There is a hook available in the WEC Table Map extension, available at $GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['tx_wecmap_pi3']['markerHook']. It allows processing marker objects as they are added to the map but before the map is rendered. There are two different parameters that are passed into your user function. The second one, the reference, is null and not available. The first is an array of parameters, outlined here.
table | The name of the table that the current record is taken from. |
data | The whole database row of the current record. |
markerObj | A reference to the actual marker object. See the reference for a list of available methods. |