Upgraded to 3.0.2 - Get chart Errors

[svkatielee]

I upgraded from 2.5 yestyerday. I can't get many of my charts to load.
I get in the description of the chart (popup when I hover over the blue button at bottom)
"Warning: Chart georef accuracy is poor."
And in the opencpn.log file I get:

<code>21:21:08 PHT: Initializing Chart /media/Acer/Charts/CPN Phillipines charts/4716_new.kap
21:21:08 PHT:    Chart projection is UNKNOWN, assuming embedded georef: /media/Acer/Charts/CPN Phillipines charts/4716_new.kap
21:21:09 PHT:    VP Final Check: Georeference Chart_Error_Factor on chart /media/Acer/Charts/CPN Phillipines charts/4716_new.kap is 0.981834
</code>

These were custom converted charts, as are most of my charts in this area, but all the charts created by the same guy have quit working with this release.
Anyone have any idea what is wrong and if I can do something (like edit the *.kap files directly) to fix them?

Here is the head of that file:

! Created by mc2bsbh beta07 - Use at your own risk!
VER/2.0
BSB/NA=Palawan,NU=4716
    RA=6708,8000,DU=93
KNP/SC=200000,GD=WGS84,PR=UNKNOWN,PP=UNKNOWN
    PI=UNKNOWN,SP=UNKNOWN,SK=0.0,TA=90.0
    UN=FATHOMS,SD=UNKNOWN
    DX=54.35,DY=54.35
REF/1,2234,1015,11.5,118
REF/2,6327,1010,11.5,120
REF/3,6331,7163,8.5,120
REF/4,1220,7176,8.5,117.5
PLY/1,11.9958532,116.909524
PLY/2,8.10209557,116.905508
PLY/3,8.09385336,120.181719
PLY/4,11.9894052,120.184339
DTM/0,0
IFM/7
RGB/1,52,44,25
RGB/2,53,44,35
RGB/3,49,51,49
RGB/4,71,63,53
RGB/5,74,67,45
...

Thanks.

[cagney]

Generally when I see your error, it's exactly what it says - poor geo-referencing. Normally a simple error by the person doing the conversion. It's no problem correcting the geo-referencing, once you know the problem. One way, is to edit the header. Much of this is described in the opencpn.org wiki conversion handbook.
I don't think that this code has changed between 2.5 and 3.0.x, with reservation for the possibility that the changing polyconical chart code has something to do with it. I have no such indication in the few conversions I have done lately, though.
If you can publish a small chart here, I can help you to find out what's up.

Thomas

[bdbcat]

Thomas & svkatielee....

OpenCPN Version 3 does a better job of detecting KAP files with unknown projection parameters. So, the problem is exactly what the log says. We have no idea how to project the attached REF points onto a Mercator surface. 2.5 assumed "UNKNOWN= Mercator".

Simple solution may be to change "PR=UNKNOWN" in header.

Hope this helps
Dave

[cagney]

Thanks Dave.
I read the original error message a bit quick, and forgot about changed "UNKNOWN" handling.
It's hard to think of a chart with unknown projection, and the change in how O treats "UNKNOWN" is logical.
Unfortunately a lot of the tools out there, to help with conversion of charts, creates "simplified" kap headers, similar to the one in post #1 . We can expect more posts with the same question. Probably a FAQ candidate!
Thomas

[svkatielee]

Thanks guys, that did change the error messages. I'll try to research the chart conversion some more. I didn't create these charts, I don't have the original material to redo them. I have around 200 of these and they are the only ones to show details around Palawan, so I need them to work.

Here is the new error after changing the PR= and PP=

07:30:00 PHT: LOGBOOK:  2012-07-19 23:30:00 UTC  DR Lat    9.76580 Lon  118.72870
07:30:14 PHT: Initializing Chart /media/Acer/Charts/PHILIPPINE CHARTS (105)/P4716.kap
07:30:27 PHT: Initializing Chart /media/Acer/Charts/CPN Phillipines charts/4716_new.kap
07:30:27 PHT:    ifs_bufsize too small PostInit() on chart /media/Acer/Charts/CPN Phillipines charts/4716_new.kap
07:30:27 PHT:    OpenChartFromStack...Error opening chart /media/Acer/Charts/CPN Phillipines charts/4716_new.kap... return code 2
07:30:27 PHT: Initializing Chart /media/Acer/Charts/CPN Phillipines charts/4716_new.kap
07:30:27 PHT:    ifs_bufsize too small PostInit() on chart /media/Acer/Charts/CPN Phillipines charts/4716_new.kap
07:30:27 PHT:    OpenChartFromStack...Error opening chart /media/Acer/Charts/CPN Phillipines charts/4716_new.kap... return code 2

The 'return code 2' and the ifs_bufsize I don't know where to lookup.

[bdbcat]

svkatielee...

Hmmm.

Can you send me a small KAP chart with the indicated problem? Preferably one with "pr = MERCATOR" correction made....

I'll debug it.

Thanks
Dave

[cagney]

svkatielee

I don't have the original material to redo them

You don't need the original material. Try "imgkap" or "bsb2tif" to extract the pictures from the kap chart. Should work, unless something strange is going on....
THomas

[svkatielee]

Thank you very much for the help. They work now. In the process of finding one small enough to upload, I discovered I was not carefull enough in the editor. I had tried vi (linux) and it changed the last line.
So the resulting fix was
for i in `ls *.kap` ; do echo $i; cat $i|sed 's/PR=UNKNOWN/PR=MERCATOR/'>../CPN_Philippines_charts/$i; done

Which only changed the one word in each file.
Thanks again, Larry

[cagney]

Dave

Testing the chart UNKNOWN behavior with a GNOMONIC chart, georeffed as if it was a merc. O does not recognize GNOMONIC so it is UNKNOWN. So far so good. In spite of this my screen becomes a mess with bits and pieces of the chart, when O still tries to display the chart.
Wouldn't it be better to just silently drop the whole thing, with just the note in the log?
Chart attached. Note the pdf extension. This was away around size limits for other extensions!
2484.7z.pdf

Thomas