Charts on CD

[cagney]

Originally Posted by Jammer Six

"A mariner operating on an uncorrected chart is courting disaster."

Bowditch, LL.D., Nathanial, ed. The American Practical Navigator. Bethesda, Maryland: NATIONAL IMAGERY AND MAPPING AGENCY, 2002. s.v. "Using Charts., page 49"

I've never understood why someone would buy an old, uncorrected chart, particularly one that can't be corrected.

Jammer

You are "jammed" on correcting charts.
Just for fun, find out when the US chart for Pitcairn Island was last updated.
Who said that a raster charts could not be updated? Ever heard of Gimp or Photoshop?

Some very good navigators don't even know what a chart is. Ever heard of old time Polynesian or Arab navigation?
Others made their own as they went along. Ever heard of James Cook?

No chart is ever "correct", whether updated or not. Just adjust your navigation accordingly.

Thomas

[Jammer Six]

That's what I like to see. Folks arguing with Bowditch.

[Helmsmatt]

LOL,
Bowditch, no, we're arguing with you

[osirissail]

Not to "pile on" but it is too much fun to resist - apologies. Having researched the subject of nautical echarts and "updating/revisions" extensively over the years, it is very true as stated by others that there has been no, or at most, very minimal "updating" of any nautical charts since WWII or earlier.

What has been updated when speaking of NOAA RNC's and others in their chart folio has been the commercial harbors and waterways in use by major shipping. And even that has been restricted to channels and marker/buoy data.

When I spoke personally to NOAA rep's at a major boatshow and complained about the gross errors in some of their charts both topographically and hydrographically - they replied that there has not been any money in their budgets to do anything beyond trying to keep up with major commercial traffic areas and channel markers. They even stated that it has been 40 to 50 years now.

From the NOAA website where you can download for free the library of RNC's and other charts, there is a notice you must acknowledge which contains the following: "While NOAA has accuracy standards for each step in the data collection and chart production process, much of the depth information found on NOAA charts is based on surveys conducted before 1940, the shoreline is more than 20 years old, and paper charts used to be compiled manually. For more information regarding the accuracy of electronic charts, click here."

Companies and other outfits selling electronic charts compile and sometimes convert existing libraries of freely available charts to their special format (so you cannot copy their disks) and sell them as "updated" charts. What has been "updated" is those few and far between commercial harbors/waterways I mentioned above. Other than those the rest of the chart package is merely copies of old charts.

No company/agency in their right legal minds would alter/update any charts beyond what the controlling governmental agency (like NOAA) has done. To do so would transfer to them the legal liability for errors. Also they almost always attach a statement to their chart package warning that these charts are "Not for Navigation" (used as a primary navigation source).

So trading or collecting old e-charts from sources no longer in business is fine and the charts are as accurate as any you will find elsewhere, with the above mentioned exceptions. Those repackaging selling NOAA charts cannot "copyright" them - but they can copyright their "format" for storing and displaying the charts. Which is why you have BSB version 4, and higher - the lower versions cannot be copyrighted as NOAA uses them. Remember NOAA only does charts of the USA and its territories.

As to actually anybody "updating/revising" any charts of areas outside the USA, I know of only the French and British Admiralty that actually really update/revise charts. Maybe the Aussies and some others also but the vast majority merely copy existing old charts, "warts and all."

As to us little guys, sailor/cruisers, it is rare that geographical and hydrographical features have changed in the last century except for places where tectonic activity or bulldozers have changed things.

The major sources of errors in nautical charts comes from trying to standardize the "DATUM's" each chart was made with originally to the WGS84 datum used by most GPS systems. If the chart has not been "re-registered" to WGS-84 it is likely that the position of your "little boat symbol" will be different from what you observe visually in real life. This displayed "boat position error" can be minor or off by "miles" - literally. However, the chart's topographical/hydrographical representation is probably still quite good - you just have to ignore any Lat/Long references.

Almost all nautical charting programs have some way to add notes or symbols and notes to the displayed chart. So "you" can update/revise the chart yourself when you encounter an error or missing feature. And actuality this is how master mariners handled their charts in the old "paper" days. They transferred by pen or pencil the revised data and then noted in the corner of the paper chart the date and who did the revision.

So don't get "snookered" into thinking you have to buy the latest "updated" version thinking that somebody has actually done revisions to the charts beyond governmental agencies. You can still use the "old" charts and do your own revisions with your charting program.

[osirissail]

Originally Posted by Helmsmatt

Thanks for your reply.
You said:
the old chart disks were organized with folders as the examples I cited showed. And along with the top folder titled "Charthdr" were additional folders named as the examples I cited - one folder for each map named in the "Charthdr" folder.

My disk has the charthdr folder, and the accompanying small chart folders with the multiple bits .a01, etc.
Also the mworlds are there too.
I believe I have the proper .hdr format data to do the conversion. They are old Maptech disks, I believe.
Just need some help in the procedure.
Thanks again,
Matt

The procedure is to use an "old" charting system that does not do "stitching" and/or has deliberately not included the code necessary to reassemble the old Maptech "charthdr" format. In my experience those charting systems include The Capn up to version 6 (maybe 7) and old Nobeltec - prior to 2004 versions. As I mentioned reassembling the dozens, if not hundreds of chart fragment data into a single chart for display requires a lot of computer memory.

You can only try referencing your library of these old charts in your current "raster" charting program and see if it will accept the files. If not, then you have to get and install one of the "old" chart navigation systems in order to utilize these old Maptech charts. Good luck.

[Helmsmatt]

Yeah,
Not quite the answer I'm looking for.
I do have an old version of the Cap'n that can read the .hdr charts, but it doesn't allow AIS, Garmin radar, grib file viewer, dashboard, etc.
OCPN has turned into likely the best Nav program out there, and I include the dedicated MFDs, as there is no better routing tool than a PC with a mouse or touchpad.
We are still working with Cagney's conversion scripts to try to convert and are studying the chartsII thread. Wife, Cindy, retired S/W Engineer, has taken over this effort. I'm sure she'll have good results, but I can hear the frustration quietly emanating from the Nav station as I type this.....
Wish there was a script or app out there that was easy to use......
Matt

[dacust]

Can someone post some examples of the hdr files? Are they plain text? I think Thomas already has a script to assemble the tiles...

-dan

[Helmsmatt]

I have some old maptech .hdr cds.
They aren't text, but an array of small .pcx files, as I'm told, with a HDR directory followed by chart directories containing for example files M####.A01, to M####.L12. We've tried to follow Thomas Cagney's posted scripts to assemble the tiles, but neither I nor Software Engineer wife have been successful. I've seen your efforts on the 2700 NG charts thread, and was likely not as frustrated as you with the result. I found 74 odd charts, mostly of Africa, but I'm not headed there any time soon. I'm very interested in Region 2, Caribbean, central and S. America....
Thanks for listening,
Matt

[Jammer Six]

Updating a paper chart is the responsibility of the owner.

[osirissail]

Originally Posted by dacust

Can someone post some examples of the hdr files? Are they plain text? I think Thomas already has a script to assemble the tiles...
-dan

A straight dump to Notepad of a chart #124 "charthdr" file gets:
ž˜P 0005281950North Atlantic Ocean - Southwestern Sheet M00124S0 06/15/9610 NIMA €àK12 q�EYdHûä¥E0ñDbÓEö~zÂUxŸEuÔE12/01/99 €? €?

The 132 files of the pieces of chart #124 add up to 5.91MB - that's for the one single chart.
A straight dump to Notepad of one of those 132 files that make up chart #124 pieces averages 36 KB to 123 KB of code and looks like (just a small section so that this post doesn't go on for pages and pages):

߀à ÚÚÚ´´´{{{KKKÞîý*Î÷‚œ»9sÖ)œsÝúëk91Ŭڀ\ K1^ÿÿÿ P ÿÿÑÿÿÿÑÿÿÿÑÿÿÿÐÿÁÿÿÿÑÿÿÿÑÿÿÿÑÿÿÿÐÿÁÿÿÿÑÿÿÿÑÿÿÿÑÿÿÿ ÐÿÁÿÿÿÑÿÿÿÑÿÿÿÑÿòÿÁÿ ÁáÁÿÁÿÁáÁýÁðÄÿÁÿ‡ÁÿÌÿÁÿòÿÁÿ ÁáÁÿÁÿÁáÁýÁðÄÿÁÿ‡ÁÿÍÿòÿÁÿ ÁáÁÿÁÿÁáÁýÁðÄÿÁÿ‡ÁÿÍÿòÿÁÿ

So I can understand the frustration of "Helmsmatt" s/w friend trying to write a display script.

I used to use "Fugawi" until I lost the key code that let me migrate it from one computer to another after a computer fatally crashed. It had a side program that would convert a "pcx" or similar type graphic file into a registered nautical echart. I used it several times to convert guide book sketch charts, etc. into usable echarts that would display on my Capn 6 system.

[cagney]

The basic idea in my script still works. I think that the problem lies in the different naming convention use by different chart makers.
It was a long time since I had a look last time. No itch to scratch anymore. I have not come across any hdr chart that I have failed to convert, and still have quite a few available. I have not used a mega advanced computer with a lot of memory for conversion.
An hdr-chart consist of a lot of pcx tiles, and a small binary file with some clear-text. This file normaly has a .hdr extension and a name corresponding to the name of the directory containing the pcx tiles. My script assembles the pcx files to one picture that has to be converted to a kap chart with a well documented procedure.

Having said all that, there are probably better ways available. I do think that this has been discussed in threads on this forum after I published the script. "Happy Seagull" pointed out that "xnview" ,http://www.xnview.com/ , is capable of performing the task. I have not tried this myself.



Thomas

[Helmsmatt]

Thanks for the reply, Thomas,
I saw the huge effort on the 2700 NG chart thread that ended poorly. I hear that this might open up a bit.
Cindy did a bunch of research, and realized that your script was meant for Linux.
We're running Win7.
I think she's given up....
Matt

[cagney]

Originally Posted by Helmsmatt

Thanks for the reply, Thomas,
I saw the huge effort on the 2700 NG chart thread that ended poorly. I hear that this might open up a bit.
Cindy did a bunch of research, and realized that your script was meant for Linux.
We're running Win7.
I think she's given up....
Matt

Yes the script is a shell-scrip but it's only using imagemagic that is available for windows. A person that's into windows scripting should be able to produce a Win version.
What about xnview? Has anyone tried? Any good?

Thomas

[Helmsmatt]

Haven't tried xnview yet. Maybe tomorrow. Cindy is done going down the PC rathole today :-)
Matt