Charts

[sinbad7]

I think my main problem all along has been the use of Notepad creating the header file. No corruption of the text itself but whatever you name/re-name the file, it will always have a .txt appendage. In Vista,this is invisible and only using Dan's automatic heading creator or a hex editor will the file have the desired appendage. Vista has several unexpected idiosyncrasies.

[GPS-Marco]

Originally Posted by sinbad7

I think my main problem all along has been the use of Notepad creating the header file. No corruption of the text itself but whatever you name/re-name the file, it will always have a .txt appendage. In Vista,this is invisible and only using Dan's automatic heading creator or a hex editor will the file have the desired appendage. Vista has several unexpected idiosyncrasies.

Never used Vista. But the "hide extension" funcion is available also in XP.

Anyway, here is how to disabele it in Vista:

Vista: Show or Unhide File Extensions | Microsoft Vista | Tech-Recipes

Ciao, Marco.

[sinbad7]

I have just completed the conversion of a North Atlantic map using Dan/Marco's utility from MapCal II. A similar map of the Pacific will follow shortly. Size 16MB so let me know where to upload

tore@yachtmarine.com

Marco. Thanks for the file type tip

[sinbad7]

And now also the Pacific if anybody is interested. Approx 6.6 MB.

[idpnd]

Who owns these charts? Could they (or similar ones) not be used to make up a standard/default opencpn world chart?

[sinbad7]

The two oceanic charts sampled here are produced by the US Mapping service which are public domain I believe.

[cagney]

Originally Posted by sinbad7

And now also the Pacific if anybody is interested. Approx 6.6 MB.

This is INT51 aka NZ14051 available as tif here http://charts.linz.govt.nz/tifs/nz14051.tif
This chart does not show up in the LINZ website interface but is available nevertheless.

Thomas

[cagney]

Originally Posted by sinbad7

I think my main problem all along has been the use of Notepad creating the header file. No corruption of the text itself but whatever you name/re-name the file, it will always have a .txt appendage. In Vista,this is invisible and only using Dan's automatic heading creator or a hex editor will the file have the desired appendage. Vista has several unexpected idiosyncrasies.

I doesn't matter for libbsb what file extension you use for the template file. The .txt is just fine, if that keeps Vista happy.

Thomas

[sinbad7]

Thomas..

Yes I realize the extension is immaterial in tif2bsb template file,but I was naming it .kap whilst the REAL file name was .txt,and that was not acceptable.

Interesting observation in the Solent a few minutes ago. MS Queen Victoria outward bound for Barcelona.

[cagney]

Sinbad

Big difference in size between your Atlantic and your Pacific charts!
Is there maybe some missing tif-compression missing in the Atlantic one?
My NZ14051 is about 5.1 mb.

Thomas

[idpnd]

Originally Posted by sinbad7

The two oceanic charts sampled here are produced by the US Mapping service which are public domain I believe.

Lovely stuff! I do feel the main opencpn image should be a nautical chart as well, how could this be implemented?

Edit: I just spotted that one is an overview map pointing to smaller charts, whilst the other seems to be simply a large-scale map? Where do you source these overview maps please?

[sinbad7]

Thomas..

The North Atlantic chart has also been compressed and has a 96 dpi.

Having access to some 7000 AIS targets,I notice the calibration is out by some 460 nm to the South. I took all the calibration data from cm93 in OpenCPN and even did it twice but it is still way out. Any ideas why?

[sinbad7]

Edit: I just spotted that one is an overview map pointing to smaller charts, whilst the other seems to be simply a large-scale map? Where do you source these overview maps please?

I am not sure which overview chart you are referring to?

You will get all of the maps here I think:

[cagney]

Originally Posted by sinbad7

Thomas..

The North Atlantic chart has also been compressed and has a 96 dpi.

Having access to some 7000 AIS targets,I notice the calibration is out by some 460 nm to the South. I took all the calibration data from cm93 in OpenCPN and even did it twice but it is still way out. Any ideas why?

The chart is way off. I get 900 miles lat error at the equator.
Use the corners, looks correct in the MapCal file, as PLY:S
You have to use the same points as REF:s to give the algorithms in OpenCPN
a fair chance. This is also required in the new algorithm, that only
uses the four corners and then mathematically calculates the rest if,
and only if, the scale is 1:5.000.000 or less.

Why aren't the corners in the MapCal file used as PLY:s?
PLY 2 and 3 have lat:s outside the chart !! ++

For small scale charts down to 1:5.000.000 I would pick 6 -8 evenly
spread out latitudes and longitudes, maybe every even 5 or 10 degrees,
and then use all the intersections as REF:s in a "serpentine" pattern.
I have done this with quite a few Pacific charts, and struggled to get them as accurate as possible.
I have often seen this or similar strategies in commercial BSB charts. REFs is more than just picking a few random spots on the charts.

Thomas

[sinbad7]

Thomas..

As you suggested,I changed the calibration to read only the four corners of the map for both the REF and the PLY and it now seems more correct.

Why is the map path now colored orange?