The Corner Connection
When I started as chief surveyor with the Office of the Fulton County Engineer in Ohio in late 2005, I discovered a large spreadsheet with hundreds of section corner and property controlling corner data. This data was shot with GPS over a span of 10 years by many different field personnel, stored by State Plane Coordinates and indexed by a unique corner code. The corner references were written in a series of small books overtop older references.
To best follow chapter 315.25 of the Ohio Revised Code specifying that “the county engineer shall make and keep… an accurate record of all surveys,” I immediately began reorganizing the data, creating new corner codes and corner sheets, new computer file structures and new standards for field corner occupation, eventually creating the GIS that exists today. By applying hotlinks and performing query functions within the GIS, I can manage and analyze the survey corners within the county.
Fulton County's Survey History
Northwestern Ohio comprises two original General Land Office (GLO) surveys. These include the surveys north and east of the First Principal Meridian and Baseline, and part of the Michigan Meridian and Baseline. The First Principal Meridian is the western boundary of the state of Ohio and originates at the Greenville Treaty Line, then heads north. This meridian controls all the ranges easterly into northwestern Ohio. The Baseline was marked at or near 41 degrees north latitude to control all the townships heading north into northwestern Ohio. The Michigan Meridian starts at Fort Defiance on the Maumee River in Ohio, and is projected due north, controlling Ranges East and West. The Michigan Baseline is just north of Detroit and controls the townships heading south into northwestern Ohio.
William Harris first surveyed the state line between Ohio and Michigan in 1817. Michigan disputed the line, which led to the resurvey by John Fulton in 1818. Due to the vague description within the original Northwest Ordinance of 1787, the difference in the two surveys was approximately 400 square miles, and included the current city of Toledo and the mouth of the Maumee River into Lake Erie. To compromise, the state of Ohio was granted the 400 square miles of disputed territory, and Michigan was given approximately 9,000 square miles of what is today the Upper Peninsula. With this agreement, Michigan was also granted admission into the Union in 1837. The Harris Line was retraced in 1915 and marked with granite boundary posts.
The GLO surveys were performed between 1819 and 1821 by deputy surveyors including Joseph Wampler and John Mullett. Since Ohio was the testing ground for the Public Land Survey System across the United States, northwestern Ohio is an example of the end result. In Ohio Land Subdivisions, C.E. Sherman wrote: “The survey of this region was the last of the Government’s experiments with systems of division in Ohio, and the general plan of survey there adopted has since been used over the vast expanse of our public domain west to the Pacific Ocean.”
The variation of these two different surveys makes for sometimes complicated fieldwork and more complicated research. While researching original GLO land patents in the northern part of Fulton County, the disputed territory of Ohio and Michigan, one has to look for land patents from the former Monroe, Mich., GLO office.
Coordinating the CornersFrom the large spreadsheet of section corners and property controlling corners, I decided to create 24 separate spreadsheets, one for each congressional township within the limits of Fulton County. I also created six additional spreadsheets to hold the data for the federal bench marks located within the county. Each spreadsheet was made into a table within ESRI (Redlands, Calif.) ArcView and hotlinked accordingly.
The process of hotlinking in ArcView simply links a feature, within a view, to a specified data source. The process simplifies research by clicking on a feature and instantly seeing the data. Research time is cut to a fraction and errors are eliminated.
The spreadsheets for the land corners include point number, northing, easting, corner code, monument type, date of occupation, date last referenced and path name. The date last referenced is necessary to perform query functions and the path name is for the purpose of hotlinking within the GIS. I did not include any vertical data for the land corners due to road resurfacing and inaccuracy of the vertical data. The spreadsheets for the federal control include point number, northing, easting, current elevation, monument type or federal designation, date occupied, path name and subsequent survey elevation.
Each spreadsheet was completed by researching the appropriate information and filling in the blanks on the new spreadsheet. Each corner now has its own corner code and permanent point number within its own spreadsheet. As I field locate, or densify, the land corners, I then update the appropriate spreadsheet. During the winter months I scan in the appropriate reference sheets and hotlink them accordingly, thereby continuously updating the GIS.
The completed spreadsheets are then imported into ArcView where the corners can be managed and analyzed. By utilizing the query tool, one can identify all of the corners that have not been referenced since a certain date. For statistical purposes, one can also identify all the corners that have been referenced in a certain year.
Referencing the land corners in the county is done before and after asphalt resurfacing, and the appropriate reference sheets are then updated with the current data and managed within the GIS. Every year the survey department is given a master list of all the county and township roads to be resurfaced. Research is completed on each corner, and a new corner sheet is created. Every corner is referenced in the field with a steel tape before asphalt resurfacing, and every corner is then reset with a steel tape using the references after the resurfacing. GPS is used to check the position and in case all other references are lost in the future.
Creating New Reference SheetsDuring the process of referencing corners at the start of the project, I decided to create a new system. Prior to my arrival, crews updated a series of 12 small “reference” books divided between the 12 political townships. The problem with keeping the corner references indexed by political township is that the townships change over time. The original congressional townships will never change and are more pertinent to surveying and record keeping. The crews erased the old data and wrote in the new reference ties. Unfortunately, years of prior information have been lost due to this process; luckily, some older copies have been made to aid in research.
The new reference sheets I created are based on Michigan’s Land Corner Recordation Certificates as found in Public Act 74 of 1970. I try to show a detailed history of the monument and its perpetuation through history. This way, no one can dispute the position of the corner because it can be proven with its older references. I slightly simplified the form by only including prior references rather than including every surveyor who has used the monument throughout history. Historically, Fulton County has a strong history of land corners; the disputes over corners that other counties and states have are few and far between.
I used Microsoft Word for these forms for simplicity and for the ability to save the document as a .tiff image. I can then save and hotlink all data from my office without printing and scanning, therefore saving steps and making the process a little quicker. Looking to the future, I can also easily update the Word document and work through the same procedure for new corner sheets. I list the pertinent information on each corner sheet, such as the town, range, corner code, permanent point number, and the older and newer references. I also have a space for any notes I may want to add.
The corner sheets are fully researched and printed off prior to referencing. When the time comes to reference, the survey crew can then check any and all of the references as they were set over the years. This gives a solid check to perpetuate the corner position. After referencing, the new corner sheet is updated with any new references, and the corner sheet is saved and printed for filing. The new corner sheet will then show up with the hotlink tool in ArcView.
The end result is a “clean” GIS with survey grade information. I can point and click on any corner or control point to find information about it. I can also view an image of the reference sheet and print it accordingly, saving research time. This is a very visual tool. I can overlay current aerial photography, streams, roads, section information, parcel lines and many more layers thanks to the GIS department at our county auditor’s office. The Fulton County GIS will be updated on a daily basis for years to come, offering much ease to anyone doing research.
The Importance of MetadataAs with any good GIS, if you are presenting data, you must present data about that data (metadata). The metadata for the coordinates within the Fulton County Survey Corner & Control GIS are based off the Ohio State Plane Coordinate System, Ohio North Zone – 3401, NAD83 (86), U.S. survey feet. It is not only important to name the State Plane Coordinate system you are in, but which zone you are in as well. The project may lie next to two separate zones, so it is necessary to be very specific. If you are working with the NAD83 datum, it is also equally important to clearly identify which adjustment you are using and specify which definition of the foot you are using. This is significant to remember when dealing with State Plane Coordinates because different states have different foot definitions.
The table on page 32 is an example of three different horizontal adjustments within NAD83 on a horizontal monument within Fulton County. These differences vary not only across the county, but substantially across the country.
This example demonstrates why metadata is so important. With the new CORS/VRS system set up across the state of Ohio, the CORS are related to, and the same as, the new NAD83 (NSRS2007) adjustment. But if a surveyor tries to tie into a monument within the Fulton County Survey Corner & Control GIS, without doing his homework, he will be off by approximately a foot and a half. I plan to resolve this issue by converting all of the existing data (approximately 1,300 land corners) into the new NAD83 (NSRS2007) adjustment. By doing this, the GIS will be consistent with the CORS and the new federal adjustment.
With the incorporation of this GIS in Fulton County, along with its ability to be on true State Plane Coordinates, no corner, referenced or not, will be lost again.
BOUNDARY POST 32 MI OH
LATITUDE 41 42 43.75607 (N)
NORTHING 749547.221 U.S. Survey Feet, Ohio North Zone 3401
LONGITUDE 084 09 30.35893 (W)
EASTING 1515705.833 U.S. Survey Feet, Ohio North Zone 3401
BOUNDARY POST 32 MI OH
LATITUDE 41 42 43.74925 (N)
NORTHING 749546.506 U.S. Survey Feet, Ohio North Zone 3401
LONGITUDE 084 09 30.34228 (W)
EASTING 1515707.083 U.S. Survey Feet, Ohio North Zone 3401
NAD83 (NSRS 2007)
BOUNDARY POST 32 MI OH
LATITUDE 41 42 43.74960 (N)
NORTHING 749546.542 U.S. Survey Feet, Ohio North Zone 3401
LONGITUDE 084 09 30.34280 (W)
EASTING 1515707.044 U.S. Survey Feet, Ohio North Zone 3401
Horizontal Difference Between Datums by Northing and Easting
Boundary Post 32 MI OH
NAD 83 (1986) NAD 83 (1986) to NAD 83 (1995) to to NAD 83 (1995) NAD 83 (NSRS 2007) NAD 83 (NSRS 2007)
Northing -0.715 Northing -0.679 Northing 0.036
Easting 1.250 Easting 1.211 Easting -0.039