Run MRTSwath swath2grid tool

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Description

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

Usage

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run_swath2grid_mod09nrt(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

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.

Value

cmdstr The string giving the system command that ran swath2grid

Author(s)

Nicholas J. Matzke matzke@berkeley.edu

See Also

write_MRTSwath_param_file_mod09nrt

http://landweb.nascom.nasa.gov/cgi-bin/QA_WWW/newPage.cgi?fileName=hdf_filename @cite NASA2001

Examples

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#######################################################
# 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)
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="MOD09", geoloctxt="MOD03")
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_mod09nrt(prmfn="tmpMRTparams.prm", tifsdir=tifsdir,
 modfn=fns_df$mod09_fns[i], geoloc_fn=fns_df$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_mod09nrt(mrtpath="swath2grid", prmfn="tmpMRTparams.prm", tifsdir=tifsdir,
 modfn=fns_df$mod309_fns[i], geoloc_fn=fns_df$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)