[GIS] Performing QGIS Datum Transformation from WGS 1984 to NAD 1983

coordinate systemdatumnad83qgiswgs84

Is there a way to transform a shapefile's datum from WGS 1984 to NAD 1983 in QGIS 2.18.0?

In the picture I have attached, the green dots are points that were collected in the field using a Trimble R2 receiver, which by default, collects coordinates in WGS 1984. The red dot is a benchmark with known GPS coordinates and is projected, along with the rest of my shapefiles in NAD 1983 StatePlane Virginia North FIPS 4501 Feet. Optimally, those green points would fall directly on top of my benchmark, but those points fall about 3.5 ft north of my benchmark. I believe this is due to the fact that they are projected in WGS 1984, while the rest of my shapefiles are in NAD 1983.

So far, all I can find in QGIS is ways of re-projecting the CRS. I believe what I need is a datum transformation. I am aware of the "Default datum transformations" tab within the QGIS settings, but if this is the solution to my problem, I cannot figure out how to use it.

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Best Answer

You may try to perform these steps:

  1. Create new QGIS blank project;
  2. Only load the shapefile which has the WGS84 as CRS;
  3. Right-click on the loaded layer from the Layers Panel and click on Save As...
  4. From the dialog, choose a name for the output layer and set the desired CRS;
  5. Create a new QGIS blank project and load both layers: they should be aligned.

I tested this procedure and it works well when dealing with projected CRS, but it could work also for different datums (I hope not being treated as a heretic after this assertion!)

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