I am using ArcMaps 10.3 and know just enough to get into trouble. I went to upload line shape files into a Garmin Montana GPS unit (through the DNR GPS application from Minnesota DNR), and discovered that most files are projected in stereographic south pole. I didn't even know that was a projection, and have no idea how it happened, especially since we have transferred these files to the GPS before with no problems. When I checked the projections of the layers in the map I'm trying to upload, I found out that there were a combination of three GCS and projections. All of the layers match on the map in the program, but not when I upload the files into the GPS. I have two questions:
1. How could the projection be changed to something so seemingly random? (If it had been WGS 1984, NAD 1983 or even Nebraska State Plane, that would have made more sense as those are the GCS/projections I use.)
2. Is there a simpler way to fix it than redrawing each line and saving it as a shape file with the corrected projection? I tried define projection and project tools, but neither matched up with the map or uploaded in the GPS correctly.