irs: Select an Independent Random Sample (IRS)

In mhweber/spsurvey: Spatial Survey Design and Analysis

Description

Select an independent random sample from a point, linear, or areal frame. Frame features must be located in a 1-dimensional or 2-dimensional coordinate system. Sample may be equal probability or unequal probability (either categorical or proportional to an auxiliary variable). May designate panels of sites for surveys over time.

Usage

irs(design, DesignID = "Site", SiteBegin = 1, type.frame = "finite",
  src.frame = "shapefile", in.shape = NULL, sf.object = NULL,
  sp.object = NULL, att.frame = NULL, id = NULL, xcoord = NULL,
  ycoord = NULL, stratum = NULL, mdcaty = NULL, maxtry = NULL,
  shapefile = TRUE, prjfilename = NULL, out.shape = "sample.shp")

Arguments

design	Named list of stratum design specifications which are also lists. Stratum names must be subset of values in stratum argument. Each stratum list has four components: panel named vector of sample sizes for each panel in stratum seltype the type of random selection, which must be one of following: "Equal" - equal probability selection, "Unequal" - unequal probability selection by the categories specified in caty.n and mdcaty, or "Continuous" - unequal probability selection proportional to auxiliary variable mdcaty caty.n if seltype equals "Unequal", a named vector of sample sizes for each category specified by mdcaty, where sum of the sample sizes must equal sum of the panel sample sizes, and names must be a subset of values in mdcaty over number of replacement sites ("oversample" sites) for the entire design, which is set equal to 0 if none are required) Example design for a stratified sample: design=list( Stratum1=list(panel=c(PanelOne=50), seltype="Equal", over=10), Stratum2=list(panel=c(PanelOne=50, PanelTwo=50), seltype="Unequal", caty.n=c(CatyOne=25, CatyTwo=25, CatyThree=25, CatyFour=25), over=75)) Example design for an unstratified sample: design <- list( None=list(panel=c(Panel1=50, Panel2=100, Panel3=50), seltype="Unequal", caty.n=c("Caty 1"=50, "Caty 2"=25, "Caty 3"=25, "Caty 4"=25, "Caty 5"=75), over=100))
DesignID	Name for the design, which is used to create a site ID for each site. The default is "Site".
SiteBegin	Number to use for first site in the design. The default is 1.
type.frame	The type of frame, which must be one of following: "finite", "linear", or "area". The default is "finite".
src.frame	Source of the frame, which equals "sf.object" if the frame is contained in an sf package object, "shapefile" if the frame is to be read from a shapefile, "sp.object" if the frame is obtained from an sp package object, or "att.frame" if type.frame equals "finite" and the frame is included in att.frame. The default is "shapefile".
in.shape	Name of a shapefile containing the frame, which is required when src.frame equals "shapefile". The shapefile name should include the ".shp" extension. If the name does not include that extension, it will be added. The default is NULL.
sf.object	An sf package object containing the frame, which is required when src.frame equals "sf.object". The default is NULL.
sp.object	An sp package object containing the frame, which is required when src.frame equals "sp.object". The default is NULL.
att.frame	Data frame composed of attributes associated with elements in the frame. If src.frame equals "att.frame", then att.frame must include columns that contain x-coordinates and y-coordinates for each element in the frame. If src.frame does not equal "att.frame" and att.frame is not equal to NULL, then an sf object is created from att.frame and the geometry column from the object named "sf.object" that is created by the function. The default is NULL.
id	This argument is depricated.
xcoord	Character string containing the name of the column from att.frame that identifies x-coordinates, which is required when src.frame equals "att.frame". The default is NULL.
ycoord	Character string containing the name of the column from att.frame that identifies y-coordinates, which is required when src.frame equals "att.frame". The default is NULL.
stratum	Character string containing the name of the attribute in sf.object that identifies stratum membership for each feature. If stratum equals NULL, the design is unstratified, and an attribute named "stratum" (with all of its elements equal to the stratum name specified in design) is added to sf.object. The default is NULL.
mdcaty	Character string containing the name of the attribute in sf.object that identifies the unequal probability category for each feature. The default is NULL.
maxtry	This argument is depricated.
shapefile	Option to create a shapefile containing the survey design information, where TRUE equals create a shapefile and FALSE equals do not create a shapefile. The default is TRUE.
prjfilename	This argument is depricated.
out.shape	Name of the output shapefile. The default is "sample.shp".

Value

An object of class SpatialDesign containing the survey design information and any additional attribute variables that were provided. Optionally, a shapefile can be created that contains the survey design information.

Other Functions Required

irsarea

select an IRS sample of an area resource

irslin

select an IRS sample of a linear resource

irspts

select an IRS sample of a finite resource

mdmarea

calculate multidensity-density multipliers for an area resource

mdmlin

calculate multidensity-density multipliers for a linear resource

mdmpts

calculate multidensity-density multipliers for a finite resource

Author(s)

Tom Kincaid [e-mail]

Examples

## Not run: 
  test_design <- list(
    Stratum1=list(panel=c(PanelOne=50), seltype="Equal", over=10),
    Stratum2=list(panel=c(PanelOne=50, PanelTwo=50), seltype="Unequal",
      caty.n=c(CatyOne=25, CatyTwo=25, CatyThree=25, CatyFour=25), over=75))
  test_sfobject <- st_read("test_shapefile.shp")
  test_sample <- irs(design=test_design, DesignID="TestSite",
    type.frame="area", src.frame = "sf.object", sf.object=test_sfobject,
    stratum="test_stratum", mdcaty="test_mdcaty")

## End(Not run)

mhweber/spsurvey documentation built on Sept. 17, 2020, 4:24 a.m.