In what situation, a line feature could not be visible in PgAdmin?

[Shaozhong SHI <shishaozhong@xxxxxxxxx>]

I simply did the following:

 

Get intersections through self-joining lines table where a.fid not equal to b.fid

Put buffered intersections with geometry from lines table together to view.

Some odd things were observed.

Buffer turned up, but supposed lines did not show.

Why does this happen?

Regards,

David