Circos > Documentation > Tutorials > Ticks And Labels > Single Ticks
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4 — Tick Marks, Grids and Labels

8. Ticks at Specific Positions

Up to now, each tick block defined a tick series, with the positions of ticks in a series defined by the spacing (absolute or relative). In this tutorial, you'll see how to define ticks at specific positions.

Ticks at specific absolute positions

To define a tick at a given absolute position, use `position` instead of `spacing`.

```<ticks>

...

<tick>
# define position
position     = 25u
# no spacing definition necessary
...
</tick>

<tick>
# define multiple positions
position     = 30u,32u,34u,40u
...
</tick>

...

</ticks>
```

Do not define `spacing` when `position` is used.

Ticks at specific relative positions

To place at specific relative positions, use `rposition` and set `spacing_type=relative`.

```<tick>
# define multiple positions
rposition      = 0.5,0.7,0.9
spacing_type   = relative
color          = blue
label_relative = yes
format         = %.2f
</tick>
```

Note the difference between `position` (for absolute positions) and `rposition` (for relative positions).

Do not define `rspacing` when `rposition` is used.

Ticks at start and end of ideogram

Two special positions are defined. These are `start` and `end`. Using these strings you can place a tick at the start or end of the ideogram. This tick can have a label. In addition, you can define the label to be any string by using the `label` parameter. This parameter is supported for all ticks, but is particularly useful for start/end ideogram ticks.

```<tick>
position = start
label    = 3'
...
</tick>

<tick>
position = end
label    = 5'
...
</tick>
```