geosnap.analyze.linc

geosnap.analyze.linc(labels_sequence)

Local Indicator of Neighborhood Change

Parameters:

labels_sequence: sequence of neighborhood labels (n,t)

n areas in t periods first element is a list of neighborhood labels per area in period 0, second element is a list of neighborhood labels per area in period 1, and so on for all T periods.

Returns:

lincs: array

local indicator of neighborhood change over all periods

Notes

The local indicator of neighborhood change defined here allows for singleton neighborhoods (i.e., neighborhoods composed of a single primitive area such as a tract or block.). This is in contrast to the initial implementation in [RAF+11] which prohibited singletons.

Examples

Time period 0 has the city defined as four neighborhoods on 10 tracts:

>>> labels_0 = [1, 1, 1, 1, 2, 2, 3, 3, 3, 4]

Time period 1 in the same city, with slight change in composition of the four neighborhoods

>>> labels_1 = [1, 1, 1, 1, 1, 2, 3, 3, 3, 4]
>>> res = linc([labels_0, labels_1])
>>> res[4]
1.0
>>> res[1]
0.25
>>> res[7]
0.0
>>> res[-1]
0.0

And, in period 2, no change

>>> labels_2 = [1, 1, 1, 1, 1, 2, 3, 3, 3, 4]
>>> res = linc([labels_1, labels_2])
>>> res[0]
0.0

We can pass more than two time periods, and get a “time-wise global linc” for each unit

>>> res = linc([labels_0, labels_1, labels_2])
>>> res[0]
0.25