101 lines
3.1 KiB
C
101 lines
3.1 KiB
C
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/*
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Functions that calculate the gravitational potential and its first and second
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derivatives for the rectangular prism in spherical coordinates.
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Uses the formulas in Nagy et al. (2000).
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References
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----------
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* Nagy, D., Papp, G., Benedek, J. (2000): The gravitational potential and its
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derivatives for the prism. Journal of Geodesy, 74, 552–560.
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*/
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#ifndef _TESSEROIDS_GRAV_PRISM_SPH_H_
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#define _TESSEROIDS_GRAV_PRISM_SPH_H_
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/* Needed for definition of PRISM */
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#include "geometry.h"
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/* Transform spherical coordinates to local Cartesian coordinates of the prism
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Parameters:
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* lon, lat, r: spherical coordinates of the point.
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* prism: a prism whose lon, lat, r values will be used as the origin of the
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local coordinate system.
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* x, y, z: used to return the x, y, z Cartesian coordinates of the point.
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*/
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extern int global2local(double lon, double lat, double r, PRISM prism,
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double *x, double *y, double *z);
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/* Rotate the g vector from the prisms coordinate system to the local
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system of the computation point.
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Parameters:
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* atprism: the 3 component gravity vector in the coordinates of the prism.
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* prism: the prism used to calculate atprism.
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* lon, lat, r: coordinates of the computation point.
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* atpoint: used to return the 3 component gravity vector in the coordinates of
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the computation point.
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*/
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extern int g_prism2point(double *atprism, PRISM prism, double lon, double lat,
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double r, double *atpoint);
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/* Rotate the g vector from the prisms coordinate system to the local
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system of the computation point.
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Parameters:
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* atprism: the 9 component gravity tensor in the coordinates of the prism.
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The order is: gxx, gxy, gxz, gyx, gyy, gyz, gzx, gzy, gzz
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* prism: the prism used to calculate atprism.
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* lon, lat, r: coordinates of the computation point.
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* atpoint: used to return the 9 component gravity tensor in the coordinates of
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the computation point.
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*/
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extern int ggt_prism2point(double *atprism, PRISM prism, double lon, double lat,
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double r, double *atpoint);
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/* Calculates the gravity gradient tensor caused by a prism.
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Parameters:
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* prism: the prism whose effect will be calculated.
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* lonp, latp, rp: coordinates of the computation point.
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* ggt: 6 element array used to return the gradient tensor. The order is:
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gxx, gxy, gxz, gyy, gyz, gzz
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*/
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extern int prism_ggt_sph(PRISM prism, double lonp, double latp, double rp,
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double *ggt);
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/* Calculates the gravitational attraction caused by a prism.
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Parameters:
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* prism: the prism whose effect will be calculated.
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* lonp, latp, rp: coordinates of the computation point.
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* gx, gy, gz: used to return the 3 components of the gravity vector
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*/
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extern int prism_g_sph(PRISM prism, double lonp, double latp, double rp,
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double *gx, double *gy, double *gz);
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/* Calculates the potential caused by a prism.
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Parameters:
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* prism: the prism whose effect will be calculated.
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* lonp, latp, rp: coordinates of the computation point.
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Returns:
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* the calculated potential
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*/
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extern double prism_pot_sph(PRISM prism, double lonp, double latp, double rp);
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#endif
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