S63 charts - overzoom

[bcn]

Playing with the chart and Google in an overlay using the Lat/Lon grid of the two sources I doubt that the chart or it's datum has been the reason for grounding.

But perhaps we will know one day.

[bcn]

Seems it might have to do something with zooming - but in a different way:

Yann Riou
OBR, Dongfeng Race Team
Go to team website
“Beautiful islands in the middle of nowhere, but right in the middle of our route!” (Charles)
That was the reflection of Charles Caudrelier just after passing the Cargados archipelago. Shortly after we gybed, a bit later than our closest rivals, right at the time of the big wind shift, but without anticipating that this shift would be so strong that it would take us onto a direct route to the island.
A little moment of hesitation during which we asked which side we should pass.
“A small navigation error which cost us two to three miles.” It could have been worse.
Charles had noticed this archipelago a few days ago. But it’s worth noting that it’s actually pretty hard to find. In fact, to see it on our electronic charts, you have to zoom right in on top of it. But how and why would you zoom into it if you don’t know it’s there in the first place?
So whilst we don’t know exactly what happened on Vestas, we can imagine how it happened. In any case it’s been a big shock for us to hear the news. It’s still hard to believe it happened.
At least no-one was hurt. But for sure it’s a very bad news. For Vestas and the race.

[bcn]

(OT) And a photo:

[LeaseOnLife]

Originally Posted by bcn

(OT) And a photo:

where did you snag that pic?

I posted this is another thread:
http://www.cruisersforum.com/forums/...ml#post1689331

Latest position of Team Vesta:
http://www.volvooceanrace.com/static...eg02_00089.txt

16-48.30S
59-34.53E



I hope to learn how this happened.

Dirk

[LeaseOnLife]

Originally Posted by cagney

...

PS Anyone using CM93 for navigation should have a look att Cargagos Carajos.

Navionics isn't any better, surprise, surprise:

when not zoomed in enough, you barely see a shoal, but no reef. One zoom level further in, the reef is shown.

I love raster charts, even NGA-702 "Chagos to Madagascar" clearly shows the reef.

NGA Chart 702 Chagos Archipelago to Madagascar


One good feature of OpenCPN are the chart outlines, at least the user is warned about more info is available when zooming in.

But do the chart outlines work for vector charts? I can't seem to make them show...


Dirk

[cagney]

Originally Posted by bcn

Seems it might have to do something with zooming - but in a different way:

OpenCPN has exactly the same problem when using CM93 in quilt mode.

There is quite a bit about the limitations of CM93 in the manual.
Let's hope that new users actually read those pieces.........

Thomas

PS
Anyone knows what charts/program they used?
If the had used O + S63 charts + outlines activated, they would have known of the existence of a larger scale chart.

[LeaseOnLife]

Originally Posted by cagney

OpenCPN has exactly the same problem when using CM93 in quilt mode.

There is quite a bit about the limitations of CM93 in the manual.
Let's hope that new users actually read those pieces.........

Thomas

PS
Anyone knows what charts/program they used?
If the had used O + S63 charts + outlines activated, they would have known of the existence of a larger scale chart.

Thanks Thomas, from the manual http://opencpn.org/ocpn/chart_quilting :


The exception to the last rule is CM93 charts. When an area is only covered by CM93 charts, indicated by a long yellow chart button in the status bar, and in quilting mode, no info-box is displayed and no reddish highlighting is taking place.

When CM93 quilting is off, the outline of the individual cells are outlined in magenta.

While it is described in the manual, that doesn't make it 'right'. Is it too hard to display the chart outlines with quilted CM93?

Dirk

[bdbcat]

Dirk...

Its not hard, but does not give much information except in the types of cases under discussion. (small atoll in open sea, i.e. one larger scale chart floating in a small scale sea). Usually, you would see just a cluttered mush of larger scale cell outlines overlayed on a smaller scale display. We elected to not show this in the interest of clarity.

But we can certainly talk about it again, and maybe come up with a useful display.

Dave

[bcn]

Originally Posted by LeaseOnLife

where did you snag that pic?

I posted this is another thread:
http://www.cruisersforum.com/forums/...ml#post1689331

Latest position of Team Vesta:
http://www.volvooceanrace.com/static...eg02_00089.txt

16-48.30S
59-34.53E



I hope to learn how this happened.

Dirk

From the Spanish version of their official site.

And if you watch the video with the declarations you will see how they ran directly into the atoll.

On this screen we might see the GPS track, so it is south east of the light house and not west as Thomas suspected.

[bcn]

Originally Posted by cagney

OpenCPN has exactly the same problem when using CM93 in quilt mode.

There is quite a bit about the limitations of CM93 in the manual.
Let's hope that new users actually read those pieces.........

Thomas

PS
Anyone knows what charts/program they used?
If the had used O + S63 charts + outlines activated, they would have known of the existence of a larger scale chart.

What would be handy for route planning would be an automatic check for hazards on the route (ECDIS do have this - this includes a safety contour and safe draft). For vector charts only obviously.
For raster this might be a bit more challenging! Sean??

Hubert