Lecture 8

Describe MAUP

A problem arising from the imposition of artificial units of spatial reporting on continuous geographic phenomena resulting in the generation of artificial spatial patterns

What is ecological fallacy?

A situation that can occur when a research or analyst makes an inference about an individual based on aggregated data for a group

What is a solution to MAUP

Be aware of how sensitive data is to MAUP

What does "basic" raster and vector analysis include?

A class of operations that are fundamental to a wide range of applications and are common in practice

What does MAUP involve?

Data that are spatially aggregated using arbitrary boundaries and affects our ability to quantify apparent relations, statistical or other

What type of data is rare to deal with in terms of spatially aggregated data

Data that is point specific

Give an example of MAUP

Electoral Districts and Voting

What does euclidean distance give and also leave out

Gives the distance but not direction

Where is gerrymandering common

In many countries, sometimes even legal (this is the case for the US)

How is electoral districts and voting an example of MAUP?

It's not just who you vote for, but also where you vote that counts - A different aggregation of US counties into states could have produced a different outcome (in the Al Gore/George Bush care)

Describe spatially aggregated data

Many geographic data are aggregates of data at a more detailed level

Discuss ecological fallacy in terms of stats

Median is a much stronger value than average, because usually the datasets are not normally distributed. They are normally skewed. Therefore, taking an average is not ideal because it would include the outliers

Describe dissolving

Merges points together to create an overlap

Describe Manhattan distance

More like a road network - moves around boundaries

Give some examples of spatially aggregated data

National census, traffic analysis zone, school district, watersheds, pixels

Even though we commonly classify spatial analysis as Vector or Raster...

Often the same analysis can be performed using either model, and many types of analysis involve both raster and vector data

How can we be aware of how sensitive data is to MAUP

Perform a sensitivity analysis to the MAUP by aggregating the data in different ways and seeing if the trends remain in all cases

Describe the Aggregation Effect

Take the number of units, and the same range of the units, and just change when the boundaries are

What are the 2 manifestations that MAUP includes

The Aggregation Effect and The Scale Effect

When dealing with buffering, what are we usually interested in?

The Euclidean (straight line) distance - How the crow flies

What does MAUP stand for

The Modifiable Areal Unit Problem

Describe the Scale Effect

The arbitrary-ness of the number of units you're using

What does vector buffering imply?

The calculation of distance

What is vector buffering?

The creation of a zone of interest around a spatial entity or set of entities

What is buffer width dependent on?

The individual characteristics of each feature

What specifically deals with ecological fallacy the most?

The media - Constantly draws conclusions about research done at one scale and applied it to a different scale

Describe gerrymandering

The practice of setting electoral district boundaries to favour a particular outcome

Why do we carry out analysis on geospatial data?

To uncover important spatial relations, gain understanding about some phenomenon or system, and perhaps to inform some decision

Describe MAUP when using spatially aggregated data

Usually the boundaries between one unit of aggregation and other are arbitrary

What are some buffering variables?

We can buffer points and lines

What is the main question you need to ask when dealing with dissolving

What are we particularly interested in? Do we want to identify some about the actual features/the zone/the whole aggregate data

When is ecological fallacy particularly a problem when dealing with data?

When dealing with data that is negatively skewed

When is ecological fallacy most significant?

When it is downscaled

When do we have to be especially careful for gerrymandering

When we modify the geographic boundaries of voting aggregation areas

What is one thing that is fairly consistent with MAUP?

When you aggregate data, you will have less variability than the underlying data - therefore toy will be able to determine trends in the data

What is one main rule concerning the ecological fallacy

You can't draw individual conclusions on large-scale findings - only at the scale of aggregation