DESCRIPTION

r.in.usgs downloads and patches selected USGS datasets (NED, NLCD, NAIP) to the current GRASS computational region and coordinate reference system. Associated parameters are automatically passed to The National Map Access API, downloaded to a user-specified local directory, then imported and patched. r.in.usgs supports the following datasets:

NOTES

NED data are available at resolutions of 1 arc-second (about 30 meters), 1/3 arc-second (about 10 meters), and in limited areas at 1/9 arc-second (about 3 meters).

NLCD data are available for years 2001, 2006, and 2011 (see nlcd_dataset option) at 30m resolution and include Land Cover, Percent Developed Imperviousness, and Percent Tree Canopy (see nlcd_subset option).

NAIP is available at 1 m resolution.

If the i flag is set, only information about data meeting the input parameters is displayed without downloading the data.

By default, downloaded files are kept in the specified output_direcory, so that they can be reused in case different computational region is required. However, unzipped files and imported rasters before patching are removed. If the k flag is set, extracted files from compressed archives are also kept within the download directory after the import.

By default, resampling method is chosen based on the nature of the dataset, bilinear for NED and nearest for NLCD and NAIP. This can be changed with option resampling_method.

EXAMPLE

We will download NED 1/9 arc-second digital elevation model in the extent of raster 'elevation'. First, we just list the files to be downloaded (change output directory depending on the operating system): 
g.region raster=elevation
r.in.usgs product=ned ned_dataset=ned19sec output_directory=/tmp output_name=ned -i

USGS file(s) to download:
-------------------------
Total download size:	826.95 MB
Tile count:	4
USGS SRS:	wgs84
USGS tile titles:
USGS NED ned19_n35x75_w078x75_nc_statewide_2003 1/9 arc-second 2012 15 x 15 minute IMG
USGS NED ned19_n36x00_w078x75_nc_statewide_2003 1/9 arc-second 2012 15 x 15 minute IMG
USGS NED ned19_n35x75_w079x00_nc_statewide_2003 1/9 arc-second 2012 15 x 15 minute IMG
USGS NED ned19_n36x00_w079x00_nc_statewide_2003 1/9 arc-second 2012 15 x 15 minute IMG
-------------------------
To download USGS data, remove i flag, and rerun r.in.usgs.
We proceed with the download: 
r.in.usgs product=ned ned_dataset=ned19sec output_directory=/tmp output_name=ned
r.colors map=ned_small color=grey
We change the computational region to a smaller extent and create a new DEM, downloaded files will be used. 
g.region n=224649 s=222000 w=633000 e=636000
r.in.usgs product=ned ned_dataset=ned19sec output_directory=/tmp output_name=ned_small
For a different extent we download NAIP imagery: 
g.region n=224649 s=222000 w=636000 e=639000
r.in.usgs product=naip output_directory=/tmp output_name=ortho
For a different extent we download NLCD land cover: 
g.region n=224649 s=222000 w=639000 e=642000
r.in.usgs product=nlcd nlcd_dataset=nlcd2011 nlcd_subset=landcover output_directory=/tmp output_name=nlcd
NED and ortho
Figure: Downloaded NED (large and small extent), NAIP orthoimagery, and NLCD land cover

REFERENCES

TNM Access API Guide
National Elevation Dataset
National Land Cover Dataset

SEE ALSO

g.region, r.import, r.patch, r.colors

AUTHOR

Zechariah Krautwurst, 2017 MGIST Candidate, North Carolina State University
Anna Petrasova, NCSU GeoForAll Lab
(Google Summer of Code 2017, mentors: Anna Petrasova, Vaclav Petras)