1. ENV 200610.1 Envisioning Information Lecture 10 – Cartograms: A different way of drawing maps Ken Brodlie kwb@comp.leeds.ac.uk

2. ENV 200610.2 Choropleth Maps Maps have been traditionally drawn to represent area –With topography indicated by shading Increasingly we use maps to represent properties about areas –Here each state is shaded according to density of population –Known as choropleth mapping http://www.cdc.noaa.gov/USclimate/states.fast.html

3. ENV 200610.3 Discuss Strengths and Weaknesses StrengthsWeaknesses

4. ENV 200610.4 Cartograms The cartogram is a response to these issues –Rather than accurately reflect the area and superimpose shading to represent the variable.. –.. Distort the area so as to reflect the variable directly

5. ENV 200610.5 Types of Cartogram Cartograms can be contiguous or non-contiguous –Here is population of California by county as a contiguous cartogram

6. ENV 200610.6 Types of Cartogram.. And now as a non-contiguous cartogram

7. ENV 200610.7 Contiguous and Non-Contiguous Cartograms Here is the US population example in both styles…

8. ENV 200610.8 Perimeter-preservation

9. ENV 200610.9 World Population Cartogram Acknowledgement: Examples taken from Web site of Dr Donald House http://www-viz.tamu.edu/faculty/house/cartograms

10. ENV 200610.10 George Bush – Victory large or small?

11. ENV 200610.11 Types of Cartogram Danny Dorling (recently Professor in Leeds) invented a special type of cartogram using circles of different size http://www.ncgia.ucsb.edu/projects/Cartogram_Central/index.html

12. ENV 200610.12 Dorling Cartograms Try the applet at: http://www.mapresso.com/dorling/dorlingexample.html

13. ENV 200610.13 British county populations evolving…

14. ENV 200610.14 Chernoff Face Cartogram! Acknowledgement: –Last two slides from Cartograms for Human Geography, by D. Dorling, in Visualization in Geographical Information Systems, Wiley.