Free Routing Software. qtVlm

[maitai]

Great! Thanks Tore

[sinbad7]

Phil..

Tested the grib1 format with OpenCPN but had to re-name it to .grb
and it does not show any stream value,only direction??

Tested also with qtVlm Routing Optimizer,which did NOT load and was
unable to read the .grb format ??


Regards

[sinbad7]

Phil..

qtVlm unable to read the present tidal stream data in .grb format.
Has there been a change in the latest v.?

The .grb format reads, (more or less) into OpenCPN...

Tore

[maitai]

This grib is not referenced in qtVlm. If I add it, it opens but without any data being displayed. I don't know why yet.

[sinbad7]

Phil...


Not the fault of qtVlm I think,it reads the old .grb stream format perfectly.

Also OpenCPN reads the old format displaying all including direction and speed.


I have advised the grib provider accordingly..something wrong with their conversion

from the .grb2 format.



Tore

[sinbad7]

Phil... FYI ...

Kai..

OK,I understand it is a complex system which can not be converted EXACTLY to the old .grb format,making it incompatible to both Fugawi ENC 4.5 as well as the qtVlm Route Optimizing program,AND as far as I can make it,partially incompatible also with OCPN. The popular,Android based OruxMaps is also not able to read the converted .grb format. BUT,if that´s a good as it can get,in the meantime,until the various nav. progs catch up with the new version .grb2, at least we have some streaming facility in OCPN,and thank you for making that available.

I will pass on your U and V format description to the creators of qtVlm but I doubt if they will make any complicated changes only as a temporary stop gap.

Thanks for taking the time to explain.

Regds
Tore
----------------------------------------------
Tore,

As I mentioned in an earlier post, the two files are different in terms of time of forecast:Grib format has a dedicated time field called reference time in the Product Definition Section octets 13-17.

Further there is in octet 18 a forecast time unit defined (ie. Year or month… or minute) in octets 19 and 20 there is a timeinterval defined in units of octet 18 .

The old format has octets 13-17 step up by 30 minutes for each forecast timestep, i.e first U and V records have date00:30, Second have date01:00 …
The new format has for the whole file octets 13-17 be constant date00:00 and increment octets 19 and 20 such that each pair (U,V) has an additional 30 minutes timestamp.

This can explain the fact that the routing program does not accept the new format ( I found a Grib Package from a Science Institution which can not handle the minutes time intevall either).

Regards
Mit freundlichen Grüßen
Kai Jancke

[maitai]

Grib2 format will be supported quite soon in qtvlm, that will fix it all

[sinbad7]

FYI the converted .grb files from ftp://ftp.bsh.de/Stroemungsvorhersagen/grib1/
no longer work in either qtVlm or OCPN with the following messages attached.

The developers of qtVlm tells me that they are very shortly going to have a new release compatible with .grb2 so that is good news. From here we just copy/paste the Optimized Route in .kml format to OCPN.

Tore

[sinbad7]

Sorry,forgot the attachments with the error messages:

Tore

[xiurong]

what's the difference between the 1st and the 3rd one in the download list

[maitai]

Cannot understand the question... 1st is 3.3.0 and third is 3.4.1...
A lot of differences, described in previous posts in this thread.

[maitai]

Btw qtVlm 3.4.3 is released for windows (for mac users it's gonna take a while due to bad internet connection from our compiler)
It contains:
- Much reduced memory consumption
- A brand new English translation (many thanks to John from this forum)
- A better and faster routing module
- Support for grib2 format
- Support for waves
- Better support and management of kap files
- Ability to simplify/optimize a route by segments
- Adaptation to new zyGrib download procedure (old one will be outdated in a few days)
- Some few bug fixes and many other small or bigger improvements

[hwecken]

Hello maitai,
i installed 3.4-3 and give the current Grib in grib2 format from BSH a try.
The grib is loaded without any problem (see screenshot) but there are no data diplayed. In the menu "Map type" i have selected "current grib".
Any idea ?
vb Hartmut

[maitai]

Yes we know that. In fact there is the same problem in their grib V1 files. It's something weird in their grib files that prevent us from interpolating correctly. We are in touch with them so let's hope we'll find a solution or that they will remove their empty (zeroed) columns and lines

[hwecken]

thanks for Info