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Calculate and view Getis-Ord statistic

Source: R/getis_ord_stats.r
getis_ord_stats.Rd

Wrapper function to calculate global and local Getis-Ord by discrete area

Usage

getis_ord_stats(
  dat,
  project,
  varofint,
  zoneid,
  spat,
  cat,
  lon.dat = NULL,
  lat.dat = NULL,
  lon.spat = NULL,
  lat.spat = NULL
)

Arguments

dat

Primary data containing information on hauls or trips. Table in the FishSET database contains the string 'MainDataTable'.

project

String, name of project.

varofint

Numeric variable in dat to test for spatial high/low clustering.

zoneid

Variable in dat that identifies the individual zones or areas. Define if exists in dat and is not named `ZoneID`. Defaults to NULL.

spat

Spatial data containing information on fishery management or regulatory zones. See load_spatial.

cat

Variable in spat defining the individual areas or zones.

lon.dat

Longitude variable in dat.Require if zoneid is not defined.

lat.dat

Latitude variable in dat. Require if zoneid is not defined.

lon.spat

Variable or list from spat containing longitude data. Required for csv files. Leave as NULL if spat is a shape or json file.

lat.spat

Variable or list from spat containing latitude data. Required for csv files. Leave as NULL if spat is a shape or json file.

Value

Returns a plot and table. Both are saved to the output folder.

Details

Calculates the degree, within each zone, that high or low values of the varofint cluster in space. Function utilizes the localG and knearneigh functions from the spdep package. The spatial input is a row-standardized spatial weights matrix for computed nearest neighbor matrix, which is the null setting for the nb2listw function. Requires a data frame with area as a factor, the lon/lat centroid for each area, the lat/lon outlining each area, and the variable of interest (varofint) or a map file with lat/lon defining boundaries of area/zones and variable of interest for weighting. Also required is the lat/lon defining the center of a zone/area. If the centroid is not included in the map file, then find_centroid can be called to calculate the centroid of each zone. If the variable of interest is not associated with an area/zone then the assignment_column function can be used to assign each observation to a zone. Arguments to identify centroid and assign variable of interest to area/zone are optional and default to NULL.

Examples

if (FALSE) {
getis_ord_stats(pcodMainDataTable, project = 'pcod', varofint = 'OFFICIAL_MT_TONS',
  spat = spatdat, lon.dat = 'LonLat_START_LON', lat.dat = 'LonLat_START_LAT', cat = 'NMFS_AREA')
}