WeatherFax ...

[rgleason]

Sean will do some testing in 3 days. No computer here right now.

Sent from my SCH-I545 using Cruisers Sailing Forum mobile app

[rgleason]

git pull, compile
latest commit 9462aa25f2 nohal authored 2 hours ago
...105 warnings, 0 errors. See attached doc file with the warnings.

Uploaded new install file to Opencpn Beta File thingie rguser rgpass

Under 3.2.2 PI Win look for
weatherfax_pi-1.2-ov3.2.2-g-win32

[rgleason]

After downloading 48HrSurface_Valid201302011200.wav from Opencpn Beta File Thingie Soundfiles, I opened the WAV file in Windows Media and played it.
While this is being played I brought up Opencpn 3.2.2 and started Weatherfax_pi and selected Retrieve > Audio.

The plugin started receiving the fax that was being played by Windows Media, bringing the Fax file in line by line, as the sound was converted to a fax image.

If you let media player and weatherfax plugin continue too long after the fax is completed, it will all start over again....so you willl have to wait, until you can save it. The second time around the image was phased correctly and the skew seemed to be good. Once the fax is pretty much complete, hit "Stop" then "Next". Then get the image coordinates set by trying some and then lay on top of the Opencpn Chart, then Edit again and adjust the coordinates... after three or four tries I got it close... see attached.

It works! Retrieve > Audio seems to work fine... The wav file is brought up in Windows Media and then Opencpn Weatherfax Plugin reads the sound line by line... How nice! I need to order the RTLSDR dongle and give it a try! Thank you Sean and Pavel this feature seems to be working fine!

The only question I have, is there a way to "Save" the converted Fax Image for later use? (By the way I missed taking a screenshot of the overlay on the chart...sorry)

[seandepagnier]

Originally Posted by rgleason

The plugin started receiving the fax that was being played by Windows Media, bringing the Fax file in line by line, as the sound was converted to a fax image.

Are you playing out your speakers and using a microphone, or do you have an audio cable going from line out to line in?

If you let media player and weatherfax plugin continue too long after the fax is completed, it will all start over again....so you willl have to wait, until you can save it.

What do you mean start all over again? Does your media player repeat or something?

The second time around the image was phased correctly and the skew seemed to be good. Once the fax is pretty much complete, hit "Stop" then "Next". Then get the image coordinates set by trying some and then lay on top of the Opencpn Chart, then Edit again and adjust the coordinates... after three or four tries I got it close... see attached.

It works! Retrieve > Audio seems to work fine... The wav file is brought up in Windows Media and then Opencpn Weatherfax Plugin reads the sound line by line... How nice! I need to order the RTLSDR dongle and give it a try! Thank you Sean and Pavel this feature seems to be working fine!

To be clear, the RTLSDR is primarily used for AIS and VHF. This is all I have ever done with mine.

It can possibly pick up some satellite weather faxes (using double helix special antenna you can easily build) but this plugin cannot decode them, you need a different program.

It can also pick up normal SSB weather fax at least so I've heard, but never tried myself. There are 2 ways to do this:

1. Order an up-converter to convert the low frequency SSB signals to the range the dongle can sample. This is going to cost $40 or so and be most reliable probably.

2. Break the dongle open and solder the antenna wire to the correct pin on a very small chip leg and make other modifications possibly adding resistors and capacitors, then use a hacked driver (I think you must compile from source but maybe it's merged now) you can in theory bypass the demodulator, so feed your antenna directly into the adc, and receive SSB signals as well with lower quality (but enough for weather fax, I don't know) The benefit here is you could actually pick up several weather faxs on different frequency all at the same time since you get everything from 0-30mhz all the time.

The only question I have, is there a way to "Save" the converted Fax Image for later use? (By the way I missed taking a screenshot of the overlay on the chart...sorry)

You can export to kap file, but I didn't support exporting to other image formats, would not be hard to implement.

[rgleason]

It appears to me that Weatherfax's Image Wizard contains a Georeference Tool which calculates and establishes how to overlay a map image onto the charts, this requires that certain information be known, including at least several lat/long coordiinates and type of projection..(well actually, the image gets converted to mercator, so that is known).

It would be very nice if there was a standard for adding georeference data to the header in the image exim data area, that could be read the next time the image is loaded into Opencpn through the Weatherfax Plugin, so that the user does not have to reestablish this data....

Here are some links to georeferencing information.
Georeferencing Calculator Manual v2
Georeferencer - Online Georeferencing Tool For Scanned Maps (OldMapsOnline.org)
http://www.library.yale.edu/MapColl/...ned%20Maps.pdf
GIS Manual: Exchanging Data between GIS and CAD Formats

http://help.arcgis.com/en/arcgisdesk...0000006000000/

The next thing to do is to find out what the standard is to add georeference data to the header....so that perhaps it can be done to the weatherfax images where the coords and georef data are known...?

[rgleason]

Ok, I'm not going to go any further on this because its my guess you guys all know this stuff like the back of your hand...

Open Geospatial Consortium - Wikipedia, the free encyclopedia

[seandepagnier]

Originally Posted by rgleason

It appears to me that Weatherfax's Image Wizard contains a Georeference Tool which calculates and establishes how to overlay a map image onto the charts, this requires that certain information be known, including at least several lat/long coordiinates and type of projection..(well actually, the image gets converted to mercator, so that is known).

It would be very nice if there was a standard for adding georeference data to the header in the image exim data area, that could be read the next time the image is loaded into Opencpn through the Weatherfax Plugin, so that the user does not have to reestablish this data....

Rick,

Consider that weather fax opens various types of images, and I'm pretty sure many do not have an exim data area. Also wav files, as well as decode directly from the sound card. There is no exim data area.

Perhaps you want the plugin to save all the images to disk in an image format which has this data area so it can load them the next time it starts?

Currently the only way to use the images persistently is to export them to kap and load as charts.

[rgleason]

Are you playing out your speakers and using a microphone, or do you have an audio cable going from line out to line in?

Maybe I am doing this incorrectly...
1. Start Windows Media and open the WAV file.
2. Start Opencpn and Weatherfax and then select Retrieve > Audio Capture.

The reason I think this works is that when I do just #2 the screen is just speckles of black, but when I do #1 and #2 I get an image and I hear sound coming from the Windows Media Player that seems to be converted by Weatherfax...
===
Am I supposed to be outputting sound using Windows Media.. then using a microphone to read the sound in??
===
I wonder why an image appears when I don't output to speaker and then have a mic?

To be clear, the RTLSDR is primarily used for AIS and VHF. This is all I have ever done with mine.

It can possibly pick up some satellite weather faxes (using double helix special antenna you can easily build) but this plugin cannot decode them, you need a different program.

It can also pick up normal SSB weather fax at least so I've heard, but never tried myself. There are 2 ways to do this:

1. Order an up-converter to convert the low frequency SSB signals to the range the dongle can sample. This is going to cost $40 or so and be most reliable probably.

2. Break the dongle open and solder the antenna wire to the correct pin on a very small chip leg and make other modifications possibly adding resistors and capacitors, then use a hacked driver (I think you must compile from source but maybe it's merged now) you can in theory bypass the demodulator, so feed your antenna directly into the adc, and receive SSB signals as well with lower quality (but enough for weather fax, I don't know) The benefit here is you could actually pick up several weather faxs on different frequency all at the same time since you get everything from 0-30mhz all the time.

Thanks, for the heads up, Sean. I had thought I could receive weatherfaxes. Well I've ordered anyway now and will try it for AIS with the RTLSDR plugin and maybe also try the wfax thing somehow, using wximg or get the upconverter or something too...

It would be really nice to be able to receive weatherfax reliably without having to purchase SSB and Pactor and all that expensive gear! I am sure this situation is going to get better and better... I don't think I am going to do #2 until I am sure that there is a definite path...

[rgleason]

Perhaps you want the plugin to save all the images to disk in an image format which has this data area so it can load them the next time it starts?

Yes, since when the image wizard completes and the image is presumably overlaid on the chart in the correct location, I was hoping this georeferencing data could be saved in something like an image exim header, so that the plugin could then use that information the next time the image is loaded. Thus saving the user from having to reestablish the georef data again by trial and error...a longer process.

I don't know if this is too complicated to do, but I think it would be very useful and make it easier for the user to go back to yesterday's images to check what the weatherfax said at that point, etc....

[rgleason]

Quote:
The only question I have, is there a way to "Save" the converted Fax Image for later use? (By the way I missed taking a screenshot of the overlay on the chart...sorry)
You can export to kap file, but I didn't support exporting to other image formats, would not be hard to implement.

====

Maybe we could "Save with Georeference Data" too? Then perhaps the plugin would automatically load it, by reading the exim header? It might be worth thinking a little bit about how this works and how best to do this, because we don't want to complicate the process too much, but perhaps it can be made to become an integral "last step" for the wizard? With confirmation by the user perhaps?

[rgleason]

What do you mean start all over again? Does your media player repeat or something?

Yes, Windows Media Player looped back and started again, and the image on the screen blanked out....and then started writing again....so I just waited until it finished and clicked Stop and Next.... The second time around skew and phase were right on....

[rgleason]

Here is a polar fax file that I've audio recorded using Windows Media to play the WAV file 2001-06-21-09-00-GYA-11086.wav
Open Opencpn and Weatherfax immediately and select Retrieve Audio Capture
and the WxFax starts retrieving... Then after it has reached the bottom, hit Stip and then Next... The try to georeference the file using the georeference information...Then overlay on charts... this one is not correct because gridlines in both directions need to be straight..

Shown in reverse order here, final to previous to first.

[rgleason]

Perhaps you want the plugin to save all the images to disk in an image format which has this data area so it can load them the next time it starts?

Currently the only way to use the images persistently is to export them to kap and load as charts.

Because I don't know the chart file format very well, it took me awhile to realize that the Kap file is mercator (flat) format and probably has the georef data in it...just like all the chart bsb images etc...

I think users are generally just as thick about this ...(with the exception of Opencpn active users of course...) so I think that somehow we need to make it clearer that if you want to save the converted image file (mercator format) with its georeferencing data, so that the information can be loaded again easily without having to input the coords lat/long etc. again.... you must save a KAP file..

BUT wouldn't it be better to just make that the last step in the Wizard Process...somehow... a User activated confirmation that the image is in the right place and can now be "Saved as KAP for easy reuse with coordinates"

Just an idea that might help all users fully utilize the Wizard features.

[seandepagnier]

Originally Posted by rgleason

Maybe I am doing this incorrectly...
1. Start Windows Media and open the WAV file.
2. Start Opencpn and Weatherfax and then select Retrieve > Audio Capture.

The reason I think this works is that when I do just #2 the screen is just speckles of black, but when I do #1 and #2 I get an image and I hear sound coming from the Windows Media Player that seems to be converted by Weatherfax...

It should work but explains why the image quality is poor. Try clapping your hands or singing while it's converting the fax. This is why it's best to have a cable from the radio to the computer rather than just setting the laptop next to the radio (which maybe works but not well)

It would be really nice to be able to receive weatherfax reliably without having to purchase SSB and Pactor and all that expensive gear! I am sure this situation is going to get better and better... I don't think I am going to do #2 until I am sure that there is a definite path...

This has nothing to do with pactor and never did. I use a tecsun PL-600 which cost $45. The rtlsdr with upconverter is relatively inexpensive, or the rtlsdr with hardware hack for ssb by far the cheapest if it actually works.

Originally Posted by rgleason

Yes, since when the image wizard completes and the image is presumably overlaid on the chart in the correct location, I was hoping this georeferencing data could be saved in something like an image exim header, so that the plugin could then use that information the next time the image is loaded. Thus saving the user from having to reestablish the georef data again by trial and error...a longer process.

I don't know if this is too complicated to do, but I think it would be very useful and make it easier for the user to go back to yesterday's images to check what the weatherfax said at that point, etc....

It should save the coordinates so you can select them and not have to re-enter every time.

Originally Posted by rgleason

Maybe we could "Save with Georeference Data" too? Then perhaps the plugin would automatically load it, by reading the exim header? It might be worth thinking a little bit about how this works and how best to do this, because we don't want to complicate the process too much, but perhaps it can be made to become an integral "last step" for the wizard? With confirmation by the user perhaps?

Possibly a feature for a future version.

Originally Posted by rgleason

Yes, Windows Media Player looped back and started again, and the image on the screen blanked out....and then started writing again....so I just waited until it finished and clicked Stop and Next.... The second time around skew and phase were right on....

I think it helps to start capturing a few seconds before playing the wav otherwise it will miss the start signal and not get the phasing.

[seandepagnier]

Originally Posted by rgleason

BUT wouldn't it be better to just make that the last step in the Wizard Process...somehow... a User activated confirmation that the image is in the right place and can now be "Saved as KAP for easy reuse with coordinates"

Just an idea that might help all users fully utilize the Wizard features.

I have a better idea. Make the plugin able to open kap files. Then add an option to export all the files at exit and open them all when the plugin starts up.