Cartography: Thematic Maps

Question 1

Thematic Maps

Answer 1

Maps intended to represent a single attribute or distribution

• Also called special purpose maps
• Intended to deliver a theme!
  ex. ) Cholera map theme was why people are dieing of cholera.

Question 2

What type of cartographic tradtion is Thematic Maps?

Answer 2

They are more the communication tradition!

Question 3

Types of Thematic Maps:

Answer 3

• Dot Density
• Chloropleth
• Graduated symbol
• Flow
• Continous surface
• Cartograms

Question 4

Dot Density, Multivariate

Answer 4

A map in which small symbols of uniform size are used to emphasize the spatial pattern of a phenomena. Each dot above is equivalent to the same quantity while different colours correspond to different variables.

Question 5

Where are dots placed in a dot density map?

Answer 5

Dots are placed randomly within an enumeration zone and are only used to indicate that a specified value of some variable exists in the general area.

Question 6

What is the map symbol in a dot density map?

Answer 6

The dot.

Question 7

What is the unit of analysis on a dot density map?

Answer 7

Unit of analysis for dot density maps is area!

Question 8

What is included and not included in a dot density map?

Answer 8

• No scale bar
• No North arrow
• Every dot is same size and represents same size
• The individual location of symbol is not important
• Symbols are placed randomly within the unit of analysis.

Question 9

Chloropleth map:

Answer 9

A map in which enumeration units (or data collection units) are shaded with an intensity proportional to the data values associated with those units.
- Has colours, different hues!

Question 10

How can you find the unit of analysis on a choropleth map?

Answer 10

The Unit of analysis is the symbol!
ex.) Symbol= Provinces
Area of study= Canada
Unit of analysis= Provinces.

Question 11

Proportional symbol map:

Answer 11

Points are scaled in proportion to the magnitude of data occuring at point locations, such as using circles of varying sizes to represent urban pop.
The symbol varies in size and can be of any type the map maker wishes, in this case the symbol is the wine glass.
- Every unique value gets a unique size. legend has 2 or 3
ex.) Area of study: Toronto
Unit of Analysis: Neighborhood
Symbol: Circle

Question 12

What does a cartographer need to keep in special mind about when making a Proportional symbol map?

Answer 12

The size of the symbol! Some mapping packages will use the area as the proportional variable, but some use other values, such as the diameter of the circle.

Question 13

Graduated Symbol Map

Answer 13

The Number of symbol sizes is set by the categories in legend. Legend has more than 3.

Question 14

Flow Maps:

Answer 14

Flow maps are used to represent data that deals with linear data related to movement of something from one place to another (migration, shipping).
- Different properties of lines and symbols can be used to present variables. Line thickness can indicate the size (magnitude) of the flow, while the arrow direction can indicate direction of the flow.

Question 15

Cartogram Map

Answer 15

a map in which areas are given spatial values (size) as the symbol property, based on the measure of a non-spatial attribute in that area. Usually the areas are uniform (farmlands) but can also be non uniform (provinces)
The symbol property that is manipulated is the symbol size.
ex.) Area of study=England
Unit of analysis: Square kilometers (the unit of which we get data)
Variable being mapped: Population densities comparing densities.

Question 16

How do we find unit of analysis for Cartogram maps

Answer 16

The unit of which we get data (square km)

Question 17

Isarithmic Maps

Answer 17

Joining values with a line. ex.) rainfall. Paces with the same amount of rainfall will be connected.

Question 18

Generalization with chloropleth mapping is synonymous with….

Answer 18

Classification

Question 19

Population/area=

Answer 19

Population densities

Question 20

Classifying Categorical Data in chloropleth maps.

Answer 20

Features in the same class should be similar and should be symbolized similarly Features in different classes should be dissimiliar and should be symbolized differently.

Question 21

2 Primary considerations when classifying numerical data

Answer 21

1. ) Number of classes on a legend

2. ) Division of classes.

Question 22

Division of data:

Answer 22

Break points are division in the data. Categories are what fall inbetween the break points.

Question 23

Categories of Classification scheme:

Answer 23

1. ) Exogenous schemes
2. ) Arbtrary schemes
3. ) Ideographic schmes
4. ) Serial schemes
5. ) Unclassified schemes

Question 24

Exogenous schemes advantageous vs disadvantageous

Answer 24

ex.) Hunger data classified into classes based on criteria for adequate nutrition.
Advantage: Map can be matched to external criteria
Disadvantage: Does not take into account the data distribution.

Question 25

Arbitrary schemes ADV Vs DIS

Answer 25

• Has equal intervals. Rounded numbers or regular divisions.
  Advantage: Useful when you need to compare a series of maps, easy to interpret and understand and works best with data that has a rectangular distribution
  Disadvantage: Not sensitive to the data distribution (if not rectangular)

Question 26

Ideographic schemes

Answer 26

Take more effort because they are chosen based on some characteristics of the data distribtuon itself.

1. ) Natural Breaks
2. ) Quantiles

Question 27

Serial Schemes advantageous VS Disadvantageous

Answer 27

Advantages:
-Useful for normal bell shaped dsitributions
- Useful when you want to focus on areas that deviate the most or least from “average”
- Useful when data mapped is linked to statistical analyses incuding mean and standared deviation
Disadvantage:
- The mean and standard deviation should be understood by user

Question 28

Unclassified Schemes ADV VS DIS

Answer 28

One symbol for each value
Advantage: Minimizes the amount of generilization and simplification good for seeking patterns.
Disadvantage: Poor for picking out categories.