w3fb12.f File Reference

Lambert(i,j) to lat/lon for grib. More...

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Functions/Subroutines
subroutine	w3fb12 (xi, xj, alat1, elon1, dx, elonv, alatan, alat, elon, ierr)
	Converts the coordinates of a location on Earth given in a grid coordinate system overlaid on a lambert conformal tangent cone projection true at a given N or S latitude to the natural coordinate system of latitude/longitude w3fb12() is the reverse of w3fb11().

Detailed Description

Lambert(i,j) to lat/lon for grib.

Author

John Stackpole

Date

1988-11-25

Definition in file w3fb12.f.

Function/Subroutine Documentation

w3fb12()

subroutine w3fb12	(		xi,
			xj,
			alat1,
			elon1,
			dx,
			elonv,
			alatan,
			alat,
			elon,
			ierr
	)

Converts the coordinates of a location on Earth given in a grid coordinate system overlaid on a lambert conformal tangent cone projection true at a given N or S latitude to the natural coordinate system of latitude/longitude w3fb12() is the reverse of w3fb11().

Uses grib specification of the location of the grid

PROGRAM HISTORY LOG:

• John Stackpole 1988-11-25
• Ralph Jones 1990-04-12 Convert to cft77 fortran.
• Ralph Jones 1994-04-28 Add save statement.

Parameters

[in]	XI	I coordinate of the point real*4
[in]	XJ	J coordinate of the point real*4
[in]	ALAT1	Latitude of lower left point of grid (point 1,1) latitude <0 for southern hemisphere; real*4
[in]	ELON1	Longitude of lower left point of grid (point 1,1) east longitude used throughout; real*4
[in]	DX	Mesh length of grid in meters at tangent latitude
[in]	ELONV	The orientation of the grid. i.e., the east longitude value of the vertical meridian which is parallel to the y-axis (or columns of the grid) along which latitude increases as the y-coordinate increases. real*4 this is also the meridian (on the other side of the tangent cone) along which the cut is made to lay the cone flat.
[in]	ALATAN	The latitude at which the lambert cone is tangent to (touches or osculates) the spherical Earth. set negative to indicate a southern hemisphere projection; real*4
[out]	ALAT	Latitude in degrees (negative in southern hemi.)
[out]	ELON	East longitude in degrees, real*4
[out]	IERR	.eq. 0 if no problem .ge. 1 if the requested xi,xj point is in the forbidden zone, i.e. off the lambert map in the open space where the cone is cut. if ierr.ge.1 then alat=999. and elon=999.

Note

Formulae and notation loosely based on hoke, hayes, and renninger's "map projections and grid systems...", march 1981 afgwc/tn-79/003

Author

John Stackpole

Date

1988-11-25

Definition at line 51 of file w3fb12.f.