Proj.md

User Function Proj

General Information

• USF Fortran File: USF_proj.F90

• USF Name: xy2Lon xy2Lat LonLat2x LonLat2y

• Required Input Variable(s): x,y or Lon,Lat provided as USF arguments

General Description

USF_proj.F90 contains generic user functions to compute longitude and latitude from projected x,y coordinates and conversely. It relies on generic utilities in the module file projUtils.

SIF contents

The required keywords in the SIF file for this user function are:

e.g. to compute longitude and latitude in the initial conditions using nodal coordinates or conversely

Initial Condition 1
  longitude = Variable Coordinate 1, Coordinate 2
    Real procedure "ElmerIceUSF" "xy2Lon"

  latitude = Variable Coordinate 1, Coordinate 2
    Real procedure "ElmerIceUSF" "xy2Lat"

  x = Variable longitude, latitude
    Real procedure "ElmerIceUSF" "LonLat2x"

  y = Variable longitude, latitude
    Real procedure "ElmerIceUSF" "LonLat2y"
End

The definition of the projected coordinate system must be given in the Simulation section:

Simulation 

! Antarctic Polar Stereographic EPSG:3031
  projection type = String "polar stereographic south"
  central_meridian = Real 0.0
  latitude_of_origin = Real -71.0

! NSIDC Sea Ice Polar Stereographic North EPSG:3014
  projection type = String "polar stereographic north"
  central_meridian = Real -45.0
  latitude_of_origin = Real 70.0

End

Tests and Examples

Functionality tested in [ELMER_TRUNK]/elmerice/Tests/Proj_South: compute Lon/Lat and back x,y