Using GIS - Trail of Tears


Using GIS to uncover lost sections of the Trail of Tears

As a result of the Indian Removal Act of 1830, the United States government forcibly removed more than 16,000 Cherokee Indian people from their homelands in Tennessee, Alabama, North Carolina, and Georgia, sending them to the Indian Territory (today known as Oklahoma). The impact on the Cherokee was devastating; hundreds died during their forced migration, and thousands more perished from the consequences of relocation. This tragic chapter in American and Cherokee history became known as the Trail of Tears.

The Trail of Tears National Historic Trail commemorates the Cherokee experience and identifies the paths that 17 Cherokee detachments followed westward. Today the trail encompasses about 2,200 miles of land and water routes, and traverses portions of nine states. The Arkansas Historic Preservation Program (AHPP) is working with the National Park Service and the Trail of Tears Association, as well as with State Historic Preservation Offices in other states, to identify and preserve properties associated with the Cherokee Removal of the 1830s.

The traditional method of finding historic features has involved a combination of the written record and maps from the time period. Using references of locations mentioned in the original sources the researcher can locate the historic features on maps, either modern or historic. The problem lies in identifying features located between the known points. We have historic maps showing the areas between the reference points but that will usually only cut the search radius down to several miles. Even with several volunteers assisting, locating a 170-year-old feature can be difficult if not impossible.

To find sections where the road is uncertain we have established a geographic information system (GIS) to assist us. With the use of historic maps, photographic imagery and elevation data we have uncovered some lost sections of the Trail of Tears. Some tools we used included the use of ArcGIS with Spatial Analyst and 3D Analyst, ArcPAD with a GPS, DOQ's, geo-referenced historical maps, historic databases, and 3D visualization.

One of the oldest research tools has proven to be the most useful: historic maps. Historic maps tell us how an area developed, they identify where historic events took place, and sometimes even describe the character of the landscape. Modern and historic maps can be used together to help historians decide where to survey for historic or archeological resources or where to create historic easements.

By georeferencing these maps they can not only narrow the search but can often pinpoint the objective. Once a map is georeferenced it can be used to overlay modern maps or can be loaded into a GPS. The AHPP uses both methods in research but in the field the historic map in a GPS is unsurpassed in achieving results. The accuracy of 140-year-old hand-drawn maps can be surprisingly good even though accuracy wasn't always the highest priority to the cartographer who made them. There have been several times that the GPS lead us to within 10 feet of a feature.

The challenge is in georeferencing a map that is not based on a public land survey system or known boundary, with other concerns including proper scale and correct orientation. Several methods have been used to georeference these maps the first is to check for structures and compare those with the AHPP's historic structure database. Next a search is conducted for place names. On some difficult cases mountains and rivers are used as references. Rivers are usually a bad source for referencing because of meandering but if you have a georeferenced map from the same period and area it can work. Using digital elevation models (DEM) to produce hillshading can bring to light previous paths of a river. Even a poor georeferenced map can reduce the search area. The georeferenced map in the office can be overlaid on a color infrared digital Ortho Photograph and occasionally the feature being sought is revealed. Infrared reflectance will often reveal old road bed as long as there isn't too much tree cover.

Through the use of our GIS we have been able to find and record numerous sections of the Trail of Tears. Once we have these sections verified and recorded with the GPS we send our changes to the National Park Service. Our work will hopefully help interpret and improve the Trail of Tears National Historic Trail. In addition to the Trail of Tears, the techniques and historic maps we have collected will aid us in future research of historic features, cultural resource management, and Section 106 review processes.

For more information, contact:

Department of Arkansas Heritage