Sacred Geography: Astronomical Alignment & GIS

am_equinoxAt Mounds State Park, Anderson Indiana you will find the best preserved Adena-Hopewell earthworks in Indiana.  The 2000 year old earthworks were constructed by prehistoric Native Americans as a place for religious worship and observation of seasonal events.  The presence of these earthworks created a landscape perceived as sacred, which continues today.  fourfeatures

The earthworks at Mounds State Park are referred to as enclosures and have four features: an outer embankment, an inner ditch, a central platform and a gateway. These features are common to these large structures often referred to as sacred circles.

labelsDuring a 1988 survey of the southern ceremonial complex at Mounds State Park, archaeologist Don Cochran noticed that when standing in the Fiddleback Mound he could see another person in the Great Mound through a dip in the embankment.  This is unusual as vision is impaired at other places along the embankment. Further investigations revealed a dip aligning with the Woodland Mound to the west.  These are the only places from which the interior of the Great Mound is visible. Further investigations demonstrated that dips in the embankment also aligned with the summer solstice at the Fiddleback Mound and the winter solstice at the Woodland mound.


This line of sight representation demonstrates visibility from the center of the Great Mound to the Fiddleback mound.  The red lines represent areas not visible to the observer and the green lines visible areas. I put this to the test. I had my daughter stand in the middle of the Great Mound. She put her shirt on a stick and then I walked around the mound and verified that these two dips are in fact the only places you can see into the Great Mound.

A side note to the research…I tested this theory early in the morning. We had forgotten to bring a cloth to put on the stick she would hold up. I told her to use her shirt since she was wearing a sports bra. I’ve seen women running in these and thought “not a big deal”. Well it was to her. She was a little insecure about it. I reassured her it was early and no one would see her anyway. By the time I got back around to the front there was a group standing in the entrance. I did recue her and laughed uncontrollably. Poor kid, I do anything for research.

as_equ_flat2ArcScene provides 3-D representation and animation of the landscape which is invaluable to geographers, planers and landscape architects; however, this application had rarely been applied to archaeological or historical sites.  The application of 3-D and animation to prehistoric sites provides archaeologists with a tool to examine and interpret prehistoric landscapes as they were in the past.  Of course, this may not provide a completely accurate representation, nevertheless, the use of spatial analyst and 3D analyst can aid in interpolating past landscapes by adjusting for rates of erosion and variations in vegetation.  This will aid the archaeologist in planning fieldwork, analyzing data and instruction. 

References: Geopiety and Landscape Perceptions at Mounds State Park, Anderson, Indiana by Barbara A Perry