SpatialPixels               package:sp               R Documentation

_d_e_f_i_n_e _s_p_a_t_i_a_l _g_r_i_d

_D_e_s_c_r_i_p_t_i_o_n:

     defines spatial grid by offset, cell size and dimensions

_U_s_a_g_e:

     GridTopology(cellcentre.offset, cellsize, cells.dim)
     SpatialPixels(points, tolerance = 10 * .Machine$double.eps)
     SpatialGrid(grid, proj4string = CRS(as.character(NA)))
     coordinatevalues(obj)
     points2grid(points, tolerance)
     getGridIndex(cc, grid, all.inside = TRUE)
     getGridTopology(obj)
     areaSpatialGrid(obj)

_A_r_g_u_m_e_n_t_s:

cellcentre.offset: numeric; vector with the smallest coordinates for
          each dimension

cellsize: numeric; vector with the cell size in each dimension

cells.dim: integer; vector with number of cells in each dimension

  points: coordinates, object of class SpatialPoints-class 

    grid: grid topology; object of class GridTopology-class

tolerance: precision, used to which extent points are exactly on a grid

proj4string: object of class CRS-class

     obj: object of class or deriving from SpatialGrid-class

      cc: numeric matrix with coordinates 

all.inside: logical; if TRUE and 'cc' points fall outside the grid
          area, an error message is generated; if FALSE, NA values are
          generated for such points 

_V_a_l_u_e:

     GridTopology returns a value of class GridTopology-class;
     SpatialGrid returns an object of class SpatialGrid-class

     'coordinatevalues' returns a list with the unique x-coordinates,
     the unique y-coordinate, etc. instead of the coordinates of all
     grid cells

     SpatialGrid returns an object of class SpatialGrid-class. 

     points2grid returns the GridTopology-class from a set of points.

     getGridIndex finds the index of a set of point coordinates in a
     given grid topology, and depending on 'all.inside' setting,
     generates NA or an error message if points are outside the grid
     domain.

     getGridTopology returns the slot of class GridTopology-class from
     obj.

     areaSpatialGrid returns the spatial area of (the non-missing
     valued cells of) the grid. For objects of class
     SpatialGridDataFrame-class the area refers to cells where any (one
     or more) of the attribute columns are non-missing valued.

_N_o_t_e:

     SpatialGrid stores grid topology and may or may not store the
     coordinates of the actual points, which may form a subset of the
     full grid. To find out or change this, see fullgrid.

_A_u_t_h_o_r(_s):

     Edzer J. Pebesma, e.pebesma@geo.uu.nl

_R_e_f_e_r_e_n_c_e_s:

_S_e_e _A_l_s_o:

     SpatialGrid-class, SpatialGridDataFrame-class,

_E_x_a_m_p_l_e_s:

     x = GridTopology(c(0,0), c(1,1), c(5,4))
     class(x)
     x
     summary(x)
     coordinates(x)
     coordinates(GridTopology(c(0,0), c(1,1), c(5,4)))
     coordinatevalues(x)

