GGH1501 - Learning Unit 2
,Learning Unit 2 (Geographic data: nature, sources and
representation)
The nature of geographic data:
Distinguish between data and information:
Data – unprocessed facts.
Information – data that have been processed in order to add value.
Example – Number of males (2 500) and females (10 000) in a neighbourhood; data
is unprocessed raw data. Using these raw numbers information can be generated
such as the females account for 80% of the population.
Explain the term geographic phenomenon and geographic variable:
Geographic phenomenon:
- any phenomenon of which we can study spatial characteristics such as location,
distribution and variation.
We can distinguish between two types: discrete and continuous:
• Discrete – not present everywhere. Think about sport fields, roads, nature reserves
and dams.
• Continuous – are present everywhere. Think about atmospheric pressure, height
above sea level, temperature.
Geographic variable:
- Measurable property or characteristic of a geographic phenomenon.
- Think of rainfall as a geographic phenomenon, because its characteristics varies
across space. Not all places receive the same amount of rain. The variable can be
the amount of rainfall can be measured at various places to get the quantity of
rainfall and how it varies across space on a certain day or a certain period during the
year.
Establish the nature of geographic data:
Geographic data can be described in terms of:
1. Spatiality:
- At this stage you already know that all geographical phenomena have an absolute
and relative location, a spatial distribution and vary across space.
2. Temporality:
- The location of phenomena as well as their characteristics can vary over time. Thus
it is important that when obtaining data, that it should ideally be for the same moment
or period in time. It would be a futile exercise to compare incidences of HIV/Aids
across Africa if the years during which data were collected in the different countries
,do not coincide.
3. Scale or resolution:
Since the concept of scale has been addressed in Learning Unit 1 and will again be
dealt with later in this learning unit, we only highlight a few crucial aspects here:
•The scale of a map indicates the extent to which reality has been reduced to fit on
the map.
•There is a direct relationship between scale and the level of detail on a map.
•As regards level of detail, consider how literacy levels vary across Africa on one
map, and over South Africa on another map. The map of South Africa is at a higher
level of resolution and thus offers more detail than the map of Africa. In addition, we
cannot infer the literacy levels of provinces in South Africa from the map providing
literacy level per country in Africa. We thus cannot “upgrade” low resolution data to a
higher level of resolution. In contrast, we can use the data on a map providing
literacy levels per province of South Africa to infer the average literacy level that is
displayed for South Africa, and then to display that on a map of Africa. Thus data can
be generalised by “downgrading” it from a higher to a lower level of resolution.
4. Dimensionality:
, 5. Scale of measurement:
Representations of the Earth:
- Maps are most important tool used by geographers to show where things are
located and represent geographic phenomena or situational contexts.
There are a few key points related to maps we should be aware of:
• Maps are scaled, 2D representations of Earth and are reduced and somewhat
,Learning Unit 2 (Geographic data: nature, sources and
representation)
The nature of geographic data:
Distinguish between data and information:
Data – unprocessed facts.
Information – data that have been processed in order to add value.
Example – Number of males (2 500) and females (10 000) in a neighbourhood; data
is unprocessed raw data. Using these raw numbers information can be generated
such as the females account for 80% of the population.
Explain the term geographic phenomenon and geographic variable:
Geographic phenomenon:
- any phenomenon of which we can study spatial characteristics such as location,
distribution and variation.
We can distinguish between two types: discrete and continuous:
• Discrete – not present everywhere. Think about sport fields, roads, nature reserves
and dams.
• Continuous – are present everywhere. Think about atmospheric pressure, height
above sea level, temperature.
Geographic variable:
- Measurable property or characteristic of a geographic phenomenon.
- Think of rainfall as a geographic phenomenon, because its characteristics varies
across space. Not all places receive the same amount of rain. The variable can be
the amount of rainfall can be measured at various places to get the quantity of
rainfall and how it varies across space on a certain day or a certain period during the
year.
Establish the nature of geographic data:
Geographic data can be described in terms of:
1. Spatiality:
- At this stage you already know that all geographical phenomena have an absolute
and relative location, a spatial distribution and vary across space.
2. Temporality:
- The location of phenomena as well as their characteristics can vary over time. Thus
it is important that when obtaining data, that it should ideally be for the same moment
or period in time. It would be a futile exercise to compare incidences of HIV/Aids
across Africa if the years during which data were collected in the different countries
,do not coincide.
3. Scale or resolution:
Since the concept of scale has been addressed in Learning Unit 1 and will again be
dealt with later in this learning unit, we only highlight a few crucial aspects here:
•The scale of a map indicates the extent to which reality has been reduced to fit on
the map.
•There is a direct relationship between scale and the level of detail on a map.
•As regards level of detail, consider how literacy levels vary across Africa on one
map, and over South Africa on another map. The map of South Africa is at a higher
level of resolution and thus offers more detail than the map of Africa. In addition, we
cannot infer the literacy levels of provinces in South Africa from the map providing
literacy level per country in Africa. We thus cannot “upgrade” low resolution data to a
higher level of resolution. In contrast, we can use the data on a map providing
literacy levels per province of South Africa to infer the average literacy level that is
displayed for South Africa, and then to display that on a map of Africa. Thus data can
be generalised by “downgrading” it from a higher to a lower level of resolution.
4. Dimensionality:
, 5. Scale of measurement:
Representations of the Earth:
- Maps are most important tool used by geographers to show where things are
located and represent geographic phenomena or situational contexts.
There are a few key points related to maps we should be aware of:
• Maps are scaled, 2D representations of Earth and are reduced and somewhat
