Only "x", "y" "n" and "pos" are required in col
.
If "id" is not specified, a numzrical identifier will be automatically created.
proj
defines projection used by data
. It could be a character string
corresponding to a PROJ.4 projection (see http://trac.osgeo.org/proj/
for more details) or an object of class CRS
{sp}.
If the projection of boundary
is defined in a slot called proj4string
,
boundary
will be projected according to proj
. If the slot proj4string
is missing, boundary
will be considered to be already in the same projection as proj
.
If boundary
is not defined (NULL
), a considered corresponding to minimal
and maximal coordinates of data
will be used.
boundary
could be the result of the function create.boundary
.
It's not possible to change projection of data
with as.prevR
.
Use changeproj
instead.