https://github.com/cran/gstat
Tip revision: 0957ff04666ab93ef9952a365a048910b8daf50b authored by Edzer Pebesma on 05 September 2024, 09:50:02 UTC
version 2.1-2
version 2.1-2
Tip revision: 0957ff0
vario_io.h
double sem_cov_ab(VARIOGRAM *v, DPOINT *a, DPOINT *b, int sem);
/* covariance: */
#define COVARIANCE(v,a,b) ((IS_POINT(a) && IS_POINT(b) && !gl_longlat) ? \
(get_covariance(v,a->x - b->x,a->y - b->y, a->z - b->z)) : \
sem_cov_ab(v,a,b,0))
/* generalized covariance: */
#define GCV(v,a,b) ((IS_POINT(a) && IS_POINT(b) && !gl_longlat) ? \
(v->max_val - get_semivariance(v,a->x - b->x,a->y - b->y, a->z - b->z)) : \
(v->max_val - sem_cov_ab(v,a,b,1)))
/*
* CME is the measurement error-adjustment to GCV or COVARIANCE:
* see Cressie, Statistics for Spatial Data, revised ed. 1993,
* eq. 3.2.25-3.2.27, and page 379
*/
#define CME(v,a,b,dist) ((IS_POINT(a) && IS_POINT(b) && \
(a == b || dist(a, b) == 0.0)) ? v->measurement_error : 0.0)
#define GCV0(v,a,b,dist) (GCV(v,a,b) - CME(v,a,b,dist))
#define COVARIANCE0(v,a,b,dist) (COVARIANCE(v,a,b) - CME(v,a,b,dist))