After inserting the cs99_d90.shp file obtained from the 1990 US Census, I received an error message claiming:
The following data sources you added are missing spatial reference information. This data can be be drawn in ArcMap but cannot be projected.
After reading about several tools, such as the Define Projection tool which requires me to choose a projection from a list of projections that I cannot comprehend, I am hoping there is a much less convoluted solution to this problem. I have the 1990 County shapefile, and I want to layer it over a base map.
How can I solve this problem?
