Historically, many land surveys in Indiana (like route surveys, boundary surveys, topographic surveys, construction staking projects, control surveys, etc.) performed in both the public and private sector nearly always use an arbitrary (e.g., “N 5,000.000 E 5,000.000”) or modified State Plane Coordinate Systems (SPCS) to minimize grid (GIS) to ground (Survey) differences. Unfortunately, these arbitrary / modified solutions are different for each project, and create additional work, persistent inefficiencies, and the potential for errors when attempting to georeference this survey data to existing GIS and CAD data.
Indiana is now one of several states that have created a set of new coordinate reference systems to solve this problem. The Indiana Geospatial Coordinate System (InGCS) is a set of new “low distortion” map projection zones for Indiana whose parameters are defined so that linear distortion is negligible. As a result, distances computed between points using the grid coordinate system in GIS or CAD software will nearly equal the actual horizontal distance between the same points surveyed on the ground. The InGCS is designed such that it can be readily used with a wide variety of commercial software platforms for surveying, engineering, GIS, construction, cartographic mapping applications, agriculture, emergency medical, etc.
The InGCS have now been officially approved and adopted by INDOT in 2015 and will soon be the primary coordinate reference system used on INDOT survey and design projects. The InGCS projections are now published in the EPSG database, and geospatial and surveying vendors like Trimble, Leica, Esri, Hexagon, AutoDesk and others are including them is their latest software releases.
Using InGCS provides a seamless [and simple] workflow between users creating geospatial data within different surveying and mapping disciplines and industries, so as geospatial coordinators we need to both understand these and promote the use of InGCS throughout our communities and networks.
Eric N. Banschbach, P.S. and Manager of the INDOT Land & Aerial Survey Office contracted this work to the Lochmueller Group, where Matthew G. Badger, PS, Survey Project Manager, was the LDP Developer for this project.
Please refer to the InGCS webpage at www.in.gov/indot/InGCS.htm for additional information.