WXTides Stations (Lots) in OpenCPN

[idpnd]

Hackoon has posted the following at sourceforge, I thought you may find this of interest:

2010-01-09 11:51:17 GMT I uploaded the file, it is joined from wxtide and opencpn. As wxtide is GNU this should be free as well. I hope you integrate it in openwrt. The joining was a quickhack and I had to fill a lot of zeros in to make it campatible with the new format of harmonic files -> PLEASE DO NOT RELY ON IT.
http://fserv.skill-club.com/get_1088_156a.html

This did work for me, copy files to /usr/local/share/opencpn/tcdata on Linux, but note that these stations are most probably less reliable than the xtide fare (they have actually just dropped a number of German stations for being unreliable!).

Perhaps you could test these stations against official/current tidal data you may have at your disposal/find online.

[idpnd]

Hm just tested it, for Scarborough (Tobago) it uses Panama as a reference station and gets it totally wrong.. Ooooops..

[Netsurfer]

Hi everybody!

I'm a new user to OpenCPN.
Because we want to use the program for navigation at the Portuguese coast this year, I'm also very interested in getting the tide informations in OpenCPN.

I tried the above files and it worked so far.

But I'm still concerned about the quality of the data.
Therefor I searched for some other data to compare/ check them.

One place I found e.g. is: http://www.mobilegeographics.com:81/...=2010&m=12&d=1

BTW: If you use Thunderbird (with the Lightning Add-on) for Windows, you can downlaod the data as 'ics' file to your calendar (and use a different calendar for each location).

Another interesting source seems to be: XTide Downloads

The archive 'harmonics-dwf-20091227-nonfree.tar.bz2' contains a 'tcd' file (which is very actual compared to the other sources).

Now my question: Can anyone give me a short description on how to get a tcd-file work as database for the tidal information in OpenCPN, please?

Alternatively there ist also an txt-file available. But just exchange (after renaming it) it with the existing HARMONIC file in 'TCDATA' doesn't work. The tidal locations are present, but with no tidal data/ information.

Any help would be appreciated - thanks!

Greetings
Gunther

PS: I'm using OpenCPN on Windows (XP + 7) 32Bit

[idpnd]

If you check on the list at the wxtides, I don't think any Portuguese locations are included there at all Tidal data is highly restricted, and xtides only includes the most current, legal and verified data (and actually purged lots again for their most recent data set).

However, the site you link to seems to be using this data, which is just as extensive as the wxtides set..

How did the wxtides data size up btw? You didn't mention the outcome of your comparison.

[idpnd]

I've just had a look around myself, most stations seem to compare quite favourably with both the mobilegraphics site and the official UK govt "easytides" service. Sites checked: Oostende, Lisboa, Ilha do Brigue (Amazon). They first two seemed to be about 30 minutes off, the latter was spot on.

See attached screenshot for a sample.

[Netsurfer]

Hi,

Originally Posted by idpnd

If you check on the list, I don't think any Portuguese locations are included there at all Tidal data is highly restricted, and xtides only includes the most current, legal and verified data (and actually purged lots again for their most recent data set).

You are right.
I imported the new TCD file into PolarView (Polar Navy) which offers therefor an easy import function (=> feature request for OCPN ). And yes, there aren't any Stations around France, Spain and Portugal.

How did the wxtides data size up? You didn't mention the outcome of your comparison.

Well, I am not quite sure yet.

After some Googling I found out that you can get the official tidal data from the Portoguese Hydrografical Institute by mail (for 13 different places on the continent, each for a quarter of the year).
See: Instituto Hidrográfico (no ENglish version - only Portuguese, but quite guessable)

So I'm still not quite sure about the time basis/ zone in WXTide. Under some circumstances the data seems still quite usable (differences of up to 5-10 minutes doesn't matter).

Though every place along the cost of Northern Spain and Portugal is referenced to Lisbon, it would be a nice option, if the time difference for each location would also been shown in the tidal window of OCPN. So it would be a lot easier to compare the time-tables.

I'm aware of the fact, that things like GRIB and Tides & Currents are only secondary theatre (aside the chart display and navigation), but they would also be 'nice to have' features.

And I would also like to help getting the program one step further, but unfortunately I'm not a programmer (more or less some kind of Webdesigner).

Gunther

PS: BTW I'm still interested in how to make the HARMONIC files (for use with OCPN) out of a TCD file?

[idpnd]

Hackoon prepared the original file, you may wish to query him on the sourceforge thread about this issue..

The reference station is cited in opencpn btw.

Also see my comparisons with UK govt easytides service above if you wish to investigate further..

[Netsurfer]

Originally Posted by idpnd

Hackoon prepared the original file, you may wish to query him on the sourceforge thread about this issue..

Yes, I'll do this.

The reference station is cited in opencpn btw.

Yes. But the time difference for HW and LW to the reference station is missing (=> feature request).
BTW: The font-size is a bit too large (espacially if there is more than one line of text) and the alignment is slipped to the right. But as far as I see the window is not resizeable

Also see my comparisons with UK govt easytides service above if you wish to investigate further..

Yes, thanks.
I gave it alreday a first visit, when I saw your screenshot ...!

[zemaria]

The files HARMONIC are original from xTide and then used by a WINDOWS Port WxTide32 now in version 4.7. They have almost all the world ports, but in 2001 the U.K. Hydrographic Office claimed legal rights on most of the data, and the developers were obligated to remove that data. So in 2002 all that was left was the US data. With some major Ports in the World. After that another data has been added.

In some old HARMONICS files there are 1 hour difference to the Portuguese Ports, because of the change in the portuguese legal Timezone.
This can be changed in the HARMONICS.IDX file for each Port.
ORIGINAL
TEur:Porg:: -8.8333 41.6833 1:0 Viana do Castelo, Portugal
CHANGED
TEur:Porg:: -8.8333 41.6833 0:0 Viana do Castelo, Portugal

[Netsurfer]

Hi,

thanks for the information!
Step by step I'll understand the underlieing 'system'.

Here are the results for todays date (03.02.2010) for Lisbon, Portugal:

WXTide 32:

Lisbon, Portugal
Units are meters

Wednesday 2010-02-03   
Sunrise  8:40 AM M, Sunset  7:00 PM M
Moonset 10:46 AM M, Moonrise 12:28 AM M
   Low Tide:  12:07 AM M   0.5
  High Tide:   6:51 AM M   4.0
   Low Tide:  12:38 PM M   0.6
  High Tide:   7:16 PM M   3.7

EasyTide (EasyTide - on-line tidal predictions from the UKHO):

HW     LW    HW    LW
05:57 11:40 18:20 23:54
4.1m  0.6 m 3.7 m 0.8 m

The Portuguese Hydrografical Institute:

6   4      3.9
11 55       .4
18 27      3.6

and the winner is ...

The WXTide data is from a stand-alone version where there is still the 1:00 hour difference in the idx file as you described in your answer.

As I already wrote - some minutes difference doesn't matter.
So it seems, that the WXTide data is also usable.

In the updated harmonic.idx file linked in this thread here, all Portuguese stations are correctly with 0:00.

Still need to take a look at the Spanish stations which also refer to Lisbon but having +1:00 hour against UTC.

And do you if WXTide is calculating summertime?
Because if I had a look at the 28th March 2010 (that's when summertime starts) there is a jump of nearly 2 hours in the results.

Gunther

[hackoon]

the whole voodoo about the conversion from wxtides "harm_msc" to opencpn's "HARMONIC.IDX" is to fill the missing fields with "x 0 0"

[Ptizef]

Hi,
You can try to use these files . They have been updated from various sources and are limited to western Europe . (Normally the problem of time offset for Portugal and Spain is fixed) .
If you test some stations , please let me know the result
Jean Pierre

[idpnd]

Hi Jean Pierre,

I am currently using hackoons world wide set (see my link above) as derived from wxtides.. have you tried that?

[Ptizef]

Yes of course .
The two files I proposed are from wXtide too but with many changes mainly for Portugal , Spain , France , for where I created more reference stations . Globally I thing that the results are a little bit better than wXtide for this region
Jean Pierre

[Netsurfer]

Hi Jean Pierre!

Originally Posted by Ptizef

The two files I proposed are from wXtide too but with many changes mainly for Portugal , Spain , France , for where I created more reference stations .

How have you done this?
Where did you get the needed data from?

Globally I thing that the results are a little bit better than wXtide for this region

I didn't check this yet.
But there is already one big disadvantage. When using your files the reference station is missing.
As I wrote further up in this thread, I'm espacially interested in data for Portugal. And AFAIK ist every station along the Portuguese coast and even at the Spanish coast all the way up to the French boarder referenced to Lisbon.

And due to getting the actual official tide table from the Hy-Office, you could easily compare the results.

BTW: @programmer, please improve the tidal window in OCPN by

• also displaying the time differences to the reference station
• not only showing the curve but also the exact time values for HW and LW

I think, I add this as a feature request on SF, too.

Gunther