Surveying the Possibilities
The Public Land Survey System (PLSS) is the "dominant system of describing and dividing land west of the Eastern seaboard."
It is a legal reference system that splits the country into gridded blocks, and is the original basis for deeds and property lines.
The corners of the gridded areas - known as PLSS corners - are identified by markers placed in the ground or posted on
signs. Many County Surveyors have PLSS corner description cards (also called tie cards), which describe how to find the PLSS corner markers. Few of these markers have been tagged with the GPS coordinates that can be used for legal surveys. Efforts are underway, but the process will take years. In the meantime, surveyors need a simple, reliable way to access the information on the cards.
The statewide Tie Card Project, championed by the IGIC Geodetic Workgroup and the Indiana Department of Environmental Management,
has been underway since 2004. The goal is to scan tie cards and make them accessible in a digital, geographic
format.
A grant program paid for laptops and scanners that can be checked out and used by County Surveyors
to scan their tie cards. Donations of time and expertise from the private sector led to an application that
renames scanned files based on a statewide naming convention. Each digital tie card is then linked to a point
on a computer-generated grid which shows approximate corner marker locations. By clicking on a point, you can v
iew that tie card.
IGIC and IDEM partnered with the Indiana Geological Survey to make the Surveyor Tie Card layer
(with scanned images of the Tie Cards) available on the
GIS Atlas for Indiana website.
Results
- Tie cards are associated with a logical statewide grid point system, making them faster and easier to find
- Data is archived offsite, providing much-needed redundancy in case of fire, flood or other disaster
- The information will be accessible from any computer with an internet connection, any time
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