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doublebubble · 05-10-2021, 22:50

Hi guys, been using Opencpn for a few years now cruising Australia but the charts from the O shop for Australia are lacking a lot of detail, are there any other types of charts for Australia that show more detail? What other types, kinds of charts could I use, CM93v2 I would like but have no idea on where I can download them from, googling hasn't come up with much, any pointers would be appreciated.

Cheers Rod

yachtvalhalla · 07-10-2021, 17:18

Quote:

Originally Posted by doublebubble

Cheers Rod

Sent you a PM.

Terry

Reefmagnet · 07-10-2021, 17:38

I had the O shop charts and the CM93 and they seemed pretty close detail wise. AFAIK they are derived from the official Aus Hydrographic charts. Are you sure you've got your chart settings in OpenCPN set to display the information you require?

doublebubble · 07-10-2021, 18:02

Cheers Reefmagnet, I'm pretty sure that I have the settings correct but I'm open to know if I don't �� if there is area to read or some advice on settings would give me the highest standard of information/detail that would be great, one thing that I notice is when I'm zoomed in there is is quite a lack of soundings on the chart.

doublebubble · 07-10-2021, 18:10

Quote:

Originally Posted by yachtvalhalla

Sent you a PM.

Terry

Thanks Terry, much appreciated.

Cheers Rod.

Jon Hacking · 07-10-2021, 18:11

Quote:

Originally Posted by doublebubble

Hi guys, ... the charts from the O shop for Australia are lacking a lot of detail, are there any other types of charts for Australia that show more detail? What other types, kinds of charts could I use, ... any pointers would be appreciated. Cheers Rod

Rod, CM93 charts are not known for having much detail unless you're in fairly populated & well traveled waters. They're OK along much of the QLD coast, but if you're planning to go to more remote areas, detail & accuracy drop off significantly. They're also still a CMap product, even though they haven't been updated since 2011, so folks are cagey about posting them online.

Because of this, we've been making our own extremely accurate & detailed charts, using SAS Planet & Sat2Chart. The tools & data are all free on the internet, but it does take a lot of time, internet data, & a Windows computer. The charts themselves can be used on any computer that runs OpenCPN, but the tools to make the charts only run on Windows.

The available chart data currently includes Navionics & CMap marine charts, which are reasonably accurate & have depths. But we actually prefer the satellite imagery from ArcGIS, Bing (MSFT), Google Earth, Nokia, etc. These are amazingly accurate, with max errors on the order of 3m. Superb geo-registration, & they show near-shore reefs & shallows, including the GBR. They don't show everything, but where they show something, that's exactly where it is.

We've recently put together a How-To page on Making mbTiles, which is a chart file format that OpenCPN has been able to use for a couple of years, since v5. It's written so even a novice can make high-quality navigational charts, & we also show you how to use the automation provided by Sat2Chart to get your computer to do the hard work while you sleep (or do something else).

The page is only a few months old, so we encourage folks with questions to contact us. The only silly question is the one not asked, & if you have questions, it's a sure bet that others will have the same question, & we'd like to address those in the page itself.

Good luck!

**StuM** · 07-10-2021, 19:40

It's worth noting that the most recent CM93V2 charts available around the intertubes are generally about 10 years old. Reefs don't move much, but nav aids and man made structures do

Also, I've' found that in general where the O-chart Aus/PNG charts are lacking in detail, CM93 is as well.

Jon Hacking · 07-10-2021, 20:11

Quote:

Originally Posted by StuM

It's worth noting that the most recent CM93V2 charts available around the intertubes are generally about 10 years old. Reefs don't move much, but nav aids and man made structures do

Also, I've' found that in general where the O-chart Aus/PNG charts are lacking in detail, CM93 is as well.

I don't think CM93v2 has been updated since about Jan 2011, when they came out with their encrypted V3 charts & dropped their V2 efforts.

It seems that they tried to keep their V2 chart database to 1.4GB, which meant that when some charts were updated, others were dropped. When we went through Chagos (a delightful bit of magic in the middle of the Indian) in 2007, CM93 was offset by about 100m, which was fairly standard. The 2009 charts corrected the offset, but also removed the chartlet for the shallow entrance to Salomon Atoll! Frustrating.

One way to correct this is to start with an old CM93 database (say, 2005 or so) & then copy new databases on top of it, in date order. This would update (overwrite) any corrected charts, while leaving intact any charts that were left out in later releases.

We use such a hybrid version of CM93, thanks to s/v Perry. Instead of the normal 24K files in 1.4GB, it's 27K files in 1.8GB.

**StuM** · 08-10-2021, 00:21

Quote:

Originally Posted by Jon Hacking

We use such a hybrid version of CM93, thanks to s/v Perry. Instead of the normal 24K files in 1.4GB, it's 27K files in 1.8GB.

Hmmm, mine's 2.57GB - 38 035 files in 1553 folders.

The root contains the file 20110803.EXD (supposedly 3 Aug 2011) but that file has a file date of 3 Dec 2003 so it's clearly been renamed ( there is another file SERIALNO.TXT with the same 2003 date )

)

Most of the data files are dated Jan 2011, but there are quite a few older ones dating back to 2008

yachtvalhalla · 08-10-2021, 01:45

The latest version I have is 2015, 30,401 Files, 1,710 Folders. 20150505.EXD

But some detailed areas in Asia have been removed compared with the 2007 version.

Terry