Heterodyne mapping is done by offset pointing the telescope. Especially for larger maps, OTF mapping is more efficient for larger maps because a common reference position is used for all the cells in each row.

1. Point by point mapping using position switching with a specified reference position. This example uses looping commands to make a 3 x 3 map in equatorial coordinates with 15 arcsec spacing.
   uip> for i 1 to 3
uip>   rao /map (i-2)*15
uip>   for j 1 to 3
uip>    deco /map (j-2)*15
uip>    oo_scan N /designated_off
uip>   next
uip> next
   • At each map position, the telescope will move asymmetrically
     OFF ON
   • N is the number of repetitions of this pattern.
   • The reference position must be specified in the source catalog as target:off_position.
2. Same example but without the looping commands.
   uip> rao /map -15
uip> deco /map -15
uip> oo_scan N /designated_off
uip> deco /map 0
uip> oo_scan N /designated_off
uip> deco /map +15
uip> oo_scan N /designated_off
   etc.