Import BIL files in R, without the hdr file
I think BANDROWBYTES and TOTALROWBYTES should both be 214 (107 * 2)
which is the number of columns times the 2 bytes for 16 NBITS.
You can infer what should happen from another example, which you can
do by something like this:
f <- system.file("pictures/erdas_spnad83.tif", package = "rgdal")[1]
g <- readGDAL(f)
## write out to EHdr format and read in the text
writeGDAL(g, "a.bil", "EHdr")
readLines("a.hdr")
Otherwise, refer to the GDAL page for this driver:
http://www.gdal.org/frmt_various.html#EHdr
Cheers, Mike.
On Wed, Mar 28, 2012 at 12:47 AM, Guillermo Olmedo
<folmedo at mendoza.inta.gov.ar> wrote:
Hi list!
I'm trying to import a BIL binary file into R. I've obtained the file
running a soft called TIMESAT[1] but i only have the BIL file, not the HDR.
Because i know how timesat generates the files I've the number of cols ands
rows. Also i know the file its a 16 bit signed integer and little endian.
I've followed the procedure here [2] and the info i know from the file to
write my own hdr. But still doesnt work. Without the hdr file i still can
import the bil file into ERDAS using import binary and it works flawlessly,
but i don't want to use ERDAS.
This is my hdr file:
BYTEORDER ? ? ?I
LAYOUT ? ? ? ? BIL
NROWS ? ? ? ? ?79
NCOLS ? ? ? ? ?107
NBANDS ? ? ? ? 1
NBITS ? ? ? ? ?16
BANDROWBYTES ? 80
TOTALROWBYTES ?80
PIXELTYPE ? ? ?INTEGER
ULXMAP ? ? ? ? 0
ULYMAP ? ? ? ? 0
XDIM ? ? ? ? ? 107
YDIM ? ? ? ? ? 79
Maybe Bandrowbytes and totalrowbytes are wrong. At this moment the spatial
location doesnt matters so i left ulxmap and ulymap as 0.
My code is:
BIL <- raster("amplitud.bil", native=T)
dataType(bio) <- 'INT2S'
plot(BIL)
And the same result with:
BIL <- raster(ncols=107, nrows= 79)
BIN <- readBin("amplitud.bil", what="integer", n=8453, endian="little",
signed=TRUE, size=2)
BIL <- setValues(BIL, BIN)
plot(BIL)
With the img generated in ERDAS i can compare with the R result and clearly
its not working good.
Also, here you can have a copy of my files:
http://ubuntuone.com/116tXWeA7rrwOc9SWsp6Wl (63kb)
Anyone have a better recipe?
Thanks in advance, regards!
[1] http://www.nateko.lu.se/TIMESAT/timesat.asp
[2] http://r.789695.n4.nabble.com/importing-bil-files-td1677546.html
--
Ing. Agr. Guillermo Federico OLMEDO
Laboratorio de Geom?tica
?rea de Recursos Naturales
EEA INTA Mendoza
Oficina: San Mart?n 3853. Mayor. Drummond.
Luj?n de Cuyo. Mendoza.
ARGENTINA (M5507EVY)
Tel: +54 (261) 496 3020 int. 252 / Cel. 261 6779074
http://www.inta.gov.ar/mendoza/invest/Gr_RecursosNaturales.htm
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Michael Sumner Institute for Marine and Antarctic Studies, University of Tasmania Hobart, Australia e-mail: mdsumner at gmail.com