(GEO455) Unit 7: Representations & Classifications

What the difference between a visualization and a cartographic representation?

Cartographic representation uses maps, Visualization is broader concept 

What do thematic maps do?

What two main purposes do thematic maps serve?

Represent one or two variables in map form

Analysis of data ; Presentation of data

What kind of data is used in Cartographic Classification?

Give 3 examples.

What levels of measurement can be used?

Quantitative data

Counts, measurements, calculations

Ordinal, interval, and ratio 

How many categories should we use in Cartographic Classification?

3 to 7

Choropleth maps use an existing _______, a type of enumeration unit.

They use color or shading to show ______ of one or two variables.

System of boundaries 

Spatial variation 

Enumeration units use the ______ of geographic units to determine the ______ represented.

Boundaries

Area

Name 2 cartographic reasons that cause maps to look different even if they depict the same variable.

• Different break values

• Different levels of spatial aggregation

• Data normalization

Classifying data refers to the process of placing data into ______ that have similar _______.

Groups

Characteristics or values

What are the 3 major types of data classifications?

Natural breaks (Jenks)

Quantiles/Quartiles

Equal Intervals

Natural breaks groups together ________ in order to maximize ________.

Similar values

Differences between classes

Quantiles places a _______ of values in each class.

An equal number 

Equal Intervals divides values into groups that contain a _____ of values.

When would you avoid using this classification?

An equal range

If data contains outliers 

What’s the preferred color progression used in choropleth maps?

Single hue progression

What are 2 of the other 4 color progressions?

1) Blended hue progression

2) Bipolar hue progression 

3) Full spectral color progression 

4) Value progression

Define hue, value, and saturation.

Hue is the color wavelength

Value is the color’s shade

Saturation is a color’s intensity

What are the primary colors?

What are the pigments used in printing and painting?

Red, green, blue (RGB)

Cyan, magenta, yellow (CMY)

What term describes the following phenomenon:

When a color is surrounded by another color, it appears tinged by the surrounding color

Simultaneous contrast

What are 2 things both Cartograms and Choropleth maps use?

What kind of map are Cartograms and Choropleth maps?

Area symbols ; Spatial units 

Thematic maps

Unlike choropleth maps, cartograms use the spatial unit to represent ______, and not a _______.

What two aspects of spatial units are sacrificed for sake of visual impact?

Values being mapped ; not a classification scheme 

Area and shape

Cartograms have the strongest visual impact when the value is substantially ______ absolute area

Disproportionate

Contiguous cartograms maintain the _____ of neighboring areas while distorting their shapes.

Noncontiguous cartograms maintain the ______ of areas, but produce ____ between the areas.

Adjacency 

Shape ; Gaps

Data Normalization is the process of ________.

What’s the goal?

An example of this is _____.

Density is calculated by _______.

Dividing one numeric attribute value by another

Minimize differences in values

Density

Dividing total population by total area