[R-sig-Geo] convert a shapefile to geotiff with type = "Float32"

[Hailey Eckstrand]

Hello List,
I am trying to load in a shapefile and then write it out as a geoTiff.
I am using the package rgdal.

library("rgdal")
## load in my shapefile
shp <- readOGR("/home/data3/projects/hydrology/vic/output/water_balance/peace_cc/summary",
"peace_base_et_6190")

# Just to be clear, here is the structure of my data
str(shp)
Formal class 'SpatialPointsDataFrame' [package "sp"] with 5 slots
  ..@ data       :'data.frame': 3975 obs. of  13 variables:
  .. ..$ jan: num [1:3975] 12 12.4 12.3 12.3 12.5 ...
  .. ..$ feb: num [1:3975] 12.8 13.2 13 13.1 13.5 ...
  .. ..$ mar: num [1:3975] 16.3 16.6 16.8 16.8 17.1 ...
  .. ..$ apr: num [1:3975] 31.2 33.7 30.1 28.1 29.2 ...
  .. ..$ may: num [1:3975] 106 111 101 99 103 ...
  .. ..$ jun: num [1:3975] 99.4 116 121.1 115.1 108 ...
  .. ..$ jul: num [1:3975] 57.8 56.9 74.7 69.5 65 ...
  .. ..$ aug: num [1:3975] 53.8 51.2 59.5 58.6 57.3 ...
  .. ..$ sep: num [1:3975] 44 40.6 52.8 49.4 49.2 ...
  .. ..$ oct: num [1:3975] 32.4 32 35.3 34.1 34.9 ...
  .. ..$ nov: num [1:3975] 12.6 12.9 12.9 12.9 13.4 ...
  .. ..$ dec: num [1:3975] 12.8 13.2 13.2 13.1 13.6 ...
  .. ..$ sum: num [1:3975] 491 510 542 522 517 ...
  ..@ coords.nrs : num(0)
  ..@ coords     : num [1:3975, 1:2] -123 -123 -122 -123 -123 ...
  .. ..- attr(*, "dimnames")=List of 2
  .. .. ..$ : NULL
  .. .. ..$ : chr [1:2] "coords.x1" "coords.x2"
  ..@ bbox       : num [1:2, 1:2] -127.7 54.2 -120.6 58
  .. ..- 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 +ellps=WGS84 +datum=WGS84
+no_defs +towgs84=0,0,0"

# Convert it to a SpatialGridDataGrame, so I can writeGDAL
gridded(shp) <- TRUE
shp.grid <- as(shp, "SpatialGridDataFrame")

# structure of my SpatialGridDataFrame
str(shp.grid)
Formal class 'SpatialGridDataFrame' [package "sp"] with 6 slots
  ..@ data       :'data.frame': 7130 obs. of  13 variables:
  .. ..$ jan: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ feb: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ mar: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ apr: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ may: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ jun: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ jul: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ aug: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ sep: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ oct: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ nov: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ dec: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ sum: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
  ..@ grid       :Formal class 'GridTopology' [package "sp"] with 3 slots
  .. .. ..@ cellcentre.offset: Named num [1:2] -127.7 54.2
  .. .. .. ..- attr(*, "names")= chr [1:2] "coords.x1" "coords.x2"
  .. .. ..@ cellsize         : Named num [1:2] 0.0625 0.0625
  .. .. .. ..- attr(*, "names")= chr [1:2] "coords.x1" "coords.x2"
  .. .. ..@ cells.dim        : Named int [1:2] 115 62
  .. .. .. ..- attr(*, "names")= chr [1:2] "coords.x1" "coords.x2"
  ..@ grid.index : int(0)
  ..@ coords     : num [1:2, 1:2] -127.7 -120.6 54.2 58
  .. ..- attr(*, "dimnames")=List of 2
  .. .. ..$ : NULL
  .. .. ..$ : chr [1:2] "coords.x1" "coords.x2"
  ..@ bbox       : num [1:2, 1:2] -127.8 54.2 -120.6 58.1
  .. ..- 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 +ellps=WGS84 +datum=WGS84
+no_defs +towgs84=0,0,0"

# attempt to write out a geotiff
writeGDAL(shp.grd, "/home/data2/gis/AT_Hailey/r_rasters/test.tif",
drivername = "GTiff", type = "Float32", mvFlag = NA, options=NULL,
copy_drivername = "GTiff")


The file that I write out only has NA values. I realize something is
wrong as I haven't figured out how to define which column I'd like to
convert.
Thanks in advance,
Hailey