||I have a line from A to B, 272 km along a line of latitude (59°). This is a fishing area boundary south of Prince William Sound, Alaska. The line is between two points in a point file. When I trace part of the line in WGS_1984_PDC_Mercator and subsequently change the data frame projection to Alaska_Albers_Equal_Area_Conic, the traced line segments no longer align with the parent line. If I start at either end, the origin of the segment and parent coincide with the point file location but the “free” end of the segment is south of the parent line. If I trace a segment of the line in the center of the parent line, it moves “parallel” but south 2.3 km of the parent line when I change the data frame projection. If I trace the whole line length from point to point it aligns perfectly with the parent from end to end, in both data frame projections. If I snap a line from point to point rather than tracing it aligns perfectly with the original line from end to end in both data frame projections. If cut the end-to-end-perfectly-aligned-in-both-projections-traced-copy, leaving a segment in the middle of the parent line and change the data frame projection it moves in the same direction and magnitude that the traced segment does. Is there a way to have the segments and the master line stay in alignment?
The entire rest of the closed polylines, that these latitude lines form the southern boundary of, stays in perfect alignment in all data frame projections.