So my task is to get onsite Sunday and examine a number of parcels of land to see if there are any big issues before my client decides to purchase. I'm not the only one involved, as there are title, engineering, environmental and water people going over the property. My problem is that there is at least 100 courses for these parcels and associated monuments. I can't of course get through all that in one day, but I can look at all the photos and records and eliminate areas I don't need to look at, such as the highway right of way (deal with that later), state/fed boundaries (not much to do with those), a large river boundary (the photos will get me close on that) which eliminates 70 of the corners. I figure I need to look at 25 monuments and occupation and identify problems.
Get it done in a day?
Maybe.
Might take a couple.
One way it's possible is that the big parcels were all surveyed, and DOT also did a survey and tied common Section corners with Grid Coordinates.
That was during the metric days, so I have state plane grid to compare with the plats.
I have a choice, try to rotate and shrink the plats to SPC, or use the LAT, LONGS from the DOT survey to design an LDP.
Because I want to have the plats with me and I don't want to deal with rotations I decided to do an LDP on the surface and match the plats, they don't say what system they are on and the best I can figure out is that they are on some coordinate system developed by that firm and extended to this location.
Common monuments show the SPC grid azimuths to be -22 minutes from a true north bearing and the parcel surveys to be -12 minutes.
The site is east of the Central Meridian. The section corners are on a line 29 minutes of longitude east.
So by using that ratio 29/22*10+site Long I design an LDP (TM) with that line of longitude as the CM with a latitude nearby.
Didn't quite work, took a couple of tweaks and I have an LDP projection with the section line having the same bearing as the parcel plat, I used elevations from GOOGLE to get a Scale Factor for the LDP which turned out to be 1.000177.
Between the two section corners using lat, long from DOT I get a ground distance of 5261.70' and a grid distance of 5261.70'.
The SPC distance is 5260.35, and the plat distance is 5261.76.
Now the plats can be calculated without rotating, or shrinking and I have a projection that can be used anywhere in the four sections, I'll be working in.
