Data Display Scientific Research Methods in Geography

Chapter 10Feb 9, 2010

Data Display…… is a Graphical Technique for

communication and analysis that depicts data patterns rather than literally describing them.

… allows relevant properties of phenomena to be highlighted and clarified.

… is used by scientists for several purposes including:

Initial data examination Interpret the meaning of data Communicate data and meaning to others.

Guidelines for Designing DisplaysGuiding principles for the design and use of

data displays boil down to one underlying idea: Effective Communication.

Effective Communication means - Communicating a great deal of truthful and relevant information in a manner that is:

Clear Accurate Unambiguous Efficient Aesthetically Pleasing

TablesOrganized lists, arrays, or matrices of data.Show data values directly with numbers.Only minimal use of spatiality.Tables Depict Data in Two Ways:

Distribution Tables Show Frequency

Relative frequency, cumulative frequency Contingency tables

Descriptive Index Tables Shows tendency, variability, relationship

Tables continuedMetric-level data in tables

Grouped into classes or intervals to efficiently communicate the pattern of the data.

“Class Intervals” How many classes are appropriate:

At least 3 or 4 and probably no more than 10 Specific to the data set and what is intended to be

communicated

GraphsPictorial representations of data.The use of spatial properties such as:

Location Size Distance Direction

3 Dictums to follow from table 10.1: Label Clearly and Sufficiently Avoid Uninformative and Content-Free Graphic

Marks Fill the Graph Space with Data Marks

0

5

10

15

Series 3Series 2Series 1

Sales1st Qtr2nd Qtr3rd Qtr4th Qtr

0 1 2 30

2

4

Y-Values

Y-Values

Categ

ory

1

Categ

ory

3048

12

Series 3Series 2Series 1

What Types of Graphs are These? What are their uses?

Examples of Global Warming Graphs

MapsIn this context… maps are graphical displays

that depict earth-referenced features and data.

“Take at least one Cartography Course”Reference Maps:

Depict actual earth surface features as accurately as possible

Locations are encoded with a coordinate system

Thematic Maps Special purpose displays Hybrid “map-graph” that uses geographic space as a

base

Maps always distort the earth’s surface and features.

Generalizations need to be made when creating a map. Not all levels of detail can be depicted on a map.

Symbology and Color schema are important to consider.

Sometimes Distortions are part of the communication.

(http://www.math.yorku.ca/SCS/Gallery/images/cartogram/statecartredblue.png)(http://blogs.sas.com/jmp/uploads/choropleth1.png)

New Trends in Scientific VisualizationInformation Visualization is key to exploratory data

analysis, especially with large spatially and temporally distributed data sets.

Buzzwords: Geo-visualization Spatialization Animations Augmented Reality / Virtual Reality Multisensory display technologies: sonification

tactilizations

Bottom Line: No matter how “gee whiz” the visualization technique is, it needs to meet the requirements of effectively communicating data.

Class ExerciseThink of a Data Display example that you

have created or viewed that is particularly effective. What made it effective?

Can you reproduce it on the white board?