Digitized GIS Data - Wrong Coordinate System, Right Location

Question

I (correctly) georeferenced a JPEG to an existing shapefile that was in the correct coordinate system.

I then proceeded to create line feature classes by manually tracing some of the features (roads) from the JPEG.

The mistake: When creating the line feature classes, I used the wrong coordinate system for the feature datasets, and so the line feature classes are all in the wrong coordinate system.

The result is that the feature classes are appearing in the correct location (because I manually traced them over the georeferenced JPG) but are in the incorrect coordinate system. Essentially I need a way to update the coordinate system to the correct projection without changing the location of the lines.

Answer 1

I think you can just redefine the coordinate system. In ArcGIS, it would be the data's property page or the Define Projection Tool.

You probably should try removing any coordinate system ("clear" it) and see if the lines features still line up. If they do, good to go.

If they don't line up, the software may have projected the digitized coordinates (in the JPG's coordinate system) into the coordinate system of the feature class. In that case, you would need to Project the feature classes into the coordinate system you want. The reason that they still line up is that ArcMap or the "viewer" you're using is projecting them on-the-fly to the display's coordinate system.