I'd like to analyze GPS data with some sort of software helping to learn
something about my regattas.
I've found just GarTrack. It's very very simple and most of all accept just
a strange file format (gardown)
The results is that I cannot get neither convert (many hours spent on
Internet) my data to something GarTrack could be feeded with.

Do you know something better than GarTrack that, also, can accept a more
widely available file format?

Thanks for helping.
Alberto.-

On Thu, 20 Jan 2005 23:26:21 GMT, "Alberto \(Tilax\)"
wrote:

I'd like to analyze GPS data with some sort of software helping to learn
something about my regattas.

=====================================

I assume you are talking about a sailing regatta? If so you really
need more than GPS data for a comprehensive analysis. I'd also want
wind speed, wind angle, boat heading and boat speed through the water
just for starters. All of that can be logged out and replayed using
some of the more sophisticated instrumentation systems, and you can
use it to cerate your own polar diagrams, target speed charts, etc.

That said, if you really just want GPS data, Maptech Offshore
Navigator does a good job with track logs. You'll have to do the
analysis yourself however.

http://www.maptech.com/water/Offshor...ator/index.cfm

"Wayne.B" wrote

wind speed, wind angle, boat heading and boat speed through the water

Did you mean "speed over the ground:"?

Not sure how it helps to know a measured-log calculation of 10kts when the
tide and current might be holding you to 5kts over the ground ;-) If you
know your boat's hull speed under various sails and points off the wind you
could estimate current from speed (vector) over the ground, but not the
other way around given only speed through the water, which would include an
unknown vector of current direction.

Jack

On Thu, 20 Jan 2005 23:26:21 GMT, "Alberto \(Tilax\)"
wrote:

I'd like to analyze GPS data with some sort of software helping to learn
something about my regattas.
I've found just GarTrack. It's very very simple and most of all accept just
a strange file format (gardown)
The results is that I cannot get neither convert (many hours spent on
Internet) my data to something GarTrack could be feeded with.

Do you know something better than GarTrack that, also, can accept a more
widely available file format?

Thanks for helping.
Alberto.-


Much will depend upon the exact file format that you have. You could
try "GPS Utility" and the Import File Converter that is available on
www.gpsu.co.uk. The Import File Converter is designed for dealing
with large varieties of text format files (e.g. *.csv) and converting
them for use in GPSU.

I hope that helps.
Alan Murphy (author GPSU)

On Thu, 20 Jan 2005 21:11:20 -0500, Wayne.B
wrote:

I assume you are talking about a sailing regatta? If so you really
need more than GPS data for a comprehensive analysis. I'd also want
wind speed, wind angle, boat heading and boat speed through the water
just for starters. All of that can be logged out and replayed using
some of the more sophisticated instrumentation systems, and you can
use it to cerate your own polar diagrams, target speed charts, etc.

And if you don't have one of those sophisticated instrument systems,
my cpRepeater program exports all that and more in a simple table
easily read into a spreadsheet or database. That's the simple part.
The fun part is the analysis.
__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at world wide wiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/

On Fri, 21 Jan 2005 01:40:47 -0500, "Jack Painter"
wrote:

Did you mean "speed over the ground:"?

=====================================

No. When you are evaluating sailing performance you are usually
concerned with "Velocity", i.e., speed through the water. Obviously
SOG is important from a strategic and tactical viewpoint but sail
trim, sail selection and helming are first viewed with respect to
speed.

I assume you are talking about a sailing regatta?

Yes

If so you really
need more than GPS data for a comprehensive analysis. I'd also want
wind speed, wind angle, boat heading and boat speed through the water
just for starters. All of that can be logged out and replayed using
some of the more sophisticated instrumentation systems, and you can
use it to cerate your own polar diagrams, target speed charts, etc.

Obviously you're right.
It's just a money issue.
I'm taking a step at a time: GPS first, relative wind as a second step

That said, if you really just want GPS data, Maptech Offshore
Navigator does a good job with track logs. You'll have to do the
analysis yourself however.

Hope it would not be the usual tracking SW. There are alot not so useful for
the deal.
GarTrack (even if I don't like it) could import GPS data (just if I could
have the right file format) and then it let me enter wind data manually.
So not a great thing but I could be enough as a fice step

www.gpsu.co.uk.

Already tried.
I can convert almost anything but what I need :-(

Alberto.-

Did you mean "speed over the ground:"?

I confirm what Wayne sais.
I'm interested in speed against water... the only thing helps in trimming
the boat.

Alberto.-

"Wayne.B" wrote in message
...
On Fri, 21 Jan 2005 01:40:47 -0500, "Jack Painter"
wrote:

Did you mean "speed over the ground:"?

=====================================

No. When you are evaluating sailing performance you are usually
concerned with "Velocity", i.e., speed through the water. Obviously
SOG is important from a strategic and tactical viewpoint but sail
trim, sail selection and helming are first viewed with respect to
speed.


Understand wrt sail trim, and those are the known characteristics of a boat
that I referred to. When I raced in the Great Lakes, speed through the water
was a good evaluator of trim. Not enough information in the Chesapeake Bay
though, when currents are a major factor.

Velocity = speed + direction. To evaluate the effectiveness of a course to
mark, speed through the water is not relevant, and SOG from a GPS is still
only part of the equation, it requires an additional computer calculation to
determine effective VOG, that is; Course Made Good + SOG.

On a visual bearing to the next mark as a lay line, within a minute of
averaging time, most computers will settle at a reliable Course Made Good,
which is velocity over ground adjusted for the effect of currents and slip.
This also allows a calculation of time to mark. SOG however is instantly
available (a few seconds delay at most) and is more relevant to verifying
the known performance standards of sails, trim, degrees off the wind and
speeds that result from this. If current is dragging you to weather for
instance, then more heel (allowing more slip) could maintain best speed over
the best course to the mark. Historical GPS tracks around a course do not
tell the story it took to get there. Neither could speed through the water
by itself help trim the boat for best course to a mark that you won't
achieve without more information.

Jack, who was a Gary Jobson fan for about 25 years.