getElev: Elevation

In leppott/CASTfxn: Functions for Causal Assessment Screening Tool (CAST)

Description

Get location elevation.

Usage

getElev(df_loc, Lat, Long, elev_units = "meters",
  proj_loc = "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs")

Arguments

df_loc	Data frame with location information
Lat	df_loc column name; Latitude (decimal degrees). Default = Latitude
Long	df_loc column name; Longitude (decimal degrees). Default = Longitude
elev_units	Requested elevation units; meters or feet. Default = meters.
proj_loc	Projection. Default is WGS84.

Details

Uses the elevatr package to acccess USGS Elevation Point Query Service (EPQS).

The EPQS is based on the National Map. The vertical accuracy is 3.04 meters.

https://www.usgs.gov/faqs/what-vertical-accuracy-seamless-3dep-dems

getElev assumes WGS84 but any projections can be entered.

Requires package elevatr and sp.

Requires a data frame with latitude and longitude. Other arguments are desired units and a projection.

The output is the input data frame with the elevation and units columns appended to it.

Value

A data frame with elevation and units columns appended to it.

Examples

#Function Arguments
df_loc <- head(data_Sites)
Lat <- "FinalLatitude"
Long <- "FinalLongitude"
elev_units <- "feet"
proj_loc <- "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"

# Run Function
df_elev <- getElev(df_loc, Lat, Long, elev_units, proj_loc)

/dontrun{
# Save Results
write.table(df_elev, "Elev.tsv", sep="\t", row.names=FALSE, col.names = TRUE)
}

leppott/CASTfxn documentation built on Sept. 6, 2019, 11:04 p.m.