Rlogo jpeg image — Rlogo • sp

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

data(Rlogo)

Format

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

Examples

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)
#> Object of class SpatialGridDataFrame
#> Coordinates:
#>   min max
#> x   0 101
#> y -77   0
#> Is projected: NA 
#> proj4string : [NA]
#> Grid attributes:
#>   cellcentre.offset cellsize cells.dim
#> x               0.5        1       101
#> y             -76.5        1        77
#> Data attributes:
#>      band1           band2           band3      
#>  Min.   :  0.0   Min.   :  0.0   Min.   :  0.0  
#>  1st Qu.:131.0   1st Qu.:138.0   1st Qu.:151.0  
#>  Median :196.0   Median :199.0   Median :215.0  
#>  Mean   :182.3   Mean   :185.4   Mean   :192.8  
#>  3rd Qu.:254.0   3rd Qu.:255.0   3rd Qu.:254.0  
#>  Max.   :255.0   Max.   :255.0   Max.   :255.0  
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)