4.4 Multivariate Local Join Count

Co-location Local Join Count

Multivariate or colocation local join count (2019) works when two or more events happen in the same location (e.g., a city block that is both low-density and commercial, or a parcel that can be single family/multifamily, or owned/rented). It can be used to identify positive spatial autocorrelation. For more information, please read http://geodacenter.github.io/workbook/6a_local_auto/lab6a.html

local_multijoincount()

local_multijoincount() is a PostgreSQL WINDOW function. Please call it with an OVER clause.

Synopsis

Short version:

float[] local_multijoincount(anyarray vals, bytea weights)

Full version:

float[] local_multijoincount(anyarray vals, bytea weights,
    integer permutations, 
    character varying permutation_method,
    float significance_cutoff, 
    integer cpu_threads, 
    integer seed)

Arguments

Name	Type	Description
vals	anyarray	an array of numeric columns that contains the binary values (e.g. 0 and 1) for LISA statistics
weights	bytea	the bytea column that stores the spatial weights information
permutations	integer	the number of permutations for the LISA computation. Default: 999.
permutation_method	character varying	the permutation method used for the LISA computation. Options are 'complete', 'lookup'. Default: 'lookup'.
significance_cutoff	float	the cutoff value for significance p-values to filter not-significant clusters. Default: 0.05.
cpu_threads	integer	the number of cpu threads used for parallel LISA computation. Default: 6.
seed	integer	the seed for random number generator used in LISA statistics. Default: 123456789.

Return

Type	Description
float[]	an array contains 3 values, which are {'local join count', 'pseudo-p value', 'number of neighbors'}

The results do NOT have 'category indicator'.