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Author Topic:   GPS/ChartPlotter Info
Jerry Townsend posted 04-30-2002 11:15 PM ET (US)   Profile for Jerry Townsend   Send Email to Jerry Townsend  
I am looking at GPS/ChartPlotters and am uncertain as to the benefits of the C-Map NT (Offshore & Inland) and the Garmin Topo MapSource and BlueChart data. I therefore appreciate any information (resolution, detail, accuracy, and comments of those having used these map sources. Thanks ------ Jerry/Idaho
triblet posted 05-01-2002 12:01 AM ET (US)     Profile for triblet  Send Email to triblet     
The benefit is that you can see where you are
on the chart. Much easier to use than a non
charting GPS. A secondary benefit is that
you learn a lot of place names:

Bayliner owner: Mayday, I'm sinking off the point.
CG: Which point?
BO: The one in Pacific Grove.
CG: Which of the four points in PG?

No kidding, I've heard roughly this
conversation a couple of times.

You can see the Garmin topo charts on their
website. Topos are good for lakes, and
passable for ocean. BlueCharts are for the
ocean, Great Lakes, and maybe a few big
rivers. Blue Charts paint the screen rather

See also:


Jerry Townsend posted 05-01-2002 01:38 AM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
Chuck - thanks for the info - you are quite experienced and knowledgable with the Garmin chartplotters. Can you compare the Garmin Topo & BlueCharts versus the C-Map NT map systems. ---- Jerry/Idaho
John from Madison CT posted 05-01-2002 06:46 AM ET (US)     Profile for John from Madison CT  Send Email to John from Madison CT     

I have the Bluechart chip in my Garmin 182. All I can say is WOW. Amazing detail.

I did my homework while shopping for a GPS and found the Bluecharts to have considerably more details than the C-Map chips or software.

Good Luck,


kingfish posted 05-01-2002 09:02 AM ET (US)     Profile for kingfish  Send Email to kingfish     

I currently have two Garmin 235's (combo chartplotter/sounder) that utilize G- (not C-) Charts, and one Garmin 76Map handheld chartplotter that utilizes Blue Charts. Can't speak to C-Charts. There seems to be more detail in the Blue Charts (than G-Chart), but the biggest thing I think is that the system in which the Blue Charts are utilized is much more flexible and comprehensive. You can buy other CD's (hot fishin spots, lights and buoys (or something like that) and the like. The good news is that you can run these CD's on your PC or laptop then download the parts you want either directly into the GPS or onto a data card that goes into the GPS. The bad news is that you have to run these CD's on a PC or laptop so you can download data directly to your GPS or data card. This system has replaced (by evolution) the G-Charts that I have in the 235's.

All the data is expensive, whether you buy ready-made cards with the data on them or download it yourself. Unless the C-Charts are a medium that will accept downloads from the Blue Charts (and therefore are just a part of the larger system), my personal recommendation would be the Blue Charts.


aubv posted 05-01-2002 11:10 AM ET (US)     Profile for aubv  Send Email to aubv     

I just purchased a Garmin GPS/Chart plotter 2006c with a large Blue chart chip and I am astounded by what this equipment can do for you. I think GPS chart plotters are worth having and think the larger the better. First time I used ours it was in an area that I had never been with tricky channels, on a day with three-four miles visibility. All I had to do, if I couldn't see the next buoy, was look at the gps and then look in direct indicated and there would be the buoy. Probably save me a prop already.

Everything I have read, Blue Charts seem to be the overwhelming choice because of detail.


where2 posted 05-01-2002 05:22 PM ET (US)     Profile for where2  Send Email to where2     
The Standard/Horizon CP150 is C-Map_NT+ compatible and retails for around $400. C-Map charts have all the detail that a NOAA chart has, because they're from the NOAA charts. Find a shop that sells high-end marine electronics and you will find that C-Maps are the standard, not Bluecharts. If you're fishing inland lakes, maybe all you want is a Garmin and Topo maps or Bluecharts. Don't bother with the Garmin Waterways and Lights CD, I have found the shoreline detail worthless, and the marker positioning poor (to put it kindly). Garmin TOPO was nice for the car, but I wouldn't rely on it for boating. Bluecharts looked better (showing depths), but If I were spending the $$$, I'd get a C-MapNT+ unit.

The next real world comparison is screen refresh rates. The CP150 can redraw the screen as fast if not faster than most of the Garmin's I've ever seen. Firmware updates for the CP150 come in the form of a C-Map cartridge which you insert which rewrites your unit, on your boat without any new cables, or monkeying around. In less than a minute, you remove the special update cartridge, and insert your standard chart again. To update a Garmin, you need the computer interface, and the software you downloaded from Garmin's website. Then you need to reload all your charts again from your CD, if I'm not mistaken.

SSCH posted 05-01-2002 07:56 PM ET (US)     Profile for SSCH  Send Email to SSCH     
I own a Garmin 176c that uses Blue Chart data on a data card. I also own Visual Nav 4.0 and a set of Map Tech cds for the same region (upper Texas coast). The redraw rate for the 176c with its vector charts appears as fast, or faster than, my PIII 900 mhz laptop with the raster charts using Visual Nav. I think the detail in the water with Blue Chart is okay, but the raster charts are better. The Blue Charts are easier to read (clearer numbers for example).

If you go with the Blue Charts be sure to get the USB card programmer to speed up the process of loading charts into your data card. 16 or so megs is probably plenty for a single Blue Chart region. I've got a 64meg card and have loaded all the roads and recreational points along the Texas and La coasts as well as all the charts from Corpus Christi to New Orleans, with lots of space to spare. You couldn't begin to store this much data in this space with raster(C charts).

More questions? I'll be glad to try to answer.


Jerry Townsend posted 05-02-2002 12:01 AM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
I thank everyone for the information, insight and experience on the GPS/ChartPlotters. Sure makes the decision a lot easier. ---- Jerry/Idaho
triblet posted 05-02-2002 12:52 AM ET (US)     Profile for triblet  Send Email to triblet     
I can't compare to C-Map NT. Too bad both
C-MAP and Garmin don't have websites where
you can compare (Garmin does, but not for

You don't have to reload the BlueCharts
after a Garmin firmware update.

At least
for me, where the boat's at the house when
it's not on the water, it's far easier to
bring the GPS to the computer to do a
firmware upload than to deal with UPSing
a cartridge around. Also, by bringing the
GPS to the computer, I can make a back up
of all the waypoints and routes into the

The entire California Region, Eureka to the
tip of Baja and a bit further, including the
Sea of Cortez, is 6.9 Meg. If you just
potter around on a bay, a couple of meg is
fine. I have the whole San Francisco area,
and a lot tops in the 2.5M on my 162. For
those sizes, you don't need the USB burner.
It takes about a beer to burn the whole lot.
BTW, if you add a map, you have to reburn
them all.

For the US, BlueCharts cover the saltwater
coasts, except for most of Alaska (only goes
up about as far as Kodiak Island) and the
Great Lakes. No little lakes, no rivers.

The Standard 1x0 series looks pretty good.
If I were buying a GPS right now, I'd be
giving them a good look. I was drooling at
the Garmin 2006c at West Marine today.
Not this year. I'd put on 2010c on a
Defiance. ;-)


kingfish posted 05-02-2002 10:05 AM ET (US)     Profile for kingfish  Send Email to kingfish     
Jerry (FWIW)-

Re: Blue Charts and Garmin Waterways and Lights CD; Blue Charts are developed from NOAA data also and as a consequence they are what should be used for navigation. The Waterways and Lights data overlays the Blue Chart data in real world use, and rather than acting (or being intended to act) as the reliant data for navigation, they offer a great deal of additional interesting and useful information when used in conjunction with Blue Chart data.


triblet posted 05-02-2002 09:02 PM ET (US)     Profile for triblet  Send Email to triblet     
What's on W&L that's not on the BlueCharts?


kingfish posted 05-03-2002 10:29 AM ET (US)     Profile for kingfish  Send Email to kingfish     

I'll open mine up when I get home tonight to refresh my memory and so as not to inadvertantly confuse content of one with content of the other, and then post back here.


kingfish posted 05-04-2002 01:07 PM ET (US)     Profile for kingfish  Send Email to kingfish     

Here's my best shot at your question above:

First of all, a large segment of the additional information I was thinking of, Marina information and tide predictions, turned out to be a part of the Blue Charts and not a part of the W & L. Senior moment.

After that, assuming a Continental United States Blue Chart on which you have not purchased any key to open up navigational detail for any areas at all, the land-based information, (cities, lakes, major roads, etc.) is largely the same on both down to 50-mile scale. Below that, (next magnification is 30-mile scale), the detail drops off the Blue Chart. That is, place names, road names and the like disappear, leaving just the lines that make up the map but with nothing titled or identified. Of course, all the information on the W&L remains accessible down to the largest scale. No lights, markers or waterways show up at all at any scale on the undetailed Blue Chart, but those things start to show up on W&L at 30-mile scale, and get fully detailed by the time you're down to 2-3 mile scale.

Now in any Blue Chart area that you have purchased detail key(s), as near as I can tell, virtually all the information that is on W&L is also on the Blue Chart, but just for the keyed area. In keyed areas, in addition to the lights, markers and waterways (and land-based data to all scale), the Blue Chart shows NOAA data with depth contours. Additionally the Blue Chart has detailed Marina locations and data, and tide prediction data in all areas, keyed or not.

I don't know if I've managed to convey what you needed to know; let me know if not and I'll try it from a different angle.


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