Example half degree grid data : people per cell estimates for 2000 from IIASA (International Institute for Applied System Analysis) (sp, SpatialGridDataFrame).
The format is:
Formal class 'SpatialGridDataFrame'
[package "sp"] with 6 slots ..@ data :'data.frame': 259200 obs. of 1
variable: .. ..$ pa2000.asc: num [1:259200] NA NA NA NA NA NA NA NA NA NA
... ..@ grid :Formal class 'GridTopology' [package "sp"] with 3 slots .. ..
..@ cellcentre.offset: num [1:2] -179.8 -89.8 .. .. ..@ cellsize : num [1:2]
0.5 0.5 .. .. ..@ cells.dim : int [1:2] 720 360 ..@ grid.index : int(0) ..@
coords : num [1:2, 1:2] -179.8 179.8 -89.8 89.8 .. ..- attr(*,
"dimnames")=List of 2 .. .. ..$ : NULL .. .. ..$ : chr [1:2] "coords.x1"
"coords.x2" ..@ bbox : num [1:2, 1:2] -180 -90 180 90 .. ..- attr(*,
"dimnames")=List of 2 .. .. ..$ : chr [1:2] "coords.x1" "coords.x2" .. ..
..$ : chr [1:2] "min" "max" ..@ proj4string:Formal class 'CRS' [package
"sp"] with 1 slots .. .. ..@ projargs: chr " +proj=longlat +datum=WGS84
+ellps=WGS84 +towgs84=0,0,0" From International Institute for Applied System Analysis (IIASA) GGI Scenario Database, 2007 Available at: http://www.iiasa.ac.at/Research/GGI/DB/ The data are made available for individual, academic research purposes only and on a "as is" basis, subject to revisions without further notice. Commercial applications are not permitted.
The data is used as the default dataset in other functions, e.g. mapGriddedData(), when no data file is given.
Grubler, A., O'Neill, B., Riahi, K., Chirkov, V., Goujon, A., Kolp, P., Prommer, I., Scherbov, S. & Slentoe, E. (2006) Regional, national and spatially explicit scenarios of demographic and economic change based on SRES. Technological Forecasting and Social Change doi:10.1016/j.techfore.2006.05.023