Merging Coordinate Systems
25-30 years ago I did some surveying for a boundary. The survey was started on a NGS point using NAD27 coordinates. The AZ mark was backsighted and then traverses headed north and west from the point which was near the SE corner of the “parcel”. From there I ended up laying out control and checking back into myself adjusting traverses and building a complicated set of figures as the survey went north and west.
Now I’m faced with going back up and adding an additional 7 miles of line inside the boundary. But of course I’m not using a 301B but R8s.
So, I established a coordinate set using the NGS point datasheet, then guessing at a scale and scaling around the point. After setting onsite Friday I located a few corners and laid out a mile and half of line. Taking the data back and fixing to the local CORS point I “checkin” N89-30E, 0.62′.
I wasn’t expecting that, this point is 45000′ northwest of the starting point.
I also had to change the NGS datasheet coordinate to the original NAD27 coordinate in my file, not sure if that would have made it better or worse.
Nice to see the old coordinate system can work that well with new GPS control.
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