Creates model formula list for conventional distance sampling using values
supplied in call to ddf
cds(
key = NULL,
adj.series = NULL,
adj.order = NULL,
adj.scale = "width",
adj.exp = FALSE,
formula = ~1,
shape.formula = ~1
)A formula list used to define the detection function model
string "cds"
key function string
adjustment function string
adjustment function orders
adjustment function scale type
formula for scale function
formula for shape function
string identifying key function (currently either "hn" (half-normal),"hr" (hazard-rate), "unif" (uniform) or "gamma" (gamma distribution)
string identifying adjustment functions cos (Cosine), herm (Hermite polynomials), poly (simple polynomials) or NULL
vector of order of adjustment terms to include
whether to scale the adjustment terms by "width" or "scale"
if TRUE uses exp(adj) for adjustment to keep f(x)>0
formula for scale function (included for completeness only only formula=~1 for cds)
formula for shape function
Jeff Laake; Dave Miller