This function select a GRTS sample of an area resource. The function uses hierarchical randomization to ensure that the sample will include no more than one point per cell and then picks a point in selected cells.
grtsarea(areaframe, samplesize = 100, SiteBegin = 1, shift.grid = TRUE, startlev = NULL, maxlev = 1, maxtry = NULL)
The sf object containing attributes: id, mdcaty and mdm.
Number of points to select in the sample. The default is 100.
First number to start siteID numbering. The default is 1.
Option to randomly shift the hierarchical grid. The default is TRUE.
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.
Maximum number of hierarchical levels to use for the GRTS grid, which cannot be greater than 11. The default is 11.
This argument is depricated.
Data frame of sample points containing: siteID, id, x, y, mdcaty, and weight.
determines the number of levels for hierarchical randomization
constructs the hierarchical address for sample points
constructs the randomized hierarchical address for sample points
selects grid cells that get a sample point
determines feature ID value and clipped polygon area for each feature contained in a selected grid cell
identifies a feature ID from which to select a sample point
selects sample points from an sf object