turkey (country) doesn't show up in visitors map when visitor filter is enabled, allthough the visitor is counted and visible as turkish in the visitor details and matches the filter. This happens in my case when a custom adwords visitor filter is enabled.Without visitor filter turkey shows up.
Thanks for the report. Maybe you could paste screenshot to show the problem with/without segment?
Also please check you enabled Geo location http://piwik.org/docs/geo-locate/
Hi unfortunally I'm not able to reproduce the problem above exactly as described, probably because it was intraday data. But, A Problem still exists with turkey visitors and segment.
The GeoIP is installed and enabled (GeoIP PECL) see screenshot:
Thanks for follow up, one visit less could be explained by the segment you created which may not include the turkey visits.