Choropleth mapping

Question 1

what does Choro + pleth mean

Answer 1

area + Value

Question 2

what is a Choropleth mapping

Answer 2

mapping techniques which symbolize values applied to area

Question 3

what are the aspatial requirements of choropleth mapping

Answer 3

derived data only
ratios, proportions, percentages, rates, commonly normalized.

Question 4

what are 2 types of discrete areal units

Answer 4

Natural areal units
Artificial areal units

Question 5

what is the MAUP

Answer 5

Data collected in arbitrary space results in simplification an error.
different aggregation of data creates different results

Question 6

what are the effects of size of areal units in Choropleth mapping

Answer 6

• higher aggregation results in higher data loss
• impacts symbolization method
• perceived accuracy/ appearance

Question 7

how does map scale affect Choropleth mapping

Answer 7

• ## smallest units must be visible

Question 8

what is the difference between a choropleth and a chorochromatic map

Answer 8

chorochromatic maps are a form of choropleth but only show nominal area data

Question 9

what are the two types of choropleth maps that show Interval, ordinal, or ratio data

Answer 9

• classless Choropleth map
• range graded choropleth map

Question 10

what is one of the difficult aspects of range Graded Choropleth maps

Answer 10

choosing an effective classification interval

Question 11

what are the six steps of choropleth mapping

Answer 11

1. Judge suitability of data
2. Order data (rank order)
3. Classless or range-graded?
4. Determine # of classes into which to divide data
5. Determine class intervals (class breaks)
6. Determine visual clues to differentiate between classes (Symbology)

Question 12

what data is suitable for choropleth mapping

Answer 12

derved data,
- consider discrete/continuous
- aggregated by area

Question 13

which is better, Range graded or classless choropleth maps?

Answer 13

depends, classless requires high computing power. Range graded is generally convention

Question 14

what is the ideal number of classes

Answer 14

4-6

Question 15

what does fewer classes convery

Answer 15

a louder message

Question 16

what does many classes convery

Answer 16

shows more information, but messy

Question 17

what are the 4 classification schemes we used

Answer 17

natural breaks
Quanitile
Equal interval
Standard deviation

Question 18

How does natural breaks work

Answer 18

based on natural groupings in the dataset

Question 19

how does quantile work

Answer 19

each class contains an equal number of features

Question 20

how doe sEqual interval work

Answer 20

divides the range of attributes into equal sized subregions

Question 21

how does standard deviation work

Answer 21

how much a feature varies from the mean
requires normally distributed data

Question 22

when is class boundaries optimized

Answer 22

minimize variance within class, while maximizing variance between class

Question 23

what does GVF test stand for

Answer 23

goodness Variance Fit test

Question 24

what does GVF show?

Answer 24

it provides a summary statistic about the chosen classification method to show how good the scheme is.

Question 25

what is a nested mean

Answer 25

mean of the data used to divide the data into two classes, values above and below the mean.

Question 26

what is a skewness, Positive and negative

Answer 26

shows how the data is distributed, Positive skew is more 0, negative skew is greater values

Question 27

what is a single hue progression

Answer 27

a symbolization method that only involves one colour, typically white - full saturation

Question 28

what is a Bipolar Progression

Answer 28

using two colours to symbolize features, usually fully saturation one colour –> white –> full saturation another colour.

Question 29

what is a Bivarite choropleth map

Answer 29

a map choropleth map that has two variables.
square table to show intensity

Question 30

what is a good projection for Choropleth mapping

Answer 30

should use an equivalent projection