If you are not taking your temperature at the same time every day or if there are other external factors affecting your chart data, (drinking, medications, travel...) there is a good chance that you ovulated without your chart showing it. If this is the case, a change in charting habits will usually allow you to see your ovulation pattern in subsequent cycles. Using OPKs in addition to tracking your other fertility signs may help.
If you are sure that you are charting accurately and there is no sign of ovulation on your chart, you should assume that you are still waiting for ovulation, especially if you typically have long cycles. Keep on having intercourse when you see signs of increased fertility, particularly fertile cervical fluid, as ovulation may just be delayed.
Some women typically ovulate late in the cycle, while others may have delayed ovulation due to stress, illness, travel or other factors. You can't tell whether or not the cycle will turn out to be anovulatory until it is over so it is best to assume that you are still waiting for ovulation so you don't miss a chance to conceive.
The occasional cycle without ovulation is usually not cause for concern. If you have several charts that do not show an ovulation pattern, however, or if you suspect that you may not be ovulating, you should talk to your doctor.