norm_chisq {tectonicr} | R Documentation |
Normalized Chi-Squared Test for Circular Data
Description
A quantitative comparison between the predicted and observed directions of
is obtained by the calculation of the average
azimuth and by a normalized
test.
Usage
norm_chisq(obs, prd, unc)
Arguments
obs |
Numeric vector containing the observed azimuth of
|
prd |
Numeric vector containing the modeled azimuths of
|
unc |
Uncertainty of observed |
Details
The normalized test is
The value of the chi-squared test statistic is a number between 0 and 1
indicating the quality of the predicted
directions. Low values
(
) indicate good agreement,
high values (
) indicate a systematic misfit between predicted and
observed
directions.
Value
Numeric vector
References
Wdowinski, S., 1998, A theory of intraplate tectonics. Journal of Geophysical Research: Solid Earth, 103, 5037-5059, doi: 10.1029/97JB03390.
Examples
data("nuvel1")
PoR <- subset(nuvel1, nuvel1$plate.rot == "na") # North America relative to
# Pacific plate
data(san_andreas)
point <- data.frame(lat = 45, lon = 20)
prd <- model_shmax(point, PoR)
norm_chisq(obs = c(50, 40, 42), prd$sc, unc = c(10, NA, 5))
data(san_andreas)
prd2 <- PoR_shmax(san_andreas, PoR, type = "right")
norm_chisq(obs = prd2$azi.PoR, 135, unc = san_andreas$unc)