Strand 2: Data Linkage and Thematic Mapping

Question 1

Example of Attribute data

Answer 1

Census Data

Question 2

How much does the Census cost?

Answer 2

£482m - less than £1 per year

Question 3

Characteristics of Census data

Answer 3

1. Cross-sectional snapshot of population on single data
2. Source of secondary data
3. Can be examined at several geographical levels
4. Total enumeration of national population
5. Confidentiality is protected (Criminal offense to disclose individual data)
6. Decennial since 1801
7. Coverage = Comprehensive
8. Coverage = Consistent (Asked same questions)
9. Completion = Compulsory

Question 4

Why do we need the Census?

Answer 4

1. Useful source for students/ dissertation
2. Provides Authorities with consistent nation/local information about: Population, Housing, Employment, Education etc…
3. Businesses use it to assess markets and location planning
4. Informs more than £50bn of local authority expenditure per annum
5. Re-calibration of mid-year population estimates between censuses.

Question 5

Name 2 online sources of Census Data

Answer 5

1. CASWEB

2. InFuse (New system makes it easier for users)

Question 6

Why is InFuse easier?

Answer 6

1. Find census information which meets their needs
2. Able to understand the meaning and origin of Census info
3. Download Census information in forms that facilitate its use

Question 7

What do all GIS resources need?

Answer 7

Metadata - important for the integrity of any analysis

Question 8

What descriptive information does metadata provide?

Answer 8

1. Content
2. Quality
3. Condition
4. Origin
5. Other characteristics e.g who, where, why

Question 9

What is the primary objective of a Choropleth map?

Answer 9

To symbolise magnitude of statistics for areas

Question 10

What data uses Choropleth maps?

Answer 10

Used for Standardised data e.g rates, densities, percentages (%)
E.g. Rate of various ethnicities in a city region

Question 11

What is the convention for colors on a Choropleth map?

Answer 11

Bright Colors or Darker shading for high values

Question 12

What maps are used for Count Data?

Answer 12

Proportional Symbol Maps - use symbols proportional in size to the values they represent

Question 13

What are Dot Maps?

Answer 13

Where individuals or groups of events are marked with a dot, sees patterns such as clustering e.g John Snow

Question 14

What are the 5 method of selecting class intervals?

Answer 14

1. Equal range - e.g. 1-4, 5-9, 10-14 etc.
2. Equal Count - ensuring the same number of counts in each class interval e.g. 5 data sets in each interval
3. Natural Break - computer assigns classes based on natural clusters
4. Standard Deviation
5. Quartiles - e.g. class intervals created in quintiles, for example a new class interval after 20% people who are unemployed

Question 15

What does choosing intervals make easy to do?

Answer 15

LIE or DISTORT truth

Question 16

What are the disadvantages of mapping?

Answer 16

1. Exaggerates the difference between two areas e.g. a place with a figure of 19.5% and a place with 20.5% are very similar results, but may look v different with 2 different colours
2. Count data misleading as areas vary in both size and population
3. Some geographical areas are v. big and some v. small - therefore v. big areas have a colour dominating a map giving misleading results
4. The default class intervals i.e. Natural Break, can be misleading and incorrectly sorted

Question 17

What are Proportional Symbol Maps?

Answer 17

Size proportional to the value they represent
Mapping COUNT data
E.g. Total number of motor vehicle deaths by county across the UK