rewrite zerodist in C, which does not require the full distance matrix (memory limitation!)

[ on a SpatialGridDataFrame, omitting 1 row & 1 column does not work correctly.

document and examples on [ for SpatialPixels.

rbind for Points, Pixels, lines & polygons?

coerce:
	SpatialRings <---> SpatialLines
	SpatialLines ---> SpatialPointsDataFrame, adding Sline.ID, Slines.ID and Line.ID

rgdal interfacing (in rgdal? spgdal?)

spplot: draw image as background or on top (transparent)
	start with colour indexed images; use grid.rect, see panel.levelplot

Higher-dimensional grids: drop dimension after selection? (now fails)
check for dim > 3 for SpatialPoints and SpatialGrid
check points and grids with more than three dimensions.

document methods for SpatialRings[DF] class

write dist(a, b, c("Euclidian", "squared", "Manhattan", "bbox", "greatcircle")) 
	generic/methods?

spplot:
- document sp.layout argument, and layout.north.arrow(), layout.scale.bar()
- spplot(meuse) # takes ages to create legend of inft. length -- check e.g. types!!
- generate grid lines, following lat/lon or projected coords

coordinates(spdf)=~x+y # give a more useful error message

matrix -> grid coercion: present?

sp.layout argument to plotting functions, to draw a background for
spatial plots (e.g. with a grid, lines, polygons, point symbols, ...)
can we learn & steal from lattice here?

fullgrid(SpatialGrid) should work, as well as fullgrid(SpatialGrid)<-

coordinates(spdf) = ~x+y # catch error; give useful message

For plotting functions (plot, bubble) use a reasonable x/y ratio for
unprojected data (look in maps?), or bail out with an error

find out why does, in S-Plus, 
  for(i in 1:100) { polygon(P4x@polygons[[i]]@coords) }
work, but does plot(P4x) error?

Do we need to set a method here?

clean up this file

subsetting SpatialLines[Xx] and SpatialRings[Xx];
not replicate projection in polygons;
(plotting) polygons with islands; crossing polygons?
SpatialDataPolygons -> SpatialDataFramePolygons

What exactly is the interface?
1 coordinates() gets/sets coordinates
2 [Pp]olygons() gets/sets polygons
3 as.data.frame() gets the data as data.frame

0.4-1 splits proj out of sp and (hopefully) simplifies 20030318 RSB

ToDo S-Plus:
plotting polygons doesn't work yet

do we need "[<-" ?

look at stack() to improve map.to.lev

write article for R-NEWS

draft specification of interfaces:

bbox
coordinates
coordinates<- # 2/3D matrix, char vector, int vector, formula; allow NULL object
polygons
polygons<-

methods for _all_ (?) classes:
	print/show
	plot
	summary
	as.data.frame

manuals:
	SpatialData generic functions
	SpatialDataFrame functions
	SpatialDataFrameGrid functions
	SpatialDataPolygons functions

done: maps -> SpatialDataPolygons; do reverse?
	as(x, "maps") # for SpatialDataPolygons
	look at difference in range between maps() and those of polygon vertexes

test:
	3D data frames
	3D regular grids
	3D: test as.images.SDFG for (x,y), (x,z) and (y,z) slices

S-PLUS portability:
	PACKAGE = ...
	plot(..., asp = 1)
