The Next Generation: My Biggest Learning Experience Yet
Professional Surveyor Magazine - April 2008
I recently finished a project with a lot of new road blocks for me—it was one of those projects that's extremely frustrating yet, in the end, teaches you the most and makes you better at what you do.
The project was a boundary retracement survey that we in the office lovingly called "The 67 Acres." We started it in September of 2007, and in the process our client sold the property, which meant the project had to be put on hold until a new contract was written and signed. Once that was finished, hunting season rolled around, and the client preferred that we wait until hunting season was finished to proceed with the rest of the survey. The next in a long line of problems was that the property was extremely wooded, and the client gave us permission to wait until all of the leaves had fallen from the trees. So, after hunting season, the falling of the leaves, the holidays, and some bad weather, we were finally able to sink our teeth into collecting data in January 2008.
Back in September, I had plotted all of the current record descriptions for the subject property and adjoiners, and the majority of the research had been done. But when we restarted, that had been several months back, so I had to refresh my memory with the project by once again going through the deeds of record and the little bit of data that had been collected at the site.
One of the unique challenges that poked its head out with this boundary retracement survey in the beginning had to do with the record description of the subject property. The description was fairly old and written in poles, and I have found that most descriptions written in poles do not typically close mathematically but are retraceable based on the controlling calls. The mathematical misclosure of this particular description was approximately 700 feet, and it was difficult to ascertain if there was a particular call within the record description that was wrong but all the others agreed, or some other problem like that.
There were controlling calls to trees and posts, but being that 99 percent of the boundary was wooded, finding the trees called for in the deed with no bearing or distance to get us in the general vicinity made retracing the boundary extra difficult. Basically, we were left with the adjoiners' record descriptions and the approximate area based on a survey referenced in the deed for the subject property, and unfortunately we were unable to locate that survey. Based on the ambiguity in the subject description, the adjoiner's descriptions were used to retrace the boundary.
Aside from having problems with the record description for our subject property, we also had some technical difficulties on the site. As I mentioned, most of the property was wooded, but there were parts that were fairly clear, which meant that we would be able to use GPS relative positioning techniques as well as conventional radial data collection techniques. We had hoped that using GPS would save us time, and in the end it most likely did, even amidst a technical problem that sent us back to the site for an extra trip.
This technical issue had to do with coordinate systems, and we learned much from it. Since beginning my career in Tennessee, we have worked a lot of sites where we use both GPS relative positioning techniques as well as radial data collection techniques, but not many where we have had to make an extra trip and were able to use GPS on the second trip. When the crew sets up and prepares to use GPS, they typically assume a "here" solution, but they collect data with the base receiver so that we can submit the data to NGS and obtain an OPUS solution. Typically the "here" solution will be within approximately seven feet of the coordinates obtained from an OPUS solution. This means that once we download the data collected using GPS and bring it into AutoCAD, we will then move it to the OPUS solution and scale the coordinates from grid to ground. We then immediately move the data to a local coordinate system, since it is no longer in state plane once we have scaled the data.
Well, the GPS collected data was scaled to bring in the rest of the data collected using a total station and data collector so that they would all be referenced to ground distances. We ended up going back out to the site and using GPS, and I had moved the data back to state plane coordinates and scaled them back to grid. The main problem ensued from that point. The field crew worked in two coordinate systems. When they set up the GPS they used the original coordinates from the "here" solution and keyed in the coordinates I had given them based on the OPUS solution. I had been checking the field notes and coordinate listing when I noticed the error. Luckily I had caught the error before bringing the points into the project.
When we thought we were finished we realized that the points that had been staked with GPS were incorrect, and thus we had to make another trip to the site. I managed to salvage the data they had collected that day because it was on the "here" coordinate system, which I was able to move to state plane coordinates based on the OPUS solution. This cost us time and money because we had to make an extra trip to the site to reset approximately six points across the 67 acres. We learned an invaluable lesson in communication that day.
"The 67 Acres" project was actually one of my favorites because of all of its problems. It was one of the first sequential conveyances that I had worked on, and it presented an interesting application of the Order of Importance of Conflicting Title Elements based on common law rulings. It also taught us how important those checks and balances are. No matter how much you trust yourself or your field crew, we are all still fallible. There were days when I was extremely frustrated and wanted to pull out my hair, but in the end I realized that these are the projects where my appreciation for the profession grows and I gain the most knowledge.
About the Author
Ashley Rose-NalinAshley is a recent graduate in land surveying and geomatics engineering form Purdue University and a newly licensed surveyor in Tennessee.
» Back to our April 2008 Issue