Strange Symbols, Raymarine Chartplotter

[pete33458]

I have a Raymarine 435i. There are two things I just don't understand. First, there is this rectangular grid of little pink birds (no, I'm not making this up), what the heck are those? Second, many of the soundings will have a smaller number to the lower right, usually an 8, but sometimes a 7 or a 9. They can't possibly be other units of measure, because you can't have a 10 foot depth convert to 8 meters or fathoms... Any insights into either of these great mysteries? I've searched the Raymarine literature and the web to no avail, been bothering me for years... pete

[promax]

Pink flamingos

[pete33458]

Originally Posted by promax

Pink flamingos

They could be pink buzzards, I just want to know why they are there.

[promax]

I have a raymarine plotter and have never seen those symbols, sorry Possible they represent an obstruction of some sort Compare the area to a paper chart

[Lost Horizons]

These are the features of certain versions of Navionics charts. My Raymarine C80 does not show them, but the iPhone does.

The soundings figures are the decimals and they are actually very accurate numbers. Some areas have different markings than flamingos. My guess is that it defines protected areas, but I don't know for sure.

[jackdale]

Do your pink birds look like this?



If so, they are "Limit of restricted area".

The subscript numbers are likely 1/10 of depths. Is your chart plotter set for metric (SI) depths? Fathoms and feet would always be 5 or less.

Jack

[pete33458]

Originally Posted by jackdale

Do your pink birds look like this?



If so, they are "Limit of restricted area".

The subscript numbers are likely 1/10 of depths. Is your chart plotter set for metric (SI) depths? Fathoms and feet would always be 5 or less.

Jack

Jack: with respect to the first part, yes, and restricted area makes sense where i normally sail (Florida Keys = coral).

In the second part (also a response to Lost Horizons), I had considered that it might be inches or tenths of feet, EXCEPT...that it would seem to me that if it were tenths of depths, it wouldn't almost always be an 8, but rather, an even distribution of all numbers between 0 and 9. So I don't think this can be the case. pete

[Lost Horizons]

The decimals there do have a strange distribution, but except .8 I have seen other numbers as well. In the following image, which is a spot where the channel from my marina leading to Biscayne Bay ends, the dominating number is .9.

The depth in the area right to the east of the last markers is shown
as 39.

Both NOAA charts and my Raymarine C80 show this spot to be 4 feet deep. My sounder agrees with 4 feet, which limits a little bit my freedom of going in and out of the marina, but it is definitely not 3 feet, I would have known. Perhaps the Navionics people wanted to emphasize that it is indeed no more than 4 feet there? Not 4.4, for example, which would be consistent with simply "4"? Obviously, it is impossible to accurately measure depth everywhere along the cost at 0.1 ft precision, so there mast be some other explanation why they are doing it this way.

As for the pink birds, I looked at them a little more, and it appears that they are lpaced within the US territorial waters.

[dacust]

I had noticed those before and thought I only saw 3,6,9 on charts measured in feet. So I thought it was inches. And 3,6,9 would be the quarter foot increments.

-dan

[pete33458]

Well at least other people are seeing this and somewhat confused by it as well!!!! I sent LostHorizons' useful attachment to Raymarine; will keep you posted.

[Lost Horizons]

One more observation: I switched feet to meeters inthe settings, and that "3.9" soundings figure changed to "1.2." Now, 1.2m is almost equal to 3.9 feet. So I think the data on this version is stored in some units that after conversion to a desired system is dispalyed with decimals without being rounded.

[pete33458]

Here are the answers from Raymarine:

Regarding the little pink birdies:

"The symbols and grid are contained in a cartography layer that cannot be turned off. The grids are marine resources leasing boundaries and the bird symbols denote sanctuary areas."

Regarding the small numbers to the lower right of chart soundings:

"It appears that these subscripts are used in conjunction with units for spot soundings. If you move around the bay, you will find that subscripts other than 9 will be displayed. In the case where depth units are configured to feet, the subscript will report fractional feet. For example a spot sounding shown on the screen as 11 subscript 8 will change to 3 subscript 6 after the display has been configured to meters (i.e. 11.8' is approximately 3.6 meters)."

This latter one leaves me a little unsatisfied; as I said above, it seems to me that if these were truly fractional units, there would be a random distribution of all numbers from 0-9; but this isn't the case on my chartplotter, nor is it the case on Lost Horizons' attached image (where every "fractional" number is a 9...).

Well, at least part of the mystery is laid to rest! pete