import(raster)
import(methods)
import(Matrix) 
importFrom(igraph, clusters, E, "E<-", get.shortest.paths, graph.adjacency, shortest.paths)
importClassesFrom(sp, SpatialPoints, SpatialPointsDataFrame,
SpatialPixels, SpatialGrid, SpatialPixelsDataFrame, SpatialGridDataFrame)
importFrom(sp, coordinates, CRS, Line, Lines, SpatialLines)
#importClassesFrom(raster, BasicRaster, Raster)
#importFrom(methods, Ops, Arith, Compare, Logic)
exportClasses(TransitionLayer, TransitionStack, Coords)
exportPattern("^[^\\.]")
exportMethods(show, coerce, Ops, Arith, Compare, Logic, "[", "[<-", accCost, costDistance, geoCorrection, normalize, pathInc, passage, transition, commuteDistance, shortestPath)