NCEPLIBS-w3emc  2.11.0
Functions/Subroutines
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(). More...
 

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]XII coordinate of the point real*4
[in]XJJ coordinate of the point real*4
[in]ALAT1Latitude of lower left point of grid (point 1,1) latitude <0 for southern hemisphere; real*4
[in]ELON1Longitude of lower left point of grid (point 1,1) east longitude used throughout; real*4
[in]DXMesh length of grid in meters at tangent latitude
[in]ELONVThe 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]ALATANThe 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]ALATLatitude in degrees (negative in southern hemi.)
[out]ELONEast 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.