; docformat = 'rst'
;
; NAME:
;    GENOIDE_XMLOPEN
; PURPOSE:
;    Open a file, print a VOTable header for Genoide, and return the file unit
;+
; :Description:
;    Open a file, print a VOTable header for Genoide, and return the file unit
;
;    The suite of small routines GENOIDE_XML... allow to open, complete, close, read
;    an XML file in the Genoid standards. 
;
; :Categories:
;    Disk I/O, Genoide
;    
; :Params:
;    FILE: in, required, type=string
;        The path to the file to be opened
;    nRow: in, optional, type=integer
;        Number of epochs to be subsequently added to the file
;
; :Returns: The file unit to be subsequently use to fill the file.
;
; :Author:
;    B.Carry (IMCCE)
;
; :History:
;     Change History::
;        Written in July 2013, B. Carry (IMCCE)
;        2013 Sep. - B.Carry (IMCCE) - Allow unknown number of rowk
;-
function genoide_xmlOpen, FILE, nRow

 ;--I-- Open the File for Writing
  openw, unit, file, /GET_LUN

 ;--II-- XML Header
  printf, unit, '<?xml version="1.0" encoding="UTF-8"?>'
  printf, unit, '<vot:VOTABLE version="1.2" xsi:schemaLocation="http://www.ivoa.net/xml/VOTable/v1.2 http://www.ivoa.net/xml/VOTable/VOTable-1.2.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:vot="http://www.ivoa.net/xml/VOTable/v1.2" xmlns:stc="http://www.ivoa.net/xml/STC">'
  printf, unit, '  <vot:INFO ID="status" name="QUERY_STATUS" value="OK"/>'
  printf, unit, '  <vot:RESOURCE>'

 ;--III-- Number of Row
  if keyword_set(NROW) then printf, unit, '    <vot:TABLE name="obs.dat" nrows="'+strtrim(string(nRow,format='(I)'),2)+'">' $
                       else printf, unit, '    <vot:TABLE name="obs.dat" nrows="<NROW>">'

 ;--IV-- Significance of Columns
  printf, unit, '      <vot:FIELD name="tjj" datatype="double"/>'
  printf, unit, '      <vot:FIELD name="tiso" datatype="char"/>'
  printf, unit, '      <vot:FIELD name="ref_name" datatype="char"/>'
  printf, unit, '      <vot:FIELD name="ref_system" datatype="char"/>'
  printf, unit, '      <vot:FIELD name="xobs" datatype="float" unit="arcsec"/>'
  printf, unit, '      <vot:FIELD name="yobs" datatype="float" unit="arcsec"/>'
  printf, unit, '      <vot:FIELD name="xobs_err" datatype="float" unit="arcsec"/>'
  printf, unit, '      <vot:FIELD name="yobs_err" datatype="float" unit="arcsec"/>'
  printf, unit, '      <vot:FIELD name="xcalc" datatype="float" unit="arcsec"/>'
  printf, unit, '      <vot:FIELD name="ycalc" datatype="float" unit="arcsec"/>'
  printf, unit, '      <vot:FIELD name="xomc" datatype="float" unit="arcsec"/>'
  printf, unit, '      <vot:FIELD name="yomc" datatype="float" unit="arcsec"/>'
  printf, unit, '      <vot:FIELD name="timescale" datatype="char"/>'
  printf, unit, '      <vot:FIELD name="centerframe" datatype="float"/>'
  printf, unit, '      <vot:FIELD name="typeframe" datatype="float"/>'
  printf, unit, '      <vot:FIELD name="coordtype" datatype="float"/>'
  printf, unit, '      <vot:FIELD name="refframe" datatype="float"/>'
  printf, unit, '      <vot:FIELD name="obsuai" datatype="char"/>'
  printf, unit, '      <vot:FIELD name="bibitem" datatype="char"/>'
  printf, unit, '      <vot:DATA>'
  printf, unit, '        <vot:TABLEDATA>'

 ;--V-- Return the File Unit (for File Completion)
  return, unit

end