Rlogo                   package:sp                   R Documentation

_R_l_o_g_o _j_p_e_g _i_m_a_g_e

_D_e_s_c_r_i_p_t_i_o_n:

     Rlogo jpeg image data as imported by 'getRasterData' in the rgdal
     package

_U_s_a_g_e:

     data(Rlogo)

_F_o_r_m_a_t:

     The format is: int [1:101, 1:77, 1:3] 255 255 255 255 255 255 255
     255 255 255 ...

_E_x_a_m_p_l_e_s:

     ## Not run: 
     library(rgdal)
     logo <- system.file("pictures/Rlogo.jpg", package="rgdal")[1]
     x <- GDAL.open(logo)
     gt = .Call('RGDAL_GetGeoTransform', x, PACKAGE="rgdal")
     data <- getRasterData(x)
     GDAL.close(x)
     ## End(Not run)
     data(Rlogo)
     d = dim(Rlogo)
     cellsize = abs(c(gt[2],gt[6]))
     cells.dim = c(d[1], d[2]) # c(d[2],d[1])
     cellcentre.offset = c(x = gt[1] + 0.5 * cellsize[1], y = gt[4] - (d[2] - 0.5) * abs(cellsize[2]))
     grid = GridTopology(cellcentre.offset, cellsize, cells.dim)
     df = as.vector(Rlogo[,,1])
     for (band in 2:d[3]) df = cbind(df, as.vector(Rlogo[,,band]))
     df = as.data.frame(df)
     names(df) = paste("band", 1:d[3], sep="")
     Rlogo <- SpatialGridDataFrame(grid = grid, data = df)
     summary(Rlogo)
     spplot(Rlogo, zcol=1:3, names.attr=c("red","green","blue"), 
             col.regions=grey(0:100/100),
             main="example of three-layer (RGB) raster image", as.table=TRUE)

