19 votesJohn Lunn commented
I was hoping to make a best fit translation because if you compare the coordinates of the plan points to the local points it will not be the same shift for each set of points.
The reason for this is that we are required to match astronomic bearings on older legal plans in the Land Title Office. In many instances these astronomic bearings can differ from survey to survey depending on where the bearings are derived from, survey errors, etc.
Currently I shift the control onto the legal points which creates a coordinate system for that survey, if I use the same control and go to a different area once I shift the control onto the legal again it creates a new system that is just a little bit different than the first system. Each subsequent survey would require the same process causing the same point to have different coordinates depending on the legal information used to shift the control.
The simple solution would be to put everything in UTM bearings. On plans that we can submit to the Land Title Office (subdivision plans, posting plans, etc.) we do submit using UTM bearings. It's more on topo plans, mortgage certificates, sketch plans, and other unofficial plans that we produce for clients that we must match astronomic bearings even though the control is in UTM.
I was told that the field genius software had this option but I've never used FieldGenius myself so I am not to sure. I've also never heard of the clusters tool.
Also I would have to go through the iterations myself if I found a few points that were disagreeing with the overall fit and decided to throw them out and calculate a new shift. This wouldn't be fun, and would most likely lead to errors. Currently I just rotate the control onto the legal points, I am looking to get away from that if at all possible so I can have everything on one coordinate system but still match legal plan bearings.