WXTides Stations (Lots) in OpenCPN

[Ptizef]

Originally Posted by Netsurfer

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

Has I sayed , data are coming from various sources , mainly wXtide and French documents

Originally Posted by Netsurfer

I didn't check this yet.
But there is already one big disadvantage. When using your files the reference station is missing.
Gunther

For which secondary station , the reference station is missing ? could you give me an example ?
Normally , if there is no reference station displayed ,that means that the station is a reference one

Originally Posted by Netsurfer

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.
Gunther

Yes for me too ; That's why I started to do these files

Originally Posted by Netsurfer

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

I did many controls but other users controls and opinion would be welcome

Originally Posted by Netsurfer

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

May be you should post this request at the right place :
SourceForge.net: OpenCPN: Tracker


Jean Pierre

[idpnd]

Just to clarify, your harmonics file contains the wxtides worldwide data with a few corrections? Should we publish this on the opencpn wiki?

[Ptizef]

Originally Posted by idpnd

Just to clarify, your harmonics file contains the wxtides worldwide data with a few corrections?

yes but I would say ....with many corrections

Originally Posted by idpnd

Should we publish this on the opencpn wiki?

Yes of course

Jean Pierre

[Netsurfer]

Hi,

Originally Posted by idpnd

Just to clarify, your harmonics file contains the wxtides worldwide data with a few corrections?

Attention!
It does contain only data for West Europe (Norway down the North Sea, Atlantic, including Azores, Canarias)

Should we publish this on the opencpn wiki?

For many european sailors this data will be totaly enough, because they don't need all the American tidal stations at all.

So it might be a possibility to offer different sets of harmonic files (by region).
Anyone can download the needed/preferred one.

Installation is quite simple. All you have to do is to copy the 2 files in the TCDATA directory of your OCPN installation.

Gunther

[idpnd]

Where do you copy the harmonics file in linux?

[Netsurfer]

Hi Jean Pierre!

Originally Posted by Ptizef

Has I sayed , data are coming from various sources , mainly wXtide and French documents

Yes, I read this.
But for use with (w)xtide you need some kind of "special" data and couldn't find any source for such data yet.

For which secondary station , the reference station is missing ? could you give me an example ?
Normally , if there is no reference station displayed ,that means that the station is a reference one

OK, here they are (only Portugal from N to S)

• Viana do Castello
• Leixos (Porto)
• Aveiro
• Figuera da Foz
• Peniche
• Cascais
• Sesimbra
• Sines
• Lagos
• Faro-Olhao
• Vila Real De Santo Antonio

All these stations do not show up the reference station (which has to be Lisbon in all cases).

May be you should post this request at the right place :
SourceForge.net: OpenCPN: Tracker

Yes, I know - thanks.
You can see my posts there (Netsurfer24)

Gunther

[Ptizef]

Hi Gunther

Originally Posted by Netsurfer

But for use with (w)xtide you need some kind of "special" data and couldn't find any source for such data yet.
Gunther

To calculate and display tides , opencpn need :
For references stations :
- position lat/long , meridian , name (in file Harmonic.idx)
- name, unit,meridian,harmonic constants (in file Harmonic)
For secondary stations :
- position lat/long , meridian , name
,offset time/height , name of the reference station (in file Harmonic.idx)

Of course , the difficulty is to find harmonic constants for reference S and offset for secondary S . These data are not available from European national offices as it is in the US .
wXtide files are usable as they are and contain these data , but for France , Spain Portugal , there are very few reference stations and with many incoherences between data (offset multiplied by three etc ..) . So I have corrected some data , created new reference stations with constants coming from various sources : old French documents , other free software etc.. .Lot of these data were entered manually

Originally Posted by Netsurfer

OK, here they are (only Portugal from N to S)

• Viana do Castello
• Leixos (Porto)
• Aveiro
• Figuera da Foz
• Peniche
• Cascais
• Sesimbra
• Sines
• Lagos
• Faro-Olhao
• Vila Real De Santo Antonio

All these stations do not show up the reference station (which has to be Lisbon in all cases).
Gunther

These stations are all reference ones. This is a part of the data I added ( the stations I have created are written in capital letters )

Originally Posted by Netsurfer

Yes, I know - thanks.
You can see my posts there (Netsurfer24)
Gunther

Sorry , I read your posts

Originally Posted by Netsurfer

So it might be a possibility to offer different sets of harmonic files (by region).
Anyone can download the needed/preferred one.
Gunther

I agree , it would be a very good solution to offer different set of files

Regards

Jean Pierre

[idpnd]

Sounds like you put a lot of effort into this Jean-P, why different sets? I think there should be a best breed one. Distribution of this data probably involves some difficult legal questions sadly.. The xtides guy got pestered to take off certain data after a while, hence the vastly reduced set of data vis-à-vis wxtides..

[hackoon]

What about to implement an import tide and current data option? So every user could import from whatever sources they prefer. It would solve legal questions or at least shift them to each user. It would also solve performance problems (tide and data make opencpn terrible slow on my machine at least).
Well it would of course need some form of database management (see discussion of sqlite).

[Ptizef]

Hi IDPND
I do not understand any thing about legal problems but I suppose it's very complex
Data are coming from and was the property of national offices and in the past were freely available . Now these offices have decided to no longer distribute it .So all data which can be found are old data . So who except the notional offices could claim about property ? I don't know .
Anyway , my point was only to create a data base for my personal use ,but , as it is created , I thought it was better to allow other opencpn users to use it if they want . So I agree to all better solution to make it available .
Regards
Jean Pierre

[idpnd]

Don't get me wrong, I'd be the last person stopping you The safest option for the project is probably to distribute the safe data as supplied with xtides, if we decide to implement data on a personal basis that's up to us.. The procedure for importing customised harmonics files and should be documented on the wiki, don't think a separate feature is worthwhile.. Most users (US) get full data anyhow..

The coverage of other countries suffered a major blow in 2001...

Some further reading News

[hackoon]

Originally Posted by idpnd

don't think a separate feature is worthwhile.. Most users (US) get full data anyhow..

Well I suggest we change the name to US-CPN if the rest of the world doesn't matter that much...

[Netsurfer]

Originally Posted by hackoon

Well I suggest we change the name to US-CPN if the rest of the world doesn't matter that much...

That's sometimes the problem that some people believe the rest of the world doesn't matter ...

Originally Posted by idpnd

Distribution of this data probably involves some difficult legal questions sadly.. The xtides guy got pestered to take off certain data after a while, hence the vastly reduced set of data vis-à-vis wxtides..

AFAIK couldn't you change the license retroactively, which means if the data were once available for free (use), then you can use it forever. And the affected data won't (significantly) change over the years. And who will prove, from which source the data has come?
So it looks like a relative small problem to me, but ...

Originally Posted by hackoon

What about to implement an import tide and current data option? So every user could import from whatever sources they prefer. It would solve legal questions or at least shift them to each user. It would also solve performance problems (tide and data make opencpn terrible slow on my machine at least).
Well it would of course need some form of database management (see discussion of sqlite).

... that sounds like a good idea to me!
Based on the actual state/ handling maybe the easiest way of implementing is to make OCPN recognize subdirectories of TCDATA and make them selectable via a drop-down list. So one could install as many harmonic files as desired and easily choose which one to display (only one set at a time).

Originally Posted by idpnd

Don't get me wrong, I'd be the last person stopping you The safest option for the project is probably to distribute the safe data as supplied with xtides, if we decide to implement data on a personal basis that's up to us.. The procedure for importing customised harmonics files and should be documented on the wiki, don't think a separate feature is worthwhile.. Most users (US) get full data anyhow..

Regional versions of harmonic files could be offered for download or linked in the localized versions of the wiki.

Gunther

[Ptizef]

Hi ,
You can find a new version of harmonic files for Western Europe .
The changes are :
-More constants for reference stations (that means better accuracy ) Many thanks to SailorF54 for providing the data
-La Carraca , Cadiz , Rota , Pasajes (Spain) and Antifer (France) are now reference stations
Regards
Jean Pierre

[idpnd]

Sounds great, will give it a go..

Oddly enough, the reference stations are not cited in the new additions, but they are still cited for the older entries?