Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rating: Thread Rating: 4 votes, 5.00 average. Display Modes
Old 29-09-2009, 07:30   #76
Marine Service Provider
 
bdbcat's Avatar

Join Date: Mar 2008
Posts: 4,494
Features

Ptizef...

All very good ideas, improving usability substantially. Thanks for the good detail.

Some ideas easy, some not, as you might expect. Reliably finding the correct next waypoint on a route based on current position and course is not trivial. Consider a sailboat going to windward....

Anyway, after we release Version 1.3.4 (this week ), then we can look at and prioritize the next feature set. That is, after I take a few days code break....

Thanks again for the input

Dave
__________________

__________________
bdbcat is offline   Reply With Quote
Old 29-09-2009, 13:03   #77
Registered User

Join Date: Sep 2009
Location: Angers - France
Boat: Beneteau First 29 Ptizef
Posts: 731
Dave
Many thanks for your answer and more for the extraordinary great job your a doing .
regards
Jean Pierre Ptizef
__________________

__________________
Ptizef is offline   Reply With Quote
Old 07-10-2009, 20:37   #78
Marine Service Provider
 
bdbcat's Avatar

Join Date: Mar 2008
Posts: 4,494
GRIB on opencpn

Wake up, campers!

Its time to talk about GRIB support.
I'm a GRIB newbie myself, so I'm on a fast learning curve.

Here is what I know now:
1. Decoding GRIB files and drawing isobars and wind barbs on the chart is the simplest part of this problem.
2. The bigger problem is data management.

I visualize the simple case where GRIB files come onboard from some source, to be discussed next, and then all end up in a shoe box. The visualizer (opencpn) then needs to read the files in the shoe box and present the navigator with reasonable choices for:
a. Time period
b. Data to display
c. Animation?

Depending on the number of old files in the box, and the density of GRIB data available, there could be a file listbox containing hundreds of items.

Immediately I come up with issues
1. How can one be extra-super certain that the GRIB data on the screen represents what the user thinks it does? A one month old GRIB file is dangerous. And yet it is easy at night on a long lonely passage to misread tiny characters on the screen. Sevens can look like ones, etc. Think back on some passages and remember how long it took to work out a simple star sight when sleep deprived.....Happens all the time.
2. Who dumps the shoe box?

So, I have some questions, and invite random comments from sailors actually using GRIB files today.

1. Where do YOU actually get them from. I know they are "available everywhere on the internet", but actual user experience is requested here.
Feel free to give <code> examples of command lines, email headers, etc.

2. What do you do with them now? Which viewer? How long do you keep them? How often do you get them?

3. Is the data management issue trivial for you, or is it a pain?

4. Do they improve your passage planning really, or are they just cool to look at?

5. Do YOU trust the forecasts?

6. What would you see as a real quantum improvement in the way GRIBS are used in conjunction with ECS?

There is a lot to think about here. I'm sure by now you know my attitude on these things. I prefer not to load up opencpn with useless bloat, since we don't have to chase any commercial target.

If there is a good GRIB viewer that everyone likes to use, then we don't need it in opencpn. Alternatively, we can do something better in opencpn if we can visualize it.

To reiterate: Managing the GRIB data stream is the challenge. Drawing is simple.

Comments/Ideas/Suggestions/Flames?

Dave
__________________
bdbcat is offline   Reply With Quote
Old 08-10-2009, 01:54   #79
Registered User

Join Date: Mar 2008
Location: where my little boat is ;-) now Philippines
Boat: Catamaran Schionning Wilderness 1320, built myself
Posts: 170
zyGrib
thats my favourite, 6 languages, linux & windows,

and the MAIN reason: direct download AND display of downloaded files (offline)
data is from NOAA anyway

zyGrib is developed under Linux and for Linux. Anyhow a windows version has been compiled for those, for any real or virtual reason, still under windows.
For a MacOS version, compile sources with the port qt4-mac via macport.


Maybe instead of inventig the wheel anew, something can be used?
__________________
blubaju is offline   Reply With Quote
Old 08-10-2009, 03:39   #80
Registered User

Join Date: Mar 2008
Location: where my little boat is ;-) now Philippines
Boat: Catamaran Schionning Wilderness 1320, built myself
Posts: 170
forgot above: to make it (zyGrib) better, openCPN must go more into route planning, together with the boat polars and the grib data for fine tuning and the pilot data (like Virtual Pasage Planner) it could help a lot, but I think to go so far, that was not the intention of openCPN

have no idea if this is legally and practically possible: zyGrib as a sub routine to openCPN resulting in a transparent overlay over openCPN background as the first step.
__________________
blubaju is offline   Reply With Quote
Old 08-10-2009, 05:58   #81
Registered User

Join Date: May 2007
Location: Mostly on the boat. Occasionally at our condo in Port St Lucie, FL.
Boat: Manta 42 Sailcat -Toucan Dream
Posts: 82
Dave,

Here's my "user" input. I use grib files anytime I'm going offshore, if at all possible. I find them to be very accurate for 24 to 48 hour forecasts plus the displays out as far as 7 days help me to understand what the weather is expected to do even if the timing isn't very good 7 days out. So if a wind shift is expected to the north in 3 days and then build to 35 kts then I get out of range of an internet connection I can be on the look out for the wind shift and if it comes in 2 days or 4 days I'm better prepared.

As to your point on data management. I agree completely it is very important and it is easily solved by the grib US program that I've been using for years. They simply open the program to a download page that requires the user to select an area to get a new data file from their server. If you want to view an old data file you have to switch to a different screen and open the file. Files are stored with the date first in the name but I believe an extra layer of safety would be to emboss the date on the display the way you do water depth units on charts.

You are probably aware of this but just in case you're not, there's a lot of information at Global Marine Networks ~ Satellite Communications & Data Solutions that may be helpful to you in this new part of your project.

I trust the grib files as much or more than any other weather forecast. I'd probably describe it as "trust but verify". I check to see if actual weather is as forecast and check to see if not is it simply a timing change or radically different? If the latter is the case then there's reason for concern and I have to evaluate what that means for my situation. Maybe I look for a good anchorage, maybe I'm at sea and just double check to see that we're prepared for bad weather, or maybe I delay a departure etc.

I'm pretty happy with Grib.us but here are features I'd like to see added:

Enable the data to be displayed on our charts instead of their fairly crude high level outline chart. This can be a real pain since it doesn't have any locations for orientation. No cities or any other landmark. So it takes some work to be sure you really are looking at the correct location.

Emboss date on the display as mentioned previously.


I hope this helps and thanks again for what you do here.

Regards,
Chris
SV Toucan Dream
__________________
chris blair is offline   Reply With Quote
Old 08-10-2009, 06:37   #82
Registered User
 
Christian Van H's Avatar

Join Date: Oct 2008
Location: Princeton, NJ
Boat: Challenger Anacapa 42
Posts: 2,097
Images: 57
Hi Dave! I think including GRIB support into OpenCPN is a wonderful next step. I use ZyGRIB as my primary viewer, although I have tried several. In ZyGRIB, the program has a built in downloader which dl's the GRIB file to my assigned folder. It then immediately displays the new dl, making it impossible to get it "crossed up" with any older GRIB you might have laying around. Opening a GRIB fetched any other way, or an older saved GRIB should be by another method / window. Several GRIB programs allow the construction of animations, which help to visualize the coming weather, but in reality this is not a necessary feature. All thats needed is a forward and reverse button set to click the next forecast time up. These buttons could also change the "program clock", allowing the change of tides and currents too in "GRIB mode". It would be wonderful to see GRIBS displayed over real charts, with the ability to actually make out where in the world the window is zoomed on. With a route plotted, the interaction between all the available GRIB data and the boat could be calculated and displayed. Thanks to you and your team these are exciting times! Thanks again, Chris
__________________
www.anacapas.com

Here's to swimmin' with bowlegged women!
Christian Van H is offline   Reply With Quote
Old 08-10-2009, 06:49   #83
Senior Cruiser
 
sinbad7's Avatar

Cruisers Forum Supporter

Join Date: Sep 2003
Location: Ubatuba,SP,Brazil (Ex Norway)
Boat: (Ex) Alu. 60' yacht-"Eight Bells"
Posts: 2,697
Images: 57
Send a message via Skype™ to sinbad7
Why re-invent the wheel?

When there are so many free grib programs available?
They have no doubt spent a lot of time perfecting the software and have crossed most of the pitfalls. Why not allow the users to set up a link to their favorite grib program? Attachment shows my area at 12:47 UTC today.

I must admit I have little experience with gribs but this particular grib service looks fine to me:
Attached Thumbnails
Click image for larger version

Name:	UGRIB.jpg
Views:	320
Size:	134.4 KB
ID:	10380  
__________________
"And all I ask is a tall ship and a star to steer her by."
sinbad7 is offline   Reply With Quote
Old 08-10-2009, 15:44   #84
Senior Cruiser
 
sinbad7's Avatar

Cruisers Forum Supporter

Join Date: Sep 2003
Location: Ubatuba,SP,Brazil (Ex Norway)
Boat: (Ex) Alu. 60' yacht-"Eight Bells"
Posts: 2,697
Images: 57
Send a message via Skype™ to sinbad7
As a point of possible interest,please have a look at MY weather forecast pages which also includes the UGRIB service I mentioned in my last posting.

Available here:
__________________
"And all I ask is a tall ship and a star to steer her by."
sinbad7 is offline   Reply With Quote
Old 08-10-2009, 18:15   #85
Registered User
 
Christian Van H's Avatar

Join Date: Oct 2008
Location: Princeton, NJ
Boat: Challenger Anacapa 42
Posts: 2,097
Images: 57
Another way to get a GRIB at sea: Requesting grib files from Saildocs (2006-07-25) This is for SAILORS ONLY. Armchair captains need not apply...
__________________
www.anacapas.com

Here's to swimmin' with bowlegged women!
Christian Van H is offline   Reply With Quote
Old 08-10-2009, 19:01   #86
Senior Cruiser
 
sinbad7's Avatar

Cruisers Forum Supporter

Join Date: Sep 2003
Location: Ubatuba,SP,Brazil (Ex Norway)
Boat: (Ex) Alu. 60' yacht-"Eight Bells"
Posts: 2,697
Images: 57
Send a message via Skype™ to sinbad7
Suppose there are other ways too to receive grib files at sea by satellite or radio which can be replayed using a suitable browser?
__________________
"And all I ask is a tall ship and a star to steer her by."
sinbad7 is offline   Reply With Quote
Old 09-10-2009, 13:26   #87
Senior Cruiser
 
idpnd's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: Almería, ES
Boat: Chiquita 46 - Libertalia
Posts: 1,549
Code:
 1.  Where do YOU actually get them from.  I know they are "available everywhere on the internet", but actual user experience is requested here.
Feel free to give <code> examples of command lines, email headers, etc.
zygrib downloads these for free off the NOAA servers. perhaps the functionality/download logic could be adopted in some fashion? There are a few other open source programmes offering some level of grib support.

Quote:
2. What do you do with them now? Which viewer? How long do you keep them? How often do you get them?
Zygrib is good for viewing as well. They are stored to a certain directory, kept indefinitely usually. I get them whenever I have internet access.

Quote:
3. Is the data management issue trivial for you, or is it a pain?
Trivial as I download a fresh one often, which is then displayed on-screen right away. I can see your point about the navigational risks (although each captn is responsible for their weather analysis really!). This could be overcome by tightly integrating a system time measure into opencpn as time zero. Gribs could be colour coded (eg force greyscale = old, colours for current/future data, similar to own boat icon) or a traffic light icon or similar warning symbol could be used alongside display of the date on the grib.

Quote:
4. Do they improve your passage planning really, or are they just cool to look at?
Particularly for sailing trips, it is hugely important to have good weather data. It is of course always a safety feature at sea, or even when anchoring.

Quote:
5. Do YOU trust the forecasts?
There are certain probabilities but the claimed validity for the 3-day forecast is around 99% (bearing in mind that 95.7% of stats are made up on the spot)

Quote:
6. What would you see as a real quantum improvement in the way GRIBS are used in conjunction with ECS?
The aforementioned programme time scale would ideally be adapted for the journey time during planning/routing exercises. Just imagining the complexity involved in programming this sort of thing gives me a bit of a headache

Quote:
To reiterate: Managing the GRIB data stream is the challenge. Drawing is simple.
Perhaps you've been following the improvised google earth overlays via tif2bsb on the charts thread; visualisation of an open standard KML overlay would perhaps permit people to freely develop third-party overlays.
__________________
idpnd is offline   Reply With Quote
Old 09-10-2009, 14:16   #88
Senior Cruiser
 
idpnd's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: Almería, ES
Boat: Chiquita 46 - Libertalia
Posts: 1,549
Incidentally, regarding bloat, would it be difficult to implement hooks for plugins and extensions, thus permitting the development, installation & removal on an "API" basis?
__________________
idpnd is offline   Reply With Quote
Old 09-10-2009, 16:21   #89
Registered User
 
LeaseOnLife's Avatar

Join Date: Apr 2008
Location: Around once, back to work, for a while :-(
Boat: Sailboat
Posts: 967
Grib files via Ham radio or Marine SSB

Some people use satellite phones to get their grib files and several services compress data and charge money for the compressed data. Then the satellite phone connection costs some serious money too

For people without a HAM license, but an SSB radio plus a modem: A service called sailmail SailMail is available, specifically catering to the bandwidth deprived people off shore. Besides grib file, the weather text forecasts for around the world are available from a "catalog". sailmail is NOT free. There are other services similar to sailmail.

For people with HAM license, the above sailmail catalog becomes available for free, plus many more shore station to connect too. Look at http://winlink.org

Sailmail and winlink give you the ability to receive and send short, mostly text, emails via shortwave radio. The FREE option causes many offshore sailors to get their HAM licenses.

I use winlink with great success, specifically off shore when the background noise dies down, I almost always get a connection, get my text weather forecasts, selected gribs for wind and waves plus ocean currents. I can also get images of watherfaxes, but we have a seperate weatherfax onboard which spits out these images from the weatherfax broadcasts.
__________________
LeaseOnLife is offline   Reply With Quote
Old 09-10-2009, 16:37   #90
Registered User
 
LeaseOnLife's Avatar

Join Date: Apr 2008
Location: Around once, back to work, for a while :-(
Boat: Sailboat
Posts: 967
Grib data content: Not just wind and barometric pressure !!!!!!!!!

Drawing is simple.... I would be careful with this statement:

There are many types of data one can get as a grib file. Please make sure to not only implement the display of barometric pressure and wind forecasts. To many other programs do just that. As sindbad said, why re-invent the wheel. To bet better, opencpn needs to display more types of data than just wind and pressure.

Examples:
  • The RTOFS model give currents and water temperature, I use this for the gulf stream region.
  • The WW3 model can give you wind wave height, period and direction plus swell height, period and direction.
  • Quickscat data. These are actual measurements, not forecast data.
I mentioned winlink and sailmail in a post above as a source for grib files. A program to access the data from both is called airmail2000: The Airmail Home Page (free)

It comes with a grib viewer which does diesplay, isobars, winds, temps, currents, waves... It has a very crude GUI, but it is able to show way more types of data than the Zygrib. I continue to try out every free or not so free Grib data display. But I always had to resort back to "View Fax", part of the airmail2000 package.
__________________

__________________
LeaseOnLife is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Yet anothr of my stupid requests Little Otter Multihull Sailboats 2 30-06-2008 00:29
Any requests for pics at Strictly Sail Oakland? Redbull addict Monohull Sailboats 0 30-03-2007 19:33
Capt.Jack requests permission to come aboard canatc1 Meets & Greets 8 10-04-2006 17:54


Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 05:39.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.