Data Linkage and Thematic Mapping

Question 1

Name 4 sources of geographic data

Answer 1

− Some free with GIS software or internet
− Data provision companies (expensive!)
− National services for Higher education and Research
− UKBORDERS: ways of extracting and downloading boundary datasets

Question 2

About the census

Answer 2

− Cross-sectional snapshot of population on single date
− Source of secondary data (Official Statistics)
− Can be examined at several geographical levels
− Total (nearly!) enumeration (count) of national population
− Compulsory completion, require ‘willing co-operation’
− Coverage is consistent (all households asked same questions)
− Coverage comprehensive (enumerators try very hard to ensure completion/response)
− Decennial census since 1801 (2011 Census = 21st and last!), no Census 1941 (1966: mid-term sample Census)
− Confidentiality is protected, criminal offence to disclose information about identified individuals
− Released in ‘super output areas’ = 300 people.
− Costs a lot (£480m)

Question 3

Name 5 uses of the census

Answer 3

− Info about population, housing, employment, education
− Re-calibration of mid-year population estimates
− Inform more than £50 billion of local authority expenditure per annum
− Business can assess markets and locate new offices
− Useful source for student dissertations/projects

Question 4

How can you access the census?

Answer 4

− CASWEB- digital boundary data with attribute data for 1991 and 2001
− InFuse- select a particular topic and then filter out what is required (2001 and 2011)

Question 5

What is Metadata? And the 4 things it shows

Answer 5

Descriptive information about data (Content, Quality, Condition, Origin)

Question 6

Why do we need metadata?

Answer 6

It is important for the integrity of any analysis

Question 7

What is Mapping?

Answer 7

Linking of geographic and attribute data

Question 8

Name the 3 types of Thematic Mapping

Answer 8

Chloropleth, Proportional Symbols, Dot maps

Question 9

Objective of Chloropleth Maps

Answer 9

Symbolise magnitude of statistics for areas

Question 10

Key points about chloropleth maps

Answer 10

− Use darker shading for higher values and light shading for lower values
− Sliding scale (dark > light)
− Avoid shades that are too similar
− Bright colours often interpreted as higher values
− Avoid solid white shading = no data

Question 11

When deciding on class Intervals… 4

Answer 11

−	Need to specify number of classes and class interval used (5 usually maximum, 4 is common)
Equal count
−	The same number of records/areas/zones in each class
Natural break 
−	Sometimes data is clustered into distinct groups so the GIS will assign classes based on these clusters
Standard deviation 
−	Middle range breaks at mean of data and then each class is on SD above or below.
Quartiles/ Quintiles where the class breaks are made for each 20% of people unemployed.

Question 12

Problems of Chloropleth Maps

Answer 12

− Some zones (e.g. wards and output areas) are not natural areas for representing socioeconomic conditions, but we have limited choice.
− Choice of areal units is arbitrary and modifiable
− Information is lost when data are aggregated
− MAUP and Ecological fallacy