Track Logs

Track logs are lists of waypoints that were automatically recorded either by a GPS or by a computer connected to a GPS such as can be done using the Nobeltec program.They are a history of where a boat has actually gone as compared to a route which is someone's choice of where he'd like to go. I use them to get waypoints for building routes. By that I mean that I display the tracklog waypoints as a route in some program and then select those where I want to go. For example you could import a track log as a route into CAPN, display the route, change its color (to allow seeing the new route) and then create a new route over the top of the track log waypoints.

For areas of the world that are well charted, this isn't too useful, but for areas like the Western Caribbean where the charts are poor you need to get waypoints from some where for reef passes etc. Tracklogs are a good source.

Rio Dulce gorge Guatemala

The following files are tracklogs that I saved from my ICOM GP-270ML gps from the trip I took from Florida to the Bay Islands of Honduras thru Mexico, Belize and the Rio Dulce. The waypoint data is in the format for my GPSDevComm program which can write the waypoints to NMEA(for CAPN), Nobeltec and MaxSea formats. Each waypoint has the date/time it was saved as its description. See below to download a copy of the GPSDevComm program.

I have loaded these tracklogs into a Navigation program, took screen prints, captured the images and posted them at Tracklog Photos on the IslandPacket Photo site.

Culebrita Spanish Virgins

The following files are the tracklogs for a trip from Florida to Trinidad. There are two gaps in the tracklog that occured when my GPS's internal battery went dead. The first is from Antiqua to Iles de Saintes and the second from St. Pierre, Martinique to Marin, Martinique.

All of the following files are in this zip file.

Schooner at Tobago Keys

We cruised in the same area as last season (Trinidad to Antiqua and back) only going to one new area: Antiqua and Barbuda. These were very nice. The anchorages on northern Antigua and southern Barbuda were hardly occupied and had very nice snorkeling.

Here is the tracklog for Antiqua and Barbuda. My GPS was having problems, and I lost the data for some of the legs. For example from Great Bird Island back to Jolly Harbor.

The GPSDevComm program is downloadable from a zip file. See the Readme.txt file inside the zip for installation instructions.

Accuracy of waypoints

The Track log accuracy for waypoints on my ICOM GPS is controlled by the Limit Max Track Error. This is defined such that "the recorded track points connected with straight lines will always be within the error tolerance of the actual track of the boat." It was set to 0.05 nm for most of the tracks. I occasionally set the limit to a lower value for some passes when I thought of it. A setting of 0.01 saved a lot of waypoints.

 

If you have any comments or good advice, write me at: radder@hotmail.com.