[R-sig-Geo] creating STFDF or ST objects in R

[joke atuge]

Hello,
 I am having serious issues creating a space time object with a list of spatialpolygonsdataframes and their dates/ time. I keep getting an error about the time not changing. How can I get this done please? Here's a sample of my data:

[[1]]
class       : SpatialPolygonsDataFrame 
features    : 128 
extent      : -127.44, -67.8964, 1.000039, 31.71804  (xmin, xmax, ymin,  ymax)
coord. ref. : +proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0 
variables   : 1
names       : DDD.LFRP 
min values  :     16.6 
max values  :    488.5 

[[2]]
class       : SpatialPolygonsDataFrame 
features    : 126 
extent      : -129.04, -67.8964, 3.759985, 31.71804  (xmin, xmax, ymin,  ymax)
coord. ref. : +proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0 
variables   : 1
names       : DDD.LFRP 
min values  :       14 
max values  :    335.2
The Time variables look like this:
Timex
 [1] "2008-12-01 04:00:00 GMT" "2008-12-01 06:30:00 GMT"

I have a list of 3,000 and the aim is to structure these spatialpolygons 
dataframe in such a way that I can have monthly aggregates.
 How do I create an STFDF or STIDF, please? I can convert to rasters and agregate but they are of varying extents and resolutions for each time.
Kind regards,
Ajoke

	[[alternative HTML version deleted]]