Pitfalls of spatial data

Question 1

Spatial autocorrelation diagnostic measures

Answer 1

joins count statistics
moran’s I
geary’s C
variogram cloud

Question 2

Spatial autocorrelation structure

Answer 2

spatial variation across a study area

Question 3

First order spatial variation

Answer 3

occurs when observations across a study region vary from space due to changes in the underlying properties of the local environment

Question 4

Second order spatial autocorrelation

Answer 4

due to local interaction effects between observations

Question 5

MAUP

Answer 5

the same basic data yield different results when aggregated in different ways

Question 6

MAUP components

Answer 6

scale effect

zoning effect

Question 7

MAUP scale effect

Answer 7

consequence of spatial aggregation

Question 8

MAUP zoning effect

Answer 8

results from the multitude of zoning schemes that could be constructed and used at any given scale

Question 9

Boundary issues in statistics

Answer 9

simpson’s paradox

Question 10

Boundary issues in geostatistics

Answer 10

change of support problem

Question 11

Boundary issues in geography

Answer 11

MAUP

Question 12

Boundary issues in sociology

Answer 12

ecological fallacy

Question 13

Ecological fallacy

Answer 13

when its inferred that data for areas under study can be applied to individuals in that area
relationships at one geographic scale are not necessarily true at other geographic scales

Question 14

Four common statistical ecological fallacies

Answer 14

confusion between ecological correlations and individual correlations
Confusion between group average and total average
Simpson’s Paradox
Confusion between higher average and higher likelihood

Question 15

Confusion between ecological correlations and individual correlations

Answer 15

the correlation between individual variables is deduced from the correlation of the variables collected for the group to which those individuals belong

Question 16

Confusion between group average and total average

Answer 16

the average for a group is approximated by the average in the total population divided by the group size

Question 17

Simpson’s Paradox

Answer 17

when comparing two populations divided in
groups of different sizes, the average of
some variable in the first population can be
higher in every group and yet lower in the
total population

Question 18

Confusion between higher average and higher likelihood

Answer 18

Higher average implies higher likelihood, e.g. the ecological fallacy results from incorrectly assuming that individuals in wealthier states are more likely to be
wealthy

Question 19

Preventing ecological fallacy

Answer 19

Be aware of the process of aggregating or disaggregating data
may conceal the variations that are not visible at the larger
aggregate level

Question 20

Scale implications

Answer 20

anticipate influence of geography
assume not all locations will respond in the same way and responses will show spatial pattern
sampling should be dispersed

Question 21

Non-uniformity of space

Answer 21

spatial features are not evenly distributed

Question 22

Edge effects occurrence

Answer 22

where an artificial boundary is imposed on a study

Question 23

Edge effects

Answer 23

features near boundary have fewer neighbors and are less reliable

Question 24

Handling edge effects

Answer 24

use core study area
buffer study area
vary weights for features near boundary