Event

The EVENT table includes metadata fields defining the location for sampling or measurements (synonyms: site, station). Double click on an event label in 4D will open the event window showing the fields on two cards: Basics and Details. If data are georeferenced, the event label and latitude/longitude are mandatory.
 * A SINGLE EVENT can be defined directly by clicking on the New button in the Event list window and information is typed in the given fields.
 * To add a LIST of EVENTS, use the import form for events . Export from excel as tab-delimited text-file and import via 4D-Menue File/Import, choose Sites/Events. Below find a description of the fields in the event table; recommendations on how to fill out the columns in the import form are given in italic.
 * If an event has NO position (e.g. name of an experiment), Latitude and Longitude can be import with values -999.999; consequently the position will not appear in the metaheader.
 * If NO EVENT is required, use the virtual event not_given in the data import file. In this case, the event line will not appear in the metaheader.

Basics tab
 * Event label is the name of a sampling/measuring event; it should not contain blanks and must be unique. This can be ensured by combining the station numbers with the campaign label, using an underline to join (e.g. Taymyr97_3). Devices or projects should not be replicated in the label (avoid redundancies).
 * Optional label may be used, if the same station as different labels (see Event label problem)
 * Device tool, gear or method used to take a sample or to make measurements; use not_given if not available; relational to table Device; use Abbreviation as defined in the device table for import (column headed 'Gear').
 * Device type is used to group devices and set automaticaly
 * Latitude is mandatory for georeferenced data, display format can be changed in the Menue File/Preferences/Geographical positions
 * Longitude dito
 * Elevation relative to sea level: positive above sea level, negative below sea level (i.e. water depth)
 * Date of event execution
 * Time of event execution
 * Recovery is a special field only used for coring; gives the length of the core in [m], otherwise filled with -999.999

Details tab
 * Latitude, Longitude, Elevation, Date, Time are repeated from the Basics tab.
 * in case an event is a profile, having a start and an end point, all fields are repeated also to describe the second point with a '2' added to the corresponding field name.
 * Penetration and Recovery are fields for coring, see recovery.
 * Project, Campaign, Site, Area are relational to the corresponding tables.
 * Comment may be used to add any event specific text. If an unvalid position is imported, the text Unknown event! is added to the comment field
 * Keywords is relational to the thesaurus and may be used to define specific groups of event.
 * URI link to a more detailed description of an event, e.g. on a web page or a document.

Event label problem: there is a great risk of confusion with event labels. Please consider that clarity for the relation between event and data is paramount for the curator and the import procedure. The event labels published in the expedition report should be exactly those that appear in a publication and in the data sets provided for import (first column). In some cases, an additional labeling of events can not be avoided; in this case please use the field Optional label in the event table to add a second label. In the final data set, it will appear behind the event label in parenthesis.

Three different systems exist for labeling events during expeditions:
 * 1) ship related (e.g. Vema, Polarstern)
 * 2) institution related (e.g. GIK..., Geob...)
 * 3) free format

As a well defined example, the station labeling system of Polarstern is described as:
 * Station labels start with PS as a reference to the ship.
 * Each expedition is numbered starting with 1 and written with a leading zero; e.g. PS07 is the seventh expedition.
 * Station numbers start with 1 on each new expedition and are numbered throughout, independent from the legs, leading zeros to fill a three digit number; e.g. PS07/025 is the 25th station during the 7th expedition.
 * During a station, several devices may be used (events), those are identified by an increasing number added with a hyphen, e.g. a complete event label would be PS07/025-3 labeling the third device on the 25th station during the 7th expedition.
 * Measurements along the track have an event label like PS07/1-track.