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Old 11-12-2014, 11:05   #331
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Re: OpenCPN Beta Version 3.3.2330 Released

Quote:
Originally Posted by rgleason View Post
Hakan:

Yes!! We do it whenever setting up our CAD program on a different screen. It must be done to get the drawing image scaled correctly, otherwise the plan and proportions are all screwy!

I encourage this improvement in settings for greater proportional accuracy.
OK Rick, yes I see. But a flat CAD view is easier. Here we have to shrink Mercator's upper spreading? That will be a new feeling to see a map or a chart with such adjustments? A great circle will be straight??
Thanks
Håkan
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Old 11-12-2014, 11:10   #332
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Re: OpenCPN Beta Version 3.3.2330 Released

Why do we care about the scale of the on-screen image? What will anyone use it for?

Fabbian
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Old 11-12-2014, 11:56   #333
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Re: OpenCPN Beta Version 3.3.2330 Released

Quote:
Originally Posted by jonasaberg View Post
Dave,
After releasing v4.0, laying back for a while, counting clouds with a smile of confidence for a job well done....

Maybe this with quilting TM could be worth a second look for v4.2? I seem to remember that other programs succesfully quilt TM .

I was meaning to check flyspray, but the site seems down?

/Jonas
Jonas

O is quilting Tmerc with Tmercs but not with Mercator charts.
I'm not aware of a program that does this.
Programs, like PolarNavy, seems to do it, but it's because it, on the fly, re-projects the tmercs to mercs. For this to work the tmerc kap files must contain polynomial coefficients. The old Swedish tmercs from Solteknik does not contain these. A good test, that I haven't done, would be to try to load a few Swedish tmercs in PolarNavy. My guess is that they will not show.
Talking about Swedish tmercs ...... Sjöfartsverket has reverted back to Mercator charts only. The only current Swedish tmercs are some yachting charts, and these are not (I think) available as kaps. This was a kind of a "stealth" decision a few years back, I don't have a date.

Thomas
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Old 11-12-2014, 13:38   #334
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Re: OpenCPN Beta Version 3.3.2330 Released

Quote:
Originally Posted by cagney View Post
Jonas

........ For this to work the tmerc kap files must contain polynomial coefficients. ......

Thomas
Thomas..
The charts I reffered to here: OpenCPN Beta Version 3.3.2330 Released and also showed here OpenCPN Beta Version 3.3.2330 Released has this header:
Code:
! 2011 imgkap 1.11 - at 20/03/2013 from hg932-04.png
!Copyright: Hydrographica. Generated by Sping AB
VER/3.0
CRR/Copyrights:
    Hydrographica, Oskarsvagen 29, 172 76 Sundbyberg, Sweden
    www.hydrographica.se
BSB/NA=hg932-04 Kråksundsgap   
    NU=hg932-04_1,RA=3894,4624,DU=254
KNP/SC=10000,GD=WGS84,PR=TRANSVERSE MERCATOR
    PP=11.3082833333333,PI=UNKNOWN,TA=90.0,UN=METERS
    SD=AMSL,SK=0.0,DX=1.26,DY=1.26
KNQ/EC=WE,GD=WGE,VC=MSL,SC=AMSL,GC=UB,RM=INVERSE
    PC=TC,P1=11.3082833333333,P2=1.00,P3=0.00,P4=NOT_APPLICABLE
DTM/0,0
CED/SE=2011,RE=01,ED=20/03/2013
REF/1,2650,1192,58.116666666667,11.466666666667
REF/2,330,1193,58.116666666667,11.416666666667
REF/3,329,4116,58.083333333333,11.416666666667
REF/4,2652,4116,58.083333333333,11.466666666667
PLY/1,58.1290333404371,11.4120166633683
PLY/2,58.0787500049974,11.4120833333397
PLY/3,58.0787333383388,11.477433333336
PLY/4,58.0921166716303,11.4774666667415
PLY/5,58.0921161337441,11.4917333333766
PLY/6,58.0986000049816,11.4917333333848
PLY/7,58.0986166716098,11.4774500001101
PLY/8,58.1290166715111,11.4775000002798
CPH/0.00
WPX/1,-528926.3253213,46389.7884580,-6.1948529
WPY/1,5098034.7551778,26.4273032,-87705.3851561
PWX/1,11.409534122499900,0.000021552063610,0.000000005493594
PWY/1,58.130252113969300,-0.000000000604884,-0.000011397273256
ERR/1,0,-1,0.000001705362,0.000013027236
ERR/2,0,1,0.000011699304,0.000013809318
ERR/3,-2,1,-0.000007404906,0.000019303606
ERR/4,2,-1,-0.000005999760,-0.000046140160
OST/1
IFM/6
RGB/1,249,156,34
RGB/2,255,255,204
...........
Can you assess a possible way to use them in a more proper way in OCPN according to your specification above?
Thanks
Håkan
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Old 11-12-2014, 14:54   #335
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Re: OpenCPN Beta Version 3.3.2330 Released

Quote:
Originally Posted by Hakan View Post
Thomas..
The charts I reffered to here: OpenCPN Beta Version 3.3.2330 Released and also showed here OpenCPN Beta Version 3.3.2330 Released has this header:
Code:
! 2011 imgkap 1.11 - at 20/03/2013 from hg932-04.png
!Copyright: Hydrographica. Generated by Sping AB
VER/3.0
CRR/Copyrights:
    Hydrographica, Oskarsvagen 29, 172 76 Sundbyberg, Sweden
    www.hydrographica.se
BSB/NA=hg932-04 Kråksundsgap   
    NU=hg932-04_1,RA=3894,4624,DU=254
KNP/SC=10000,GD=WGS84,PR=TRANSVERSE MERCATOR
    PP=11.3082833333333,PI=UNKNOWN,TA=90.0,UN=METERS
    SD=AMSL,SK=0.0,DX=1.26,DY=1.26
KNQ/EC=WE,GD=WGE,VC=MSL,SC=AMSL,GC=UB,RM=INVERSE
    PC=TC,P1=11.3082833333333,P2=1.00,P3=0.00,P4=NOT_APPLICABLE
DTM/0,0
CED/SE=2011,RE=01,ED=20/03/2013
REF/1,2650,1192,58.116666666667,11.466666666667
REF/2,330,1193,58.116666666667,11.416666666667
REF/3,329,4116,58.083333333333,11.416666666667
REF/4,2652,4116,58.083333333333,11.466666666667
PLY/1,58.1290333404371,11.4120166633683
PLY/2,58.0787500049974,11.4120833333397
PLY/3,58.0787333383388,11.477433333336
PLY/4,58.0921166716303,11.4774666667415
PLY/5,58.0921161337441,11.4917333333766
PLY/6,58.0986000049816,11.4917333333848
PLY/7,58.0986166716098,11.4774500001101
PLY/8,58.1290166715111,11.4775000002798
CPH/0.00
WPX/1,-528926.3253213,46389.7884580,-6.1948529
WPY/1,5098034.7551778,26.4273032,-87705.3851561
PWX/1,11.409534122499900,0.000021552063610,0.000000005493594
PWY/1,58.130252113969300,-0.000000000604884,-0.000011397273256
ERR/1,0,-1,0.000001705362,0.000013027236
ERR/2,0,1,0.000011699304,0.000013809318
ERR/3,-2,1,-0.000007404906,0.000019303606
ERR/4,2,-1,-0.000005999760,-0.000046140160
OST/1
IFM/6
RGB/1,249,156,34
RGB/2,255,255,204
...........
Can you assess a possible way to use them in a more proper way in OCPN according to your specification above?
Thanks
Håkan
Håkan

Interesting!
The Solteknik tmercs I was talking about are from 1998.
I also have some very recent Mercator charts from Solteknik, but his is the first time I see lines like
Quote:
WPX/1,-528926.3253213,46389.7884580,-6.1948529
WPY/1,5098034.7551778,26.4273032,-87705.3851561
PWX/1,11.409534122499900,0.000021552063610,0.000000005 493594
PWY/1,58.130252113969300,-0.000000000604884,-0.000011397273256
ERR/1,0,-1,0.000001705362,0.000013027236
ERR/2,0,1,0.000011699304,0.000013809318
ERR/3,-2,1,-0.000007404906,0.000019303606
ERR/4,2,-1,-0.000005999760,-0.000046140160
in charts from them.
My guess is that it will work, and that they are present to facilitate a re-projection.
To answer your question.... You can test your self, if a re-projection is possible. Check out this page
Nautical Chart Reprojector | Digital Coast
If it works, you should end up with a Mercator chart that should be OK in O.

Thomas
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Old 11-12-2014, 18:42   #336
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Re: OpenCPN Beta Version 3.3.2330 Released

Quote:
Originally Posted by cagney View Post
Interesting!
... but his is the first time I see lines like

Code:
WPX/1,-528926.3253213,46389.7884580,-6.1948529
WPY/1,5098034.7551778,26.4273032,-87705.3851561
PWX/1,11.409534122499900,0.000021552063610,0.000000005493594
PWY/1,58.130252113969300,-0.000000000604884,-0.000011397273256
ERR/1,0,-1,0.000001705362,0.000013027236
ERR/2,0,1,0.000011699304,0.000013809318
ERR/3,-2,1,-0.000007404906,0.000019303606
ERR/4,2,-1,-0.000005999760,-0.000046140160
...

Thomas
Me neither. Intriguing.

These days I don't have time to dive in to something like this, but I'll be very interested to hear anything and everything anyone comes up with.

-dan
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Old 12-12-2014, 09:06   #337
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Re: OpenCPN Beta Version 3.3.2330 Released

Quote:
Originally Posted by bdbcat View Post
Gilletarom...

1. Mercator projection: On paper charts, distances measured manually with dividers are converted to actual distances using the latitude scale. This is normal navigation practice. Of course, at high latitude, there will be distortion, horizontal vs vertical. This is the nature of mercator. The scale bar we show on screen is calculated with respect to latitude scale, as recommended by IHO.

2. Your idea is not absurd. It is the key point.

If we know the physical size of the display, we can accurately calculate the scale.

It just remains to determine how we ask for this information from the user. Dialog box entry of dimensions in mm? Or should we ask for monitor DPI specification, which is really the same thing?

And what is default?

These are good questions, and input is good.

Dave
on this chart, O versus a tape measure on the paper chart, is spot on.
Whatever you are doing, keep it.

Then, curious to see how well WindowsXP "reports" dpi, on this screen, I used "Wonderwebware ScreenRuler" . As usual, Windows XP reports 96dpi on this 1280x720 screen.But in fact, it need 100horizontal and 94 vertical dpi to agree with an actual ruler, according to this. This does vary on different computers and using different "screen ruler" apps has agreed with the Wonderwebware one.
This screen no doubt was sold as "14" diagonally and indeed it is.

Click image for larger version

Name:	ScaleinO.jpg
Views:	56
Size:	72.7 KB
ID:	93479
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Old 12-12-2014, 09:30   #338
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Re: OpenCPN Beta Version 3.3.2330 Released

Quote:
My guess is that it will work, and that they are present to facilitate a re-projection.
To answer your question.... You can test your self, if a re-projection is possible. Check out this page
Nautical Chart Reprojector | Digital Coast
If it works, you should end up with a Mercator chart that should be OK in O.
Should this link be put in Wiki under Supplemental Software with an explanation for when it is useful?
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Old 12-12-2014, 10:34   #339
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Re: OpenCPN Beta Version 3.3.2330 Released

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Originally Posted by dacust View Post
Me neither. Intriguing.

These days I don't have time to dive in to something like this, but I'll be very interested to hear anything and everything anyone comes up with.

-dan
Dan
I'm not sure if you misunderstood me.....
Quote:
....in charts from them.
was missing from your quote. I was only talking about charts from "Solteknik".

The polynomials and ERR lines are present in every NOAA and NZ kap, for example.

from The BSB/KAP file format. | Official OpenCPN Homepage

Quote:
WPX – Polynomial longitude to x - optional. The Polynomials is an alternative to REF points for georeferencing. OpenCPN uses these polynomials if they are available. The existence of polynomials is a condition for using noaa:s chart reprojection tool.
PWX – Polynomial x to longitude - optional
WPY – Polynomial latitude to y - optional
PWY – Polynomial y to latitude - optional
ERR – Error record –These should be present if polynomials are used. These ERR rows report the error at the REF points due to the usage of polynomials.
Thomas
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Old 12-12-2014, 11:15   #340
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Re: OpenCPN Beta Version 3.3.2330 Released

Why not? I got a result on one of Hakans Charts he uploaded (HG-DEMO_1.KAP)...with the same odd header. I put in 59N as central Latitude in my reproj. (PR=59.00000)

Click image for larger version

Name:	ReprojMERCwpt.jpg
Views:	43
Size:	15.6 KB
ID:	93485Click image for larger version

Name:	TM wpt.jpg
Views:	47
Size:	16.1 KB
ID:	93487

(didn't get the TM zoom equal for straight comparison but comparison of a wpt is pretty good )
But it's going to be a lot of work to fix a lot of the TM this way.
here's the example from HG-DEMO_1.KAP (... save link as,rename/remove the ".doc" extension)
reprojected.zip.doc
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Old 12-12-2014, 20:59   #341
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Re: OpenCPN Beta Version 3.3.2330 Released

Quote:
Originally Posted by cagney View Post
Dan
I'm not sure if you misunderstood me.....

was missing from your quote. I was only talking about charts from "Solteknik".

The polynomials and ERR lines are present in every NOAA and NZ kap, for example.

from The BSB/KAP file format. | Official OpenCPN Homepage



Thomas
Thanks for the explanation. Then I should have said, I don't remember dealing with any of those in mc2bsbh. But it's been a coupla years since I looked at that code.

-dan
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Old 13-12-2014, 07:30   #342
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Re: OpenCPN Beta Version 3.3.2330 Released

Quote:
Originally Posted by bdbcat View Post
Gilletarom...

1. Mercator projection: On paper charts, distances measured manually with dividers are converted to actual distances using the latitude scale. This is normal navigation practice. Of course, at high latitude, there will be distortion, horizontal vs vertical. This is the nature of mercator. The scale bar we show on screen is calculated with respect to latitude scale, as recommended by IHO.

2. Your idea is not absurd. It is the key point.

If we know the physical size of the display, we can accurately calculate the scale.

It just remains to determine how we ask for this information from the user. Dialog box entry of dimensions in mm? Or should we ask for monitor DPI specification, which is really the same thing?

And what is default?

These are good questions, and input is good.

Dave
I investigated how it is done in the screen measuring app I use
Meazure
Ultimately, to get a correct value in cm/inches, the user must calibrate a line with a ruler on his screen !
I suggest such a calibration procedure be put in the advanced part of the option / display section
Possibly, let the user measure a line made of a given number of dots with a ruler, and enter the length in cm, mm or inches.
The chart scale would then display a small U following the scale value for Uncalibrated, or a C for Calibrated

PS On my screen a purported 25000 scale is actually about 34 000...
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Old 13-12-2014, 08:37   #343
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Re: OpenCPN Beta Version 3.3.2330 Released

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Originally Posted by wdkester View Post
Can't seem to find "Lock Waypoints". It used to be on the Options>Display page. It's nice to unlock WP when creating routes.
ooops found it - Options>Display>Advanced page
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Old 13-12-2014, 08:44   #344
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Re: OpenCPN Beta Version 3.3.2330 Released

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Originally Posted by wdkester View Post
While testing the function keys (F5, F6) I got the following strange result for the right click context menu.

I did a reinstall and it doesn't go away. Is there anything to do (say in the ini file) to reset this?
"Fixed" by deleting the ini file. But then I had problems with old Chart directories (that no longer existed) appearing in the directory list??????? Apparently the ini file isn't the only place chart files are remembered.
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Old 13-12-2014, 20:40   #345
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Re: OpenCPN Beta Version 3.3.2330 Released

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Originally Posted by bdbcat View Post
...If we know the physical size of the display, we can accurately calculate the scale.

It just remains to determine how we ask for this information from the user. Dialog box entry of dimensions in mm? Or should we ask for monitor DPI specification, which is really the same thing?

And what is default?
FWIW, I think that the best way to ask for the information is via manual DPI entry in the Options-Display-Advanced screen. Advanced users will know the DPI resolution of their displays, or will know how to measure it. I'll leave it up to you to decide if you'd prefer DPcm, for our European friends.

From another message that someone posted, it sounds like there may still be some displays out there with rectangular pixels, so you may need to ask for two values - vertical DPI and horizontal DPI, and scale the display differently in each dimension.

As for default, I would make it default to the DPI that the monitor reports to the OS (if, in fact, that is supported by the OS that's in use), or 96 dpi if no other number is available. Any manual input then overrides the value, making it persistent. This could create issues for those of us who use a portable installation on multiple machines (with different DPI), but those users will be advanced enough to anticipate the problem and re-enter the DPI accordingly for the different systems. You can't make the program anticipate every single possible hardware difference, and adding the option of manual DPI entry gives advanced users a powerful tool to scale their charts exactly to their liking.
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