How to convert between high and low precision spatial references

SummaryThis article shows how to convert a low-precision spatial reference (pre-9.2) to a high-precision spatial reference.

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Additional Requirements
  • This article assumes your project includes references to the ESRI Geometry assembly.

Converting between high and low precision spatial references

The following code example shows how to convert between high and low precision spatial references:
 

[C#] 
private void LowHighConversion_Example(IFeatureClass pre92FeatureClass)
{
IGeoDataset pre92GeoDataset = pre92FeatureClass as IGeoDataset;

ISpatialReference pre92SpatialReference = pre92GeoDataset.SpatialReference;

double falseX;
double falseY;
double xyUnits;
pre92SpatialReference.GetFalseOriginAndUnits(out falseX, out falseY, out xyUnits);

System.Windows.Forms.MessageBox.Show("Low precision coordinate grid definition:\n" +
"false x: " + falseX + ", false y: " + falseY + ", scale factor: " + xyUnits);


ISpatialReferenceFactory3 spatialReferenceFactory = new SpatialReferenceEnvironmentClass();
ISpatialReference spatialReference92 = spatialReferenceFactory.ConstructHighPrecisionSpatialReference(pre92SpatialReference, -1, -1, -1);

spatialReference92.GetFalseOriginAndUnits(out falseX, out falseY, out xyUnits);
System.Windows.Forms.MessageBox.Show("high precision coordinate grid definition:\n"+
"false x: " + falseX + ", false y: " + falseY + ", scale factor: " + xyUnits);
}

[VB.NET] 
Private Sub LowHighConversion_Example(ByVal pre92FeatureClass As IFeatureClass)
  Dim pre92GeoDataset As IGeoDataset = CType(pre92FeatureClass, IGeoDataset)
  
  Dim pre92SpatialReference As ISpatialReference = pre92GeoDataset.SpatialReference
  
  Dim falseX As Double, falseY As Double, xyUnits As Double
  pre92SpatialReference.GetFalseOriginAndUnits(falseX, falseY, xyUnits)

  System.Windows.Forms.MessageBox.Show("Low precision coordinate grid definition:" & ControlChars.NewLine & _
  "false x: " & falseX & ", false y: " & falseY & ", scale factor: " & xyUnits)

  Dim spatialReferenceFactory As ISpatialReferenceFactory3 = New SpatialReferenceEnvironmentClass()
  Dim spatialReference92 As ISpatialReference = _
  spatialReferenceFactory.ConstructHighPrecisionSpatialReference(pre92SpatialReference, -1, -1, -1)
  spatialReference92.GetFalseOriginAndUnits(falseX, falseY, xyUnits)
  
  System.Windows.Forms.MessageBox.Show("High precision coordinate grid definition:" & ControlChars.NewLine & _
  "false x: " & falseX & ", false y: " & falseY & ", scale factor: " & xyUnits)
End Sub


See Also:

How to construct a high or low precision spatial reference