I got coordinates to old survey data in an Excel Spreadsheet. The coordinate system is unknown. I enter the values into a proprietary system to display them in module using Google Earth. I tried to guess the coordinate systems, since I know roughly the physical addresses of the locations in question, but none of the standard systems plot even remotely accurately. (NAD 83 UTM 11N, State Plane AZ Central/ NAD ft, NAD27 UTM 11 N, etc....)
Sadly, I don't have ArcGIS, and I am stumped. Can anyone help, or recommend some means of ferreting out an answer? Most online forums seem to discuss only shape files.
Here are some examples:
Address: 500 W Laguna St, Tucson AZ Lat: 459579 Long: 9894182 Address: 250 E Roger Rd, Tuscon AZ Lat: 466476 Long: 993325