Boat users and fishers: Is your GPS up to date?

GPS, an acronym for global positioning system, relies on a network of satellites that broadcasts timing signals by radio to GPS receivers.

GDA94 refers to the national map and chart datum that is compatible with current GPS systems.  Many government agencies, including the Department of Fisheries, are now using GDA94.

This allows users to accurately determine their location (latitude, longitude and altitude) anywhere on the planet, regardless of weather or light conditions.

In January 2000 the rollout of GDA94 chart datum began, replacing the older AGD66 or AGD84 data.

The new standard is more accurate and universal, so GPS users need to ensure that their GPS settings are correct by using GDA94.

Do I need to change my GPS settings?

It is important to change your GPS if it is currently set to AGD66 or AGD84. A change to GDA 94 from AGD 66 or AGD84will show as a shift in the position of waypoints (approximately 200 metres in both Easting/Northing and latitude/longitude). This apparent change will vary according to the map scale.

If your GPS is set to WGS84, it is not essential to change your GPS settings, as GDA94 coordinates can be considered the same as WGS84. If you choose to change (from WGS84 to GDA94), then your waypoints will not be noticeably affected.

How do I change my settings?

GPS units can be easily changed to GDA94 chart datum by selecting the appropriate setting within the unit's menu options.

If coordinates of waypoints have been taken from maps that are in datum AGD66 or AGD84, then an offset (adjustment) will be required. If coordinates of waypoints have been taken from maps that are in datum WGS 84 or GDA 94 then no offset is necessary. 

People should contact the relevant equipment manufacturer if they experience any difficulties with changing their GPS unit to the new chart datum.

Be safe - update

The Department of Fisheries recommends that all fishers and boat users update their maps and charts so they also comply with the newer chart datum.

For safe navigation, boat users are encouraged to use GDA94 as it matches the latest navigation chart datum.

By using GDA94, you will also minimise or eliminate the risk of inadvertently fishing or boating within marine parks and sanctuary zones.

There have been cases in which Fisheries and Marine Officers have found boat users and fishers in breach of marine park and sanctuary zone restrictions, simply because they were using outdated GPS coordinates (chart datum). Incursions into marine parks or sanctuary zones can carry penalties of up to $10,000.

Contact your local Department of Fisheries office for more information on GPS and chart data.

More information can be found online at http://www.icsm.gov.au/gda/faq.html#what