[postgis-users] Help with spatial query

[Brent Wood]

I'm trying to make sense of the various spatial operators. I need to join a
table of cells to a table of lines, to create a table where there is a record
for each case where a line passes entirely or partially through a cell.

Looking at the OGC specs was a bit of help, but can anyone explain the
difference between the intersects, overlaps & crosses functions:

ie:

select 
.... 
where
  lines.geom && cell.geom and
<one of>
  intersects(lines.geom, cell.geom)
  overlaps(lines.geom, cell.geom)
  crosses(lines.geom, cells.geom)

I figure I should be using crosses for this query, but don't undertand the
distinction between these.  


Thanks,

  Brent Wood