, and date of the map? Who created the map? Is it part of an atlas, series, or report? Where did you find the map?
2. What alternative measurements could have been made? Explain at least two measurements and the consequences for the map.
3. Is it clear how the measurements are collected? Does it say when and by whom? How is this information (or lack thereof) important for assessing the geographic and cartographic representations?