CM93 File region codes

[Moontide]

I have spaced on the way to interpert the CM93 region codes on the files. Must be an age thing. I seem to recall that they start at the south pole and work north, but I don't remember enough details to decode them. Here is an example of what I am looking at.

003300120

I know that breaks down to tell me the lat / long fo the area that chart group covers, but . . . .

Am sure it is very simple so please don't laugh too hard at this.

Bill

[.Paul.]

Bill,

The CM93 folder and file numbering convention is noted in the OpenCPN manual:

https://opencpn.org/wiki/dokuwiki/do...hart_files_tab

You will see the "CM93 Charts" heading near the bottom of the web page. As of the date of this reply, it reads:

CM93-version2 Charts are different from the S57 vector charts, and has it's own data structure consisting of a number of folders and files. To load these charts in OpenCPN just add the top directory to the list of “Active Chart Directories”.

In the top CM93 directory is an empty file with the “.EXD”, for example 20110803.EXD. The format is YYYYMMDD.EXD. This is the version, or edition, of the CM93 -v2 release.

OpenCPN supports partial CM93 datasets, covering one or a few of the available regions. There is also support for multiple, as well as multiple partial, CM93 datasets.

The CM93 top directory contains a number of (144) subdirectories named from “00300000” to “04501020”, as well as six other files. These sub directories each cover a geographical area of 40° x 40° . The first four numbers describes the latitude and the last four, the longitude of the SW corner of the area covered.

There may be more detailed information elsewhere in the OpenCPN manual, but I could not find more at this time.

Paul

[Moontide]

Thanks Paul. Exactlyu what I was looking for. Could load all the CM93 files in but really slows down OpenCPN. Think I'll add a README file to my CM93 directory.

Bill