Use the latest version of Circos and read Circos best practices—these list recent important changes and identify sources of common problems.
If you are having trouble, post your issue to the Circos Google Group and include all files and detailed error logs. Please do not email me directly unless it is urgent—you are much more likely to receive a timely reply from the group.
Don't know what question to ask? Read Points of View: Visualizing Biological Data by Bang Wong, myself and invited authors from the Points of View series.
5 — 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>