Description Usage Arguments Details Value See Also Examples
This function stores the information needed to generate a survey design for a line transect survey in an object of class 'pars.design.lt´.
1 | setpars.design.lt(reg, n.transects = 1, n.units = 1, visual.range, percent.on.effort = 1)
|
reg |
object of class 'region´. |
n.transects |
number of transects. Each transect can contain more than one "unit"; this happens if some segments of the transect are not searched. |
n.units |
number of survey units per transect that are searched; if the whole transect is searched this will be 1. |
visual.range |
maximum distance from the path that is searched: the strip half-width. |
percent.on.effort |
percentage of the transect length that is searched. |
Survey design parameters for the line transect method are defined. The design is composed of a set of survey units (lines) that lie along transect paths. The path can consist of survey units and unsurveyed sections. The transects run parallel to the y-axis and the distances between them are the same in any one design. The location of the bottom left of the first path is a (bivariate uniform) random variable. All survey units are the same size and are the same distance apart along the paths.
This function specifies the “rules” to be used in generating a design, and returns them in an object of class ‘pars.design.lt’. It does not generate the design (which involves some randomization); this is done by passing the ‘pars.design.lt’ object to ‘generate.design.lt’, which introduces the random components. The same ‘pars.design.lt’ object passed to generate.design.lt
twice will result in different designs because of this randomness.
Returns an object of class 'pars.design.lt´ which can be passed to the function generate.design.lt
as a parameter, and contains the following objects:
region |
the region over which the survey takes place |
n/transects |
the number of transects |
n.units |
the number of survey units |
visual.range |
visibility of the observer |
percentage.on.effort |
percentage of the transect paths that is actually used for observation |
parents |
details of the WiSP objects passed to the function |
created |
Creation date and time |
generate.design.lt
, plot.design.lt
1 2 3 4 5 6 7 8 9 10 11 12 | lt.reg <- generate.region(x.length = 100, y.width = 50)
lt.dens <- generate.density(lt.reg)
#heterogeneous population
lt.poppars<-setpars.population(density.pop = lt.dens, number.groups = 1000, size.method = "poisson",
size.min = 1, size.max = 30, size.mean = 10, exposure.method = "beta",
exposure.min = 0, exposure.max = 1, exposure.mean = 0.4, exposure.shape = 0.5,
type.values=c("Male","Female"), type.prob=c(0.48,0.52))
lt.pop<-generate.population(lt.poppars)
lt.despars<-setpars.design.lt(lt.reg, n.transects=10, n.units=10, visual.range=4, percent.on.effort=1)
summary(lt.despars)
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