mackp {gamair} | R Documentation |
This data frame provides a regular grid of values of some predictor variables useful for modelling mackerel egg abundances. Its main purpose is to enable mackerel egg densities to be predicted over a regular spatial grid within the area covered by the 1992 mackerel egg survey (see mack
), using a fitted generalised additive model.
data(mackp)
A data frame with 5 columns. Each row corresponds to one spatial location within the survey area. The columns are as follows:
mack
measurements).mack
data).mack
data.image()
. See the example below.The grid is defined on a series of 1/4 degree lon-lat squares.
Borchers, D.L., S.T. Buckland, I.G. Priede and S. Ahmadi (1997) "Improving the precision of the daily egg production method using generalized additive models". Can. J. Fish. Aquat. Sci. 54:2727-2742.
## example of how to use `area.index' to paste gridded info. ## into a square grid (of NA's) for plotting data(mackp) lon<-seq(-15,-1,1/4);lat<-seq(44,58,1/4) zz<-array(NA,57*57) zz[mackp$area.index]<-mackp$b.depth image(lon,lat,matrix(zz,57,57))