setpars.design.pl: Specifies Survey Design Parameters for a Plot Sampling...
In dill/wisp: Wildlife Simulation Package (wisp)

Description Usage Arguments Details Value See Also Examples

This function stores the information needed to generate a survey design for a plot survey in an object of class 'pars.design.pl´.

1	setpars.design.pl(reg, n.interval.x = 10, n.interval.y = 10, method = "random", area.covered = 0.05, jitter = "sync")

`reg`	object of class 'region´.
`n.interval.x`	number of intervals into which the x-axis is to be divided for placing plot sampling units.
`n.interval.y`	number of intervals into which the y-axis is to be divided for placing plot sampling units.
`method`	method of positioning plot sampling units in the region. Possible methods are: * ‘random´ for selecting units from the 'n.interval.x’ * ‘n.interval.y’ possible units with equal probability and without replacement (simple random sampling); * ‘regular´ for a systematic survey with one unit in each of the 'n.interval.x’ * ‘n.interval.y’ grid rectangles, with ‘area.covered’ percentage of the survey region sampled; ‘jitter’ determines how units are located within the grid rectangles (see below).
`area.covered`	percentage of the area that is to be covered by the survey units.
`jitter`	method of positioning survey units inside the grid rectangles. Possible methods are * `sync` for positioning the survey units with the same random displacements inside each grid rectangle, * `unsync` for positioning the survey with independent random displacements inside each grid rectangle; in this case the displacements are drawn from the same bivariate uniform distribution for every grid rectangle.

Survey design parameters for the plot sampling method are defined. The design is composed of a set of ‘n.interval.x’ * ‘n.interval.y’ survey units (lines), which total ‘area.covered’ percentage of the whole survey area. The method of locating the units is specified using the parameters ‘method’ and ‘jitter’ (see above). To implement the design, the region is divided into ‘n.interval.x’ * ‘n.interval.y’ gridrectangles of the same size. Survey units are then positioned in the rectangles, with each rectangle including at most one survey unit. The size of the units depends on ‘area.covered’. All animals within the survey units are detected on the subsequent survey. This function specifies the "rules" to be used in generating a design, and returns them in an object of class ‘pars.design.pl’. It does not generate the design (which involves some randomization); this is done by passing the ‘pars.design.pl’ object to ‘generate.design.pl’, which introduces the random components. The same ‘pars.design.pl’ object passed to ‘generate.design.pl’ twice will result in different designs because of this randomness.

Returns an object of class 'pars.design.pl´ which can be passed on to the function generate.design.pl as a parameter, and which contains the following objects:

`region`	the region over which the survey takes place
`n.interval.x`	Equal to the object 'n.interval.x' passed to the function
`n.interval.y`	Equal to the object 'n.interval.y' passed to the function
`method`	Equal to the object 'method' passed to the function
`percentage.area.covered`	Equal to the object 'area.covered' passed to the function
`jitter`	Equal to the object 'jitter' passed to the function
`parents`	details of the WiSP objects passed to the function
`created`	Creation date and time

generate.design.pl

pl.reg <- generate.region(x.length = 100, y.width = 50)
pl.dens <- generate.density(pl.reg)
pl.poppars<-setpars.population(density.pop=pl.dens, number.groups = 100, size.method = "poisson", 
						size.min = 1, size.max = 5, size.mean = 1, exposure.method = "beta", 
						exposure.min = 2, exposure.max = 10, exposure.mean = 6, exposure.shape = 1)
pl.pop <- generate.population(pl.poppars, seed=456)

pl.despars<-setpars.design.pl(pl.reg, n.interval.x = 10, n.interval.y = 20,method = "random", area.covered = 0.2)
summary(pl.despars)