findNHD returns a SpatialLinesDataframe of all NHDFlowlines reaches within an AOI.
Data comes from the USGS CIDA server and contain 92 attributes, perhaps most notably:
'comid' : integer Integer value that uniquely identifies the occurrence of each feature in the NHD
'reachcode' : character Unique identifier for a ‘reach’. The first eight numbers are the WBD_HUC8
'fdate': POSITct Date of last feature modification
'gnis_id' : character Unique identifier assigned by GNIS
'gnis_name' : character Proper name, term, or expression by which a particular geographic entity is known
'lengthkm' : numeric Length of linear feature based on Albers Equal Area
'areasqkm' : numeric Area of areal feature based on Albers Equal Area,
'flowdir' : character Direction of flow relative to coordinate order.
'wbareacomi' : integer The COMID of the waterbody through which the flowline flows.
'ftype': character unique identifier of a feature type
findNHD(AOI = NULL, ids = FALSE)
| AOI | A Spatial* or simple features geometry, can be piped from getAOI |
|---|---|
| ids | If TRUE, a vector of NHD COMIDs is added to retuned list (default = |
a list() of minimum length 2: AOI and nhd
# NOT RUN { nhd = getAOI(clip = list("Tuscaloosa, AL", 10, 10)) %>% findNHD() # }