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spsurvey (version 4.1.4)

grtspts: Select a Generalized Random-Tesselation Stratified (GRTS) Sample of a Finite Resource

Description

This function select a GRTS sample of a finite resource. This function uses hierarchical randomization to ensure that the sample will include no more than one point per grid cell and then picks a point in selected cells.

Usage

grtspts(ptsframe, samplesize = 100, SiteBegin = 1, shift.grid = TRUE,
  do.sample = TRUE, startlev = NULL, maxlev = 11)

Arguments

ptsframe

The sf object containing attributes: id, x, y, mdcaty, and mdm.

samplesize

Number of points to select in the sample. The default is 100.

SiteBegin

First number to start siteID numbering. The default is 1.

shift.grid

Option to randomly shift the hierarchical grid. The default is TRUE.

do.sample

Option to select a sample, where TRUE means select a sample and FALSE means return the entire sample frame in reverse hierarchical order. The default is TRUE.

startlev

Initial number of hierarchical levels to use for the GRTS grid, which must be less than or equal to maxlev (if maxlev is specified) and cannot be greater than 11. The default is NULL.

maxlev

Maximum number of hierarchical levels to use for the GRTS grid, which cannot be greater than 11. The default is 11.

Value

Data frame of sample points containing: siteID, id, x, y, mdcaty, and weight.

Other Functions Required

numLevels

determines the number of levels for hierarchical randomization

constructAddr

constructs the hierarchical address for sample points

ranho

constructs the randomized hierarchical address for sample points

pickGridCells

selects grid cells that get a sample point

pickFiniteSamplePoints

pick sample point(s) from selected cells