HydroData: HydroData

Description Usage Arguments Author(s) Examples

The United States Geological Survey maintains a hierarchical system of hydrologic units each assigned a unique code (HUC). The hierarchical level is described by the number of digits in the code. A two-digit code (eg. HUC 2) is the coarsest unit of aggregation while the HUC 12 is the finest resolution. The spatial geometries of these units are stored in the Watershed Boundary Dataset with coverage of the United States. findWBD returns a SpatialPolygonsDataFrame* of WBD boundaries for the specified level within an AOI. Pending the query, data comes from the USGS CIDA server or the USGS staged products FTP.

Below you can see the general factors for each HUC level:\

Name	Digits	Average Size (sqmiles)	Example Name	Example Code
Region	2	177,560	Pacific Northwest	17
Subregion	4	16,800	Lower Snake	1706
Basin	6	10,596	Lower Snake	170601
Subbasin	8	700	Imnaha River	17060102
Watershed	10	227	Upper Imnaha River	1706010201
Subwatershed	12	40	North Fork Imnaha River	170601020101

1 2	findWBD(AOI, level = 8, subbasins = FALSE, crop = TRUE, ids = FALSE)

`AOI`	A Spatial* or simple features geometry, can be piped from getAOI
`level`	defines the HUC level of interest (default = 8)
`subbasins`	If TRUE, all subbasins of the supplied level will be joined to retuned list
`crop`	If TRUE, all objects are cropped to the AOI boundaries (default = `TRUE`)
`ids`	If TRUE, a vector of finest resolution HUC codes is added to returned list (default = `FALSE`)

Mike Johnson

## Not run: 
# Get Cropped HUC8s for AOI
 getAOI(list("UCSB", 10, 10)) %>% findWBD()

# Get Cropped HUC10s for AOI
 getAOI(list("UCSB", 10, 10)) %>% findWBD(level = 10)

# Get Cropped HUC8s, HUC10s and HUC12s for AOI
 getAOI(clip = list("UCSB", 10, 10)) %>% findWBD(level = 8, subbasins = TRUE)

# Get uncropped HUC10s for AOI
 getAOI(clip = list("UCSB", 10, 10)) %>% findWBD(level = 10, crop = FALSE)

## End(Not run)