High/Low Clustering Getis-Ord General G
►
Concentrates on high or low values for an entire study area
►
A high value indicates that high values are clustered within the study area
►
A low values indicates that low values tend to cluster
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Z score calculated to determine if the index is significant
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Null hypothesis is still that “there is no spatial clustering of the values”
► Positive
Z-score values mean high values are clustered
► Negative
Z-values mean low values are clustered
► Getis-Ord
values!
is really all about the Z-
Hot Spot Analysis ► This
is Getis-Ord that is mapped.
► Given
a set of weighted data points, this tool identifies those points with values higher in magnitude than you might expect to find by random chance, and vice versa.
► Those
that are statistically significant, a Zscore bigger than 1.96 or less than 1.96 are highlighted.