Paper Chart detail vs. Electronic Chart detail

[Hermit Scott]

I have never used a chart on my chart plotter. I could only see where I was with respect to land, there was no depth information. I finally got around to buying an electronic chart for my plotter. The zoom goes to 1/2 NM. Other charts go to 1/8 NM. While others best zoom is 1 NM.
(1)What level of detail or zoom is there on paper charts that you guys use to navigate bays and ICW, coastal ocean?
(2)What level of detail or zoom is there on chart plotter charts that you guys use to navigate bays and ICW, coastal ocean?

 

[RichH]

Much of US waters charting is based on upgrades of datums, etc. taken in/around/before 1929 and is still being 'updated'. The REAL problem with vector (ENC) charting is that the 'resolution of error' is too great when using e-chart magnification at much less than about 1:15,000. Using an e-chart in unfamiliar waters at less than 1:15000 is a sure recipe for going up on the rocks ... because of the 'error resolution' issues.

 

[alexco38]

I use vector chart on chart plotter for distance navigation (mostly cruising and racing) but switch to raster (SeaClearII) or paper chart for near shore and near shoal purpose.

You can't depend on vector chart as they are much less detail than raster chart.

 

[Paul Mermelstein]

While there is no one right answer for all people, I and most of my sailing friends in the Chesapeake use both a good chart plotter and the paper charts.

The paper charts are not just for backup, but is used to see the big picture, provide a different perspective, and provide additional information. The chart plotters we use range in brand, age, and model but most of us have good depth contour and other data as well as good support for plotting routes, laying in waypoints, integrating with radar, etc. My system (Raymarine RL70CRC) is over 6 years old, but still quite functional. Of course, I update my electronic chart chips every couple of years.

That said, my plotter routinely goes down to 1/8 or 1/4 nm if the data is there and 1/2 nm otherwise. By "there" I mean that some areas, like Annapolis, Baltimore, etc. are provided on the chip at great detail while other more isolated areas only go down to 1/2 nm. Depends on the data on the chip, not the chartplotter.

Hope this helps.

 

[Guest]

Chart datum

I've been using a Garmin 178C Sounder since 2005 and have all the Garmin charts for the regions I sail in (500+). The level of chart detail is determined by locale. For example the narrow channel we frequently navigate will let you drill down to about 150 feet elevation, which provides the necessary detail for safe navigation. In more open waters such as a strait the chart data provides sufficient detail down to 500 feet elevation.

I seldom use paper charts, but have them in the unlikely event the Garmin fails. All the chart data I need is provided on the Garmin system and I have found it to be very accurate. Having 500+ charts on a data card the size of your thumb nail as opposed to paper makes lots more sense to me.

Terry Cox

 

[Hermit Scott]

When you say the chart "goes down to 1/2 NM" does that mean that the full screen of the plotter represents 1/2 NM?

 

[Stu Jackson]

Usually the chartplotters, or even my Garmin GPSMap 76Cx, shows a SCALE at the bottom of the screen that will indicate the "coverage." Mine goes down to 120 feet, yes feet, before it says "Overzoom!!!", but that's when the scale says 120 feet, and the visual chart is usually about four or five times the scale dimension, so what you see on the screen is 120 feet times four or five.

 

[Ed Schenck]

This level of detail discussion is interesting. On our trip from Lake Erie to north of Tampa we never used the paper charts. The Garmin 172C always had us in the middle of the channels and between the markers. What it did not do is tell us where the ICW had shoaled over. We found narrow marina inlets in the dark and our way back in from offshore. We found the indicated depths to be accurate with the ICW exception. Not sure what else we needed.

 

[tommays]

My 99 dollar Lowrance natipath chip has never missed anything that was on a paper chart other than notices to mariners that you need to mark on a paper chart anyway

And a LOT of paper charts are REALLY out of date due to money issues JUST look at the dates on parts of brand NEW charts

 

[RichH]

This level of detail discussion is interesting. On our trip from Lake Erie to north of Tampa we never used the paper charts. The Garmin 172C always had us in the middle of the channels and between the markers. What it did not do is tell us where the ICW had shoaled over. We found narrow marina inlets in the dark and our way back in from offshore. We found the indicated depths to be accurate with the ICW exception. Not sure what else we needed.

I just returned in early July from the Caribbean back to the Chesapeake. Forced by weather to travel mostly 'up the ditch' (ICW) and/or 'hugging the coast', I was amazed that the latest eCharting was clearly WRONG about ~1/2% to 1% of the time (especially a HIGH magnification) ... and errors were very glaring errors --- the ICW in several places was 1/8-1/4' mile 'off' of the charts, MAJOR (& long standing nav. aids) were 'way out of sync' with these 'latest e-charts' (based on the supposed latest NOAA, etc. charting/surveys). I use both the NOAA ENC (on laptop coupled to GPS AND standalone Garmin chartplotter... and both validated the same errors. Interesting that the old paper charts and the physical 'marks / nav. aids' for these 'anomaly' areas were still correct.

 

[Benny]

It seems the older chartplotters Garmins 162,172,182 required maps to be purchased and the map scale automatically adjusted to the waters being navigated and the destination but also allowed zoom in and zoom out along a route. We borrowed a boat to take from the Chesapeake Bay to NYC and it was equiped with a Garmin 440. It was a nice color display unit which supposedly was loaded with full US coastal maps. Well for long route planning it was practically useless as it only showed details at .2nm and .8 nm. The darn thing had us running for paper charts in Cape May and we came to the realization that very few entities carry paper charts anymore. I'm aware that you can purchase a chip with detailed area maps at approx $325 per region but would have thought the included basemaps would have been a little more helpful. The unit had information on projected currents which was helpful but it was harder to operate than the olther units and the basemap inclusion feature is practically useless.

 

[Hermit Scott]

The base map on mine had no depths. In the pictures where it describes the 'unimap' there are depths and contours, but in reality it is showing the navionics gold maps. This weekend I will get to play with my new chart and try to get proficient enough to use the plotter on my first trip out into the ocean on labor day.

 

[sinnettc]

The base maps on my Eagle SeaCharter 642c DGPS don't do much for me either. I bought the Navtech chip for the PNW and it gave me pretty much everything on the paper charts with what appears to be pretty good detail.

That said, I've purchased a Maptech waterproof chart pak (spiral bound) of the San Juans, downloaded two different pc charting programs (the old free Maptech one and OpenCPN) and all of the (free!) vector and raster charts for OR/WA from the NOAA site. NOAA also has an experimental PDF file offering of the paper charts broken down into an 8x11 booklet that you can print and bind yourself.

When we go up there next year I'll have the SeaCharter installed, my old Magellan GPS 315, a laptop with the most recent chart updates, the chart pak, and possibly one of the DIY 8x11 booklets if I can get my printer to cooperate.

Chris

 

[sailaway78]

Garmin

My experience on the ICW on the east coast is different than RichH. I found the Garmin 498C to be dead on, on a trip from Sandy Hook NJ back to New Orleans. Zoomed in, it shows depth and very good detail. The Garmin will tell you how accurate it is, depending on the sat. fix. Usually says accurate to within a few feet. On my previous boat, with a Garmin 182, I did find a place down in your neck of the woods that was off, approx 1/8 of a mile. Somewhere along the ICW, and for several miles it was showing me up on dry land. I think is something to do with the way the chart is in registered as it is scanned. In the instance when I was showing to be out of the channel, you could see the difference when it scrolled to another chart, and I was right back in the water again.

 

[Hermit Scott]

The map that came with my unit showed me out of the ICW also. I thought I might need to calibrate it somehow. Maybe it was just the map. Hopefully it will be corrected with the new charts.

 

[Ross]

These charts are as up to date as can be had. I would not go anywhere without them in hand in some form.
http://ocsdata.ncd.noaa.gov/BookletChart/

 

[NC-C320]

OCS Charts

These charts are as up to date as can be had. I would not go anywhere without them in hand in some form.
http://ocsdata.ncd.noaa.gov/BookletChart/

Ross,

Thanks for posting this link. These charts can be printed down in a series of 8x11 segments suitable for a cockpit guide and are great, especially for single handers. A chart table and full size chart down below at a navigation desk is not always convenient for single handers, a 8 x 11 chart in water proof cover or note book (to hold multiple segments and other key reference data) can be a handy reference at the wheel or tiller. Anyone who hasn't checked out the OCS website should do so.

 

[Ross]

Re: OCS Charts

The site also provides instruction for double sided printing with wide margins on the left edge of the page for stapling into a booklet.

 

[rpwillia]

The origin of Maps

OK, Here is my understanding. All of the electronic charts are based off of the NOAA charts that are now available electronically on NOAA's web site. For the mainstream there are two entities that provide 90% of the charts - Garmin and Navionics. They take the NOAA charts and add "stuff" to them. Sea Clear and ONC? are two great free one but they require a PC to run on. I believe most chartplotters are running a version of WindowsCE for that dedicated hardware (display and various control buttons) with some customization by the vendor (Raymarine, Humminbird, Lowrance, Eagle, etc) to adapt to their specific hardware.

Both the Garmin and Navionics charts are encrypted and their software will only work with their encrypted charts. Not sure when, if ever, someone will port SeaClear or ONC? to those platforms so we could use the nice dedicated and waterproof hardware with the freely available NOAA maps. Nice to think about, as I like my chartplotter right there in the cockpit for reference.

 

[Hermit Scott]

I can't wait until someone makes a chart plotter that runs NOAA maps. Someone should build a cockpit computer that has a 12' screen IPX-9, with some programmable waterproof buttons, that you can run computer apps on. Then you could link everything on the boat to it. I am sure the big ships work that way.
Looking up upgrades to do on my C30(before I realized I had 2 years of repairs before I upgraded anything) I saw a guy that built a little board and LCD dispaly to show all his engine data, holding tanks, and some other things. It was pretty sharp.
If you can't do it yourself it is expensive though. I just had a board built that is nothing more than a digital bathroom scale simplified. I found an unemployed electrical engineer to do it for $1500. Companies wanted 5-10k to do it.