Northwest Caribbean Charts

[Jenda]

Looking for opinions from people, who had the chance to run side by side Navionics, Garmin, possibly other two dimensional electronic charts systems around Mexico and Belize (Guatemala, Honduras) coast. Also, is CM93 v3 going to be any better than CM93 v2 in this area? CM93 v2 looks pretty spotty to me, but the coverage by paper charts is reportedly not much better there.

How reliable are the drawings which come with Freya Rauscher's guide? Is it worth of georeferencing them and getting them on the screen, or shall I just dust of my old Yeoman? I will be mostly singlehanding, so not having much time to plot on paper.

Would satelite images work well for the area? It does not look too bad in Google, but are Garmin satelite images going to be as good? (Do not have Garmin plotter at hand to try, and they say that resolution varies.)

What worked for you?

Thanks in advance for your observations and any ideas. Also would appreciate any links to sources of info on the subject.

[colemj]

We have CM93 v2 and the newest CMap charts of this area and have never seen a single difference between them from Panama to Belize. They have very poor coverage in Honduras and Belize. Navionics on our iPod has much better coverage, so I would think that the full Navionics would be even better. No experience with Garmin charts. Georeferencing Rauscher's charts would be no less helpful than the CMap charts, and possibly more helpful. Satellite works for some areas, but not others. For example, the Hobbies and Barcareo's do not show up at all on Google Earth, while the Vivirellos is poorly shown.

Mark

[belizesailor]

Yeah, CMAP generally stinks for the region. Especially Belize. The version I have (updated a few years ago) has good detailed coverage for the Bay Islands for some odd reason, but Belize is still a joke.

Of the electronic charts Ive used in the region, Ive found Navionics to be pretty good.

Re Google Earth. Some of the coastal imagery for the region is not very good....southern Belize reef for example. Certainly not enough detail to navigate by in most places. I run Fugawi on my laptop and it has a cool feature that allows you to overlay chart and Google Earth data. This is good for verifying chart versus satellite image for areas with good imagery. You can also scan and georeference paper charts which is handy (like the ones below).

The best nav info (electronic or not) for Belize is Freya Raucher's excellent cruising guide. The "Rains Guide" is also quite good for typical transit routes (but not a cruising guide per se) through the W Carib.

[belizesailor]

And re dusting off the old Yeoman. Note that many paper charts of the region (esp Belize) are still based upon British surveys from the late 1800s. Considering the technology of that era, some of these surveys were impressively accurate....some not so much. Most of the gov't issue paper charts are still based on this data.

By contrast, very few inaccuracies in Freyas charts.

One of the few areas in Belize with recent survey data is around Belize City. This is because of commercial traffic there.

[belizesailor]

More on CMAP. Just recalled that I did test out CMAP using the Jeppesen Plan2Nav app on my Samsung tablet recently. Have not used it a lot yet, but on a couple of short runs in Belize, it appears to be better than the cartridge based (a few years old) on my chart plotter. There are still some irregular rectangle islands and lack of detail in some areas (Navionics is better on both counts), but better than the version from just a few years back (which was a bad joke).

[wdkester]

I scanned in Freya's chart for beleize. the northern part was OK. The southern part was not good. This may have been due to the scanner skewing the paper as it fed it in. Freya's way points were good. I made some GE charts and used them on OpenCPN.

[bcn]

This side gives an idea if the actual situation for official ENC (Electronical Nautical Charts aka Vector charts):

" + theTitle + "

(if the map does not open try with a less wide window)

It shows for that zone some charts with dates from 2010 on.
Does not mean that those are available from commercial vendors, but there is at least the base.

[Jenda]

I do not understand what this is actually supposed to do. To actually see a chart? I am getting outlines only. Thanks.

[bcn]

Hi Jenda,

no, you won't see the content of the chart - it does not solve your issue to get charts for the region.

But you can get an idea what base material does exist.
If you use the "i" button and select the type of charts at the right side of the window then clicking on a outline of a chart will bring up something like:
GB389310 90000 Coastal Gulf of Honduras IC-ENC 5 Tue, 15 Jan 2013 00:00:00
So at best you can this from a chart supplier. As electronic or paper chart.
In this case Admiralty would be a provider for that chart.

[Jenda]

Thanks. Nice, but pretty much useless, is it?

Anybody out there, who managed to download the NGA, DMA, or whatever the name of the outfit is, charts for this area before they pulled them? I have a serious doubt, that anybody would bother to enforce their highly questionable copyrights. They have bigger fishes to fry

[belizesailor]

Originally Posted by wdkester

I scanned in Freya's chart for beleize. the northern part was OK. The southern part was not good. This may have been due to the scanner skewing the paper as it fed it in. Freya's way points were good. I made some GE charts and used them on OpenCPN.

A scanner or georeferencing issue. The size of the charts and the fact that they are normally folded (making creases) makes them a challenge to georeference accurately. I've had better success scanning smaller sections with a flat bed scanner.

The charts themselves are quite good. I've used them all over Belize for many years and only found a few omissions and one route I don't advise.

[Jenda]

Well, would you please tell us, what route it is - you do not advise:-)

As for scanning, what seem to work for me, is to take one picture of each half of a standard size chart with a 24 Mpixel camera and stitch the two halfs together in photoshop or gimp, take care of better contrast, straighten the edges etc. One can do it on the go, no need to lag a scanner behind.

The Rauscher charts should be easy this way. To get rid of the creases, I had copies made at Staples (they make them pretty flat) and destroyed the originals, not to insult anybody's copyright at $7.00 worth. I could have ironed them out, but an iron costs more than the copy job.

My problem is with georeferencing - finding some simple routine similar to the one in Yeoman, but on the PC screen, of course. It is hard to believe, that somebody has not written something of this kind yet.

[wdkester]

I don't have them anymore so I can't really can't go back and look. The charts that I'm talking about are the large foldout ones. I scanned the one that had the south half of belize and glover is. in with a giant Kinkos scanner'. It is skewed to begin with so I rotated it with some graphics s/w so that north was up, and then georeferenced it using the coordinates on the chart. Lots of room for error on my part. Those large charts are clearly hand drawn and I suppose were not intended to be scanned in and used in a chart plotter.

I'm wondering if you scanned in the same chart, or parts of it, and found it accurate?

I should add that the smaller sketch charts that I used were reasonably accurate.

[colemj]

Originally Posted by Jenda

My problem is with georeferencing - finding some simple routine similar to the one in Yeoman, but on the PC screen, of course. It is hard to believe, that somebody has not written something of this kind yet.

SeaClear - been around for ages.

Mark

[Jenda]

David, it would be very nice of you, if you could send me the smaller charts too. No, unfortunately I did not have time to check out anything yet, but I will. Trying to gather what the options are first.

Mark, I have heard of Seaclear and will try it, but I also heard, that it is not overly user friendly. What discouraged me a bit was, that the author does not seem to support it anymore, or at least there was no recent development according to the web site, so I was paying more attention to opencpn. Needless to say, I am more interested in sailing than in improving my computer skills right now (After 10 years building the boat).

Thanks to all who responded.