Generates a global grid (map) of the 13th Generation International Geomagnetic Reference Field (IGRF) for a predefined spatial resolution (in decimal degrees).
igrf_grid(field = "main", year, type = "spheroid", altitude, resolution = 5)Arguments
- field
main field (default = "main") or secular variation ("variation") data output
- year
year A.D. Must be greater than or equal to 1900.0 and less than or equal to 2030. Warning message is given for dates greater than 2025.
- type
"spheroid" (default) or "sphere" representation
- altitude
in km above the earth surface for a geodetic type, or distance from the earth center for the spherical representation.
- resolution
spatial resolution of the output map in decimal degree (default = 5).
Value
a data frame with components X,Y,Z,F, D, H and I for the main geomagnetic field or the delta (dX etc) variants for the secular variation on a regular grid. Data is returned in a tidy format with required latitude and longitude columns for convenient plotting.
Examples
grid <- igrf::igrf_grid(
year = 2000,
field = "main",
type = "spheroid",
altitude = 2,
resolution = 5
)