When selecting the data to export, you can choose to export point references. Set the Export Point References property on the Export tab of the LandXML Settings dialog box to On.
When you turn this option on, Autodesk Civil 3D creates COGO point references, where possible, for the plot, alignment, and surface geometry. This means that, if the geometry of plots, alignments, and surfaces in the drawing match COGO point coordinates within a specified tolerance, the object coordinates are exported to the LandXML file as references to those COGO points.
Point references substitute a known point name instead of using northing and easting coordinates. For example, without a point reference, the start point of a line element is written as follows:
<Start>5447.73530 4525.60643</Start>
With a point reference, it is written as follows:
<Start pntRef="371"></Start>
It is also valid for a coordinate geometry element to have a mix of pntRef and coordinate values as shown in the following example:
<Line> <Start pntRef="250" /> <End>5632.87775298 3944.16966215</End> </Line>
This situation could occur for the endpoint if a COGO point does not exist within the specified tolerance.