text: #!/home/wilsonsf/environments/my_env/bin/python3
  # ******************************************************************************
  #  $Id$
  #
  #  Project:  GDAL
  #  Purpose:  Convert GCPs to a point layer.
  #  Author:   Frank Warmerdam, warmerdam@pobox.com
  #
  # ******************************************************************************
  #  Copyright (c) 2005, Frank Warmerdam <warmerdam@pobox.com>
  #
  #  Permission is hereby granted, free of charge, to any person obtaining a
  #  copy of this software and associated documentation files (the "Software"),
  #  to deal in the Software without restriction, including without limitation
  #  the rights to use, copy, modify, merge, publish, distribute, sublicense,
  #  and/or sell copies of the Software, and to permit persons to whom the
  #  Software is furnished to do so, subject to the following conditions:
  #
  #  The above copyright notice and this permission notice shall be included
  #  in all copies or substantial portions of the Software.
  #
  #  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  #  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  #  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  #  THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  #  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  #  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  #  DEALINGS IN THE SOFTWARE.
  # ******************************************************************************
  
  import sys
  
  from osgeo import gdal
  from osgeo import ogr
  from osgeo import osr
  
  
  def Usage():
      print('Usage: gcps2vec.py [-of <ogr_drivername>] [-p] <raster_file> <vector_file>')
      sys.exit(1)
  
  # =============================================================================
  # 	Mainline
  # =============================================================================
  
  
  out_format = 'GML'
  in_file = None
  out_file = None
  pixel_out = 0
  
  gdal.AllRegister()
  argv = gdal.GeneralCmdLineProcessor(sys.argv)
  if argv is None:
      sys.exit(0)
  
  # Parse command line arguments.
  i = 1
  while i < len(argv):
      arg = argv[i]
  
      if arg == '-of':
          i = i + 1
          out_format = argv[i]
  
      elif arg == '-p':
          pixel_out = 1
  
      elif in_file is None:
          in_file = argv[i]
  
      elif out_file is None:
          out_file = argv[i]
  
      else:
          Usage()
  
      i = i + 1
  
  if out_file is None:
      Usage()
  
  # ----------------------------------------------------------------------------
  # Open input file, and fetch GCPs.
  # ----------------------------------------------------------------------------
  ds = gdal.Open(in_file)
  if ds is None:
      print('Unable to open %s' % in_file)
      sys.exit(1)
  
  gcp_srs = ds.GetGCPProjection()
  gcps = ds.GetGCPs()
  
  ds = None
  
  if gcps is None or not gcps:
      print('No GCPs on file %s!' % in_file)
      sys.exit(1)
  
  # ----------------------------------------------------------------------------
  # Create output file, and layer.
  # ----------------------------------------------------------------------------
  
  drv = ogr.GetDriverByName(out_format)
  if drv is None:
      print('No driver named %s available.' % out_format)
      sys.exit(1)
  
  ds = drv.CreateDataSource(out_file)
  
  if pixel_out == 0 and gcp_srs != "":
      srs = osr.SpatialReference()
      srs.ImportFromWkt(gcp_srs)
  else:
      srs = None
  
  if pixel_out == 0:
      geom_type = ogr.wkbPoint25D
  else:
      geom_type = ogr.wkbPoint
  
  layer = ds.CreateLayer('gcps', srs, geom_type=geom_type)
  
  if pixel_out == 0:
      fd = ogr.FieldDefn('Pixel', ogr.OFTReal)
      layer.CreateField(fd)
  
      fd = ogr.FieldDefn('Line', ogr.OFTReal)
      layer.CreateField(fd)
  else:
      fd = ogr.FieldDefn('X', ogr.OFTReal)
      layer.CreateField(fd)
  
      fd = ogr.FieldDefn('Y', ogr.OFTReal)
      layer.CreateField(fd)
  
      fd = ogr.FieldDefn('Z', ogr.OFTReal)
      layer.CreateField(fd)
  
  fd = ogr.FieldDefn('Id', ogr.OFTString)
  layer.CreateField(fd)
  
  fd = ogr.FieldDefn('Info', ogr.OFTString)
  layer.CreateField(fd)
  
  # ----------------------------------------------------------------------------
  # Write GCPs.
  # ----------------------------------------------------------------------------
  
  for gcp in gcps:
  
      feat = ogr.Feature(layer.GetLayerDefn())
  
      if pixel_out == 0:
          geom = ogr.Geometry(geom_type)
          feat.SetField('Pixel', gcp.GCPPixel)
          feat.SetField('Line', gcp.GCPLine)
          geom.SetPoint(0, gcp.GCPX, gcp.GCPY, gcp.GCPZ)
      else:
          geom = ogr.Geometry(geom_type)
          feat.SetField('X', gcp.GCPX)
          feat.SetField('Y', gcp.GCPY)
          feat.SetField('Z', gcp.GCPZ)
          geom.SetPoint(0, gcp.GCPPixel, gcp.GCPLine)
  
      feat.SetField('Id', gcp.Id)
      feat.SetField('Info', gcp.Info)
  
      feat.SetGeometryDirectly(geom)
      layer.CreateFeature(feat)
  
  feat = None
  ds.Destroy()
  