modiscloud (version 0.14)

run_swath2grid: Run MRTSwath swath2grid tool

Description

MRTSwath is the "MODIS Reprojection Tool for swath products". See: https://lpdaac.usgs.gov/tools/modis_reprojection_tool_swath).

Usage

run_swath2grid(mrtpath = "swath2grid", prmfn = "tmpMRTparams.prm", tifsdir, modfn, geoloc_fn, ul_lon, ul_lat, lr_lon, lr_lat)

Arguments

mrtpath

This is the path to the MRTSwath executable swath2grid. If your ~/.Rprofile file has the location of swath2grid in the PATH, then you can just use mrtpath="swath2grid". Otherwise, the user must provide the full path to swath2grid.

prmfn

The name of the parameter/control file which will be the input to MRTSwath's swath2grid function.

tifsdir

The directory to save the output TIF files in

modfn

The filename of the MODIS data

geoloc_fn

The filename of the corresponding geolocation file (annoyingly, this is a much larger file than the data file!)

ul_lon

Upper left (ul) longitude (x-coordinate) for subsetting

ul_lat

Upper left (ul) latitude (y-coordinate) for subsetting

lr_lon

Lower right (lr) longitude (x-coordinate) for subsetting

lr_lat

Lower right (lr) latitude (y-coordinate) for subsetting

Value

cmdstr The string giving the system command that ran swath2grid

Details

If you want this function to use MRTSwath tool successfully, you should add the directory with the MRTSwath executable to the default R PATH by editing ~/.Rprofile.

References

NASA (2001). "MODLAND Product Filename Convention." .

See Also

write_MRTSwath_param_file

http://landweb.nascom.nasa.gov/cgi-bin/QA_WWW/newPage.cgi?fileName=hdf_filename

Examples

#######################################################
# Run MRTSwath tool "swath2grid"
#######################################################

# Source MODIS files (both data and geolocation)
# Code excluded from CRAN check because it depends on modiscdata
## Not run: 
# library(devtools)
# # The modiscdata (MODIS c=cloud data=data) package is too big for CRAN (60 MB); so it is available on github:
# # https://github.com/nmatzke/modiscdata
# # If we can't get install_github() to work, try install_url():
# # install_github(repo="modiscdata", username="nnmatzke")
# install_url(url="https://github.com/nmatzke/modiscdata/archive/master.zip")
# library(modiscdata)
# moddir = system.file("extdata/2002raw/", package="modiscdata")
# 
# # Get the matching data/geolocation file pairs
# fns_df = check_for_matching_geolocation_files(moddir, modtxt="MYD35_L2", geoloctxt="MYD03")
# fns_df
# 
# # Resulting TIF files go in this directory
# tifsdir = getwd()
# 
# 
# # Box to subset
# ul_lat = 13
# ul_lon = -87
# lr_lat = 8
# lr_lon = -82
# 
# for (i in 1:nrow(fns_df))
# 	{
# 
# 	prmfn = write_MRTSwath_param_file(prmfn="tmpMRTparams.prm", tifsdir=tifsdir, modfn=fns_df$mod35_L2_fns[i], geoloc_fn=fns_df$mod03_fns[i], ul_lon=ul_lon, ul_lat=ul_lat, lr_lon=lr_lon, lr_lat=lr_lat)
# 	print(scan(file=prmfn, what="character", sep="\n"))
# 
# 	run_swath2grid(mrtpath="swath2grid", prmfn="tmpMRTparams.prm", tifsdir=tifsdir, modfn=fns_df$mod35_L2_fns[i], geoloc_fn=fns_df$mod03_fns[i], ul_lon=ul_lon, ul_lat=ul_lat, lr_lon=lr_lon, lr_lat=lr_lat)
# 
# 	}
# 
# list.files(tifsdir, pattern=".tif", full.names=TRUE)
# ## End(Not run)