[AugustH]

There are a couple of functions I'm thinking of adding to Mr. Tides in the 3.1 release (which I've not even started on, so don't get all excited). There have been many requests for a way to add stations, and I can see how to do this for subordinate stations (though it will require some changes to the XTIDE database engine). I can't really see how to add reference stations, the harmonic constants are too many to just guess at, and the only ones who have enough data to create them usually are very reluctant to give them away for free (read: England).

The other idea is Collections of stations that all open together. So if you're planning a trip, you can beforehand make a collection and see them all at once as you sail along.

Maybe I'll add closer integration with MacENC and GPSNavX, pulling GPS data from them to display on the map. I'm not sure on this one, it just came to me.

As more ideas come to me (or you, the reader, make suggestions [hint hint]) I'll update this post with my progress.

August

[ReeferJon]

Please, please, please... Tidal Vectors in MacENC!!!!

I realise that this may be more of a point for GPSNavX than yourself, August, but to have direction of flow and strength at a specific time would be invaluable for passage planning.

I actually purchased Belfield's Tidal Plotter for Windows, just so that I can get tidal flows in the Solent where I sail (it's a fairly complex tidal zone) but I still use Mr Tides within MacENC for checking tides "on the move".

Here's a screenshot of the tidal vector functionality.



Don't get me wrong.. Mr Tides is a great application.. but this is the one area that's missing in Mac Marine Software.

[cyberhusky]

Please, please, please... Tidal Vectors in MacENC!!!!

I realise that this may be more of a point for GPSNavX than yourself, August, but to have direction of flow and strength at a specific time would be invaluable for passage planning.

I'm waiting for this too...

with some infos like MaxSea does

http://comen.maxsea.fr/MaxSea/Products/F...fault.aspx

or precalculated passing route which takes into account tides and tidal streams, as shown here:



Manou

[AugustH]

NOAA explicitly warns against interpolating currents between stations:

• Currents are spatially variable, thus predictions should NOT be extrapolated even to nearby locations. Interpolation between two nearby locations should NOT be attempted. Use of such extrapolations can be hazardous.(emphasis is theirs)[/list:u]
  
  Unless there is a flow model available that describes mathematically how the currents vary over time, it's impossible to take isolated stations and create a chart that accurately reflects the currents. The programs listed in the other posts must use very simple models, or the areas they cover are simple enough (not changing that dynamically over time) that they can form predictions based upon limited data. This is my speculation, though, as I have not looked at them.
  
  For example, up here in the San Juan Islands the currents are incredibly complex. The Canadian Fisheries service produced a book with about 90 separate images of what the currents do, based upon the tide height at a station and how long ago the high tide occurred. The images show currents that reverse flow in a short space, flows that spiral, and flows that change velocity dramatically over one hour. Modeling something like this requires hours of computer time, not something that we simple users can do.
  
  Look at this example and you can see why current vectors are something neither Richard nor I want to even get close to:
  
  

[ReeferJon]

I do take your point about interpolation not being as accurate as the properly modelled tidal charts available from the official HOs. However the fact remains that a significant number of PC-based marine charting applications are able to provide tidal vectors. This means that..

(a) they're using a dataset similar to Mr Tides and interpolating it or

(b) they're plotting vectors from more detailed data than is available in the Xtide harmonics database.
Some cartography (certainly Maptech's BSB charts, and I believe some S57 charts) include additional information about the tidal vectors in the area that they cover.

So maybe this is a question that needs to be addressed by the charting software...

[AugustH]

Or they are ignoring the NOAA warnings and interpolating between stations.

The commercial people do have access to harmonics that the XTIDE-based people (me!) don't have. That's been proven in England and Australia, and I suspect many other places aren't releasing new harmonics but I can't show this. So I don't find it hard to believe that the commercial programs can get current flow models from government agencies after providing some lucre.

Another suspicion I have is that the particular locations that have flows are simpler to model than the San Juan's. I'd have to compare their output for a long period of time with what Mr. Tides produces, and see if there's some correlation. But even after doing that I'd still have reservations about the accuracy of the model I'd come up with, and I don't know what resolution I'd use. The two pictures I've seen on this thread are fairly broad overviews, and I don't know how far down you can go to get detailed flows.

Very interesting thread!

[cyberhusky]

The commercial people do have access to harmonics that the XTIDE-based people (me!) don't have. That's been proven in England and Australia, and I suspect many other places aren't releasing new harmonics but I can't show this. So I don't find it hard to believe that the commercial programs can get current flow models from government agencies after providing some lucre.

If commercial marine software vendors get access to harmonics from government agencies, wouldn't it be easier for Rich to get access too? Probably it isn't so expensive to get the data, and I would be willing to pay more for Mac Navigational Software if i included reliable tides and currents info.
On the other hand it could be that the data isn't just available to the public because of security issues, that is government don't trust free software? (Which is a shame because most genius applications are from the shareware/free market: Open-Office, Linux etc.)

Though this is just an idea.

Manou

[GPSNavX]

MacENC does plot any tidal currents/streams that do exist in the S-57 data. Such tidal/streams are going to be average maximums.

There was further disucssion on using currents for routing in the 'Show optimal tacking routes' thread in the GPSNavX/MacENC forum.

So far MacENC has avoided interpolation of data (i.e. GRIB forecasts including current) because such linear assumptions will certainly lead to significant error.

[JoMeKe]

such linear assumptions will certainly lead to significant error.

...and the related liability. Though I too would love to see detailed current vectors overlaid on an electronic chart, I certainly understand the inclination to "not go there". It's one thing for a government agency to print that info, but a small software outfit with limited pocket depth is a different story.

[Coomkeen]

Maybe I'm missing something here, but computers and software and data limitations aside, if we are not supposed to interpolate between stations, what does your average bloke do actually on the sea with a paper chart?

Ron

[cyberhusky]

Maybe I'm missing something here, but computers and software and data limitations aside, if we are not supposed to interpolate between stations, what does your average bloke do actually on the sea with a paper chart?

Ron

That's what came too my mind too. It's true that tides/current almanachs show tides data for a set of hours (1,2,3 o'clock etc.) but you have to interpolate the time between these charts.

I think having a map showing tides/current arrows just gives an indication what to expect. This would simplify planning your trip, though you still have to check almanachs with tides and currents tables/charts.
The same goes for papercharts! I would never leave habour without them! Even if I have my iBook running and showing my position: I still refer to papercharts just in case.

Manou

[JoMeKe]

Maybe I'm missing something here, but computers and software and data limitations aside, if we are not supposed to interpolate between stations, what does your average bloke do actually on the sea with a paper chart?

Ron

That's what came too my mind too. It's true that tides/current almanachs show tides data for a set of hours (1,2,3 o'clock etc.) but you have to interpolate the time between these charts.

I think that hits on it. YOU are doing the interpolating. If you're wrong, you can sue yourself. Sorry state of affairs, particularly here in the litigious US, but so it is.

[fish2live]

I've just returned from several months of fishing in the central Aleutians where the currents are at least as bad as in the San Juans. I find it odd that you would worry so much about NOAA warnings on interpolation. The published current tables for the Aleutians aren't based on interpolation; rather, they are based on extrapolation from the few accurately measured stations in the eastern Aleutians. If NOAA extrapolates its own tables then a bit of interpolation can't be so bad.

Your discussion sort of misses the point that in many cases, anything is better than nothing at all. Most commercial fishing boats run Windows nav packages that do include current vectors in their displays. Nobody sees them as the gospel truth, but they do add a visual reminder of somebody's initial estimate of the situation. Despite the inherent inaccuracy I think the lack of current vectors is my biggest point of envy with the Windows packages.

Current vectors will never be perfect, and that is no reason to shy away from them. In the end they're not so different from weather forecasts. Ideally some easy way would be provided to alter the slack times and peak current speeds for individual arrow symbols so that familiarity with an area would eventually lead to reasonable accuracy. Maybe current vectors should be presented as a personal mapping tool rather than a statement of conditions. I'd really like to be able to make my own.

[Eclipsemullet]

What about Mr Tides for iPhone & iPod Touch. Safari-based, I guess.

[Patrick]

Hi Folks

I've been enjoying this topic a lot as it's near and dear to my heart. I enjoy a sport called Predicted Log Racing, also known as Cruiser Navigational Contests. Tidal currents are its life blood and knowing what they will be means the difference between winning or losing. I've been log racing since 1986 and I've used every piece of tidal current information there is, you name it I've used it. It's my opinion that as for predicted speed and time of that speed it's a crap shoot. I call it guesstimating. However the direction arrows or what ever the information uses to show direction is pretty close to true. So what ever program you use, take the speed stated with a grain of salt, but it's direction stated will be in most cases pretty good. Just my opinion for what its forth. To learn more about Predicted Log Racing check out this web site; http://www.ipbalogracing.org/default.htm

[cyberhusky]

What about Mr Tides for iPhone & iPod Touch. Safari-based, I guess.

Mr. Tides exists as Widget for OS X. So programming it for the iPhone/iPod Touch should be no problem. At least I think so.

http://osx.iusethis.com/app/tidewidget

[cyberhusky]

Hi Folks

However the direction arrows or what ever the information uses to show direction is pretty close to true. So what ever program you use, take the speed stated with a grain of salt, but it's direction stated will be in most cases pretty good.

Direction informations would be enough for my use even if the speed isn't accurate.

We already have the same info for wind directions with GRIB files and weather infos in GPSNAVX.

Regards
Manou

[Eclipsemullet]

Mr. Tides exists as Widget for OS X. So programming it for the iPhone/iPod Touch should be no problem. At least I think so.

OFFICIAL: Third-party apps coming to iPhone

"Let me just say it: We want native third party applications on the iPhone, and we plan to have an SDK in developers’ hands in February. We are excited about creating a vibrant third party developer community around the iPhone and enabling hundreds of new applications for our users. With our revolutionary multi-touch interface, powerful hardware and advanced software architecture, we believe we have created the best mobile platform ever for developers.

It will take until February to release an SDK because we’re trying to do two diametrically opposed things at once—provide an advanced and open platform to developers while at the same time protect iPhone users from viruses, malware, privacy attacks, etc. This is no easy task. Some claim that viruses and malware are not a problem on mobile phones—this is simply not true. There have been serious viruses on other mobile phones already, including some that silently spread from phone to phone over the cell network. As our phones become more powerful, these malicious programs will become more dangerous. And since the iPhone is the most advanced phone ever, it will be a highly visible target.

Some companies are already taking action. Nokia, for example, is not allowing any applications to be loaded onto some of their newest phones unless they have a digital signature that can be traced back to a known developer. While this makes such a phone less than “totally open,” we believe it is a step in the right direction. We are working on an advanced system which will offer developers broad access to natively program the iPhone’s amazing software platform while at the same time protecting users from malicious programs.

We think a few months of patience now will be rewarded by many years of great third party applications running on safe and reliable iPhones.

Steve

P.S.: The SDK will also allow developers to create applications for iPod touch. [Oct 17, 2007]"

[AugustH]

Thanks to everyone who's posted! Based upon what you've said, I'm working on a way for Mr. Tides to generate a list of current stations in an area that will give the value and direction of the current (based upon whether it's an ebb or a flood and what NOAA says the direction is) and export that information via AppleScript. This will let other programs query Mr. Tides for the vectors and display them. I might include current arrows on my maps if I can figure a way to do that too, but I want to stay focused on tides and not navigation.

As for the Tide Widget, I'm going to work on an update for Leopard that will look pretty good (a mockup by another person is really sweet!) and hopefully get that out soon.

As far as the iPhone, as soon as the SDK is out I'll start working on something. It'll be based upon the widget, if that's possible. I'll know more when I actually get the SDK.

August

[cyberhusky]

Hi August,

Wow great ideas! That's what I wanted to hear!
So we will see tides arrows in MacENC then? Please, please! Mr. Ray ;-)

Keep up the great work.

BTW where can I donate for Mr.Tides?

Regards,

Manou

[AugustH]

I have a button on my web site to donate via Paypal. The web site is at http://web.mac.com/augusth/Tides3/Home.html and then scroll down to the bottom to get to the button.

August

[ReeferJon]

Hi August - Great News!
That sounds excellent. I'd be delighted to help Beta the UK tidal flows when you're at that stage.

[Eclipsemullet]

Any news re. this?

[AugustH]

It's coming along. I've implemented an applescript event that returns current stations with their name, location, value, and direction as defined by the data files. It's still in testing and needs some work, though. When it's ready I'll let Richard know, and he can play around with it.

[AugustH]

Oh, and as far as the iPhone, I've not seen the SDK so I have no idea. That'll have to wait until next year before I can even consider it.