Project Example

[Visual Basic 6.0]
Private Sub Test()
  'Set up spatial references
  Dim pSpatialReferenceEnv As SpatialReferenceEnvironment
  Set pSpatialReferenceEnv = New SpatialReferenceEnvironment
  Dim pFromSR As ISpatialReference
  Set pFromSR = pSpatialReferenceEnv.CreateGeographicCoordinateSystem(esriSRGeoCS_NAD1983)
  Dim pToSR As ISpatialReference
  Set pToSR = pSpatialReferenceEnv.CreateProjectedCoordinateSystem(esriSRProjCS_NAD1983UTM_10N)
  
  'Set up Point for transforming
  Dim pT2D As ITransform2D
  Set pT2D = CreatePoint(-122, 37)
  Dim pPt As IPoint
  Set pPt = pT2D
  Set pPt.SpatialReference = pFromSR
  pPt.Project pToSR
  
  'Set up Comparison Point
  'This is the point the transformation should result in
  Dim pPt2 As IPoint
  Set pPt2 = New Point
  pPt2.PutCoords -121, 42
  Set pPt2.SpatialReference = pFromSR
  pPt2.Project pToSR

  'Transform
  Dim pA2D2 As IAffineTransformation2D2
  Dim pA2D As IAffineTransformation2D
  Dim pOrigin As IPoint

  '  Set up Affine Transformation
  '    MoveOrigin is at the same location as the Point to be transformed: Yields accurate results
  Set pA2D2 = New AffineTransformation2D
  pA2D2.Move 1, 5
  Set pA2D = pA2D2
  Set pOrigin = CreatePoint(-122, 37)
  pA2D.MoveOrigin = pOrigin
  Set pA2D.SpatialReference = pFromSR
  pA2D.Project pToSR
  Set pA2D.SpatialReference = pToSR

  '  Transform and report results
  Debug.Print "----Using MoveOrigin at the same location as the Point to be transformed----"
  Debug.Print "Before Trans, Point X:" & pPt.X & ", Y:" & pPt.Y
  Debug.Print "A2D XTrans: " & pA2D.XTranslation & ", YTrans: " & pA2D.YTranslation
  Debug.Print "A2D MoveOrigin X: " & pA2D2.MoveOrigin.X & ", Y: " & pA2D2.MoveOrigin.Y
  pT2D.Transform esriTransformForward, pA2D
  Debug.Print "After Trans,  Point X:" & pPt.X & ", Y:" & pPt.Y
  Debug.Print qaDoubleCompare(pPt.X, pPt2.X)
  Debug.Print qaDoubleCompare(pPt.Y, pPt2.Y)
  Debug.Print "Comparison,  Point X:" & pPt2.X & ", Y:" & pPt2.Y

  '  Set up Affine Transformation
  '    MoveOrigin is at a slightly different location: Yields slightly inaccurate results
  Set pA2D2 = New AffineTransformation2D
  pA2D2.Move 1, 5
  Set pA2D = pA2D2
  Set pOrigin = CreatePoint(-125, 35)
  pA2D.MoveOrigin = pOrigin
  Set pA2D.SpatialReference = pFromSR
  pA2D.Project pToSR
  Set pA2D.SpatialReference = pToSR

  '  Transform and report results
  Debug.Print "----Using MoveOrigin at a slightly different location----"
  Debug.Print "Before Trans, Point X:" & pPt.X & ", Y:" & pPt.Y
  Debug.Print "A2D XTrans: " & pA2D.XTranslation & ", YTrans: " & pA2D.YTranslation
  Debug.Print "A2D MoveOrigin X: " & pA2D2.MoveOrigin.X & ", Y: " & pA2D2.MoveOrigin.Y
  pT2D.Transform esriTransformForward, pA2D
  Debug.Print "After Trans,  Point X:" & pPt.X & ", Y:" & pPt.Y
  Debug.Print qaDoubleCompare(pPt.X, pPt2.X)
  Debug.Print qaDoubleCompare(pPt.Y, pPt2.Y)
  Debug.Print "Comparison,  Point X:" & pPt2.X & ", Y:" & pPt2.Y
End Sub