In ArcGIS 10.1 (advanced lisence) I have imported the plan of a site. The plan has no coordinates, and I couldn't georeference the plan since it has undergone changes during the last 30 years. So, the map has no spatial reference. I used polygons to vectorialize some features I am interested in. Since my ultimate goal is to perform some spatial statistic analysis (e.g., calculating Moran's I for a numeric attribute stored for each feature), how can I devise an arbitrary coordinate system for the site in order to be able to use distance-based statistics?
As for earlier similar question: a somewhat similar question here (projection and coordinate system for non georeferenced archaeological site) got no replies. Further, another often-quoted thread of this forum (Using customized Coordinate System in ArcGIS Desktop?) does not address my issue. At the best of my understanding, what is suggested there entails that "...You have to know the geographic coordinates lat_0 and lon_0 of the origin of your CRS". This does not seem to apply to my issue since I do not know the coordinates of the origin of the coordinate system.