getDistaz: Retrieve great circle distance information from EarthScope

In IRISSeismic: Classes and Methods for Seismic Data Analysis

Retrieve great circle distance information from EarthScope

Description

The getDistaz method obtains great circle distance data from the EarthScope distaz web service.

Usage

getDistaz(obj, latitude, longitude, staLatitude, staLongitude)

Arguments

obj	an IrisClient object
latitude	latitude of seismic event
longitude	longitude of seismic event
staLatitude	latitude of seismic station
staLongitude	longitude of seismic station

Details

The distance-azimuth service will calculate the great-circle angular distance, azimuth, and back azimuth between two geographic coordinate pairs. Azimuth and back azimuth are measured clockwise from North.

Value

A dataframe with the following columns:

ellipsoid.semiMajorAxis, ellipsoid.flattening, ellipsoid.name, fromlat, fromlon, tolat, tolon,
  azimuth,backAzimuth, distance, distanceMeters

Where fromlat is the event latitude, fromlon is the event longitude, tolat is the station latitude, and tolon is the station longitude. azimuth, backAzimuth, and distance are measured in degrees. distanceMeters is distance in meters. ellipsoid.semiMajorAxis, ellipsoid.flattening, and ellipsoid.name refer to the World Geodetic System standard coordinate system version used to correct for ellipticity when converting to geocentric latitudes.

Only a single row is returned.

Author(s)

Jonathan Callahan [e-mail]

References

The EarthScope distaz webservice:

https://service.earthscope.org/irisws/distaz/1/

See Also

IrisClient-class

IRISSeismic documentation built on June 8, 2025, 10:30 a.m.