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I was hoping to be able to use Reproject.ReprojectPoints to achieve a datum shift between lat/lon values in NAD27 and NAD83. I'm able to correctly reproject from NAD27 lat/lon to NAD27 UTM and from NAD83 lat/lon to NAD83 UTM. But when I try the following, I just end up with the same coordinates in the output. I'm obviously misinterpreting the functionality, but is there a way to add a Helmert transformation or to mimic the NAD con functionality in Proj4 using dotSpatial? I'll do what it takes, but am trying to work smart and not reinvent the wheel.

Thanks for any comments.

ProjectionInfo source = KnownCoordinateSystems.Geographic.SpheroidBased.Clarke1866;

ProjectionInfo dest = KnownCoordinateSystems.Geographic.SpheroidBased.GRS1980;// KnownCoordinateSystems.Geographic.SpheroidBased.Clarke1866;

var xy = new List<double>();

var z = new List<double>();

double lat = 29.48438;
double lon = -93.81992;




var xyA = xy.ToArray();

var zA = z.ToArray();

Reproject.ReprojectPoints(xyA, zA, source, dest, 0, 1);
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The answer from developers – nadya Mar 13 '13 at 7:05

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