Features May 1, 1998 Issue

Handheld GPS Chart Plotters: Watch Out For That Rock!

The new generation of handheld GPS chart plotters accept plug-in cartridges for close-in details. Our test of three GPS’s and their respective cartography finds they all work well on the ocean, but for inland waters navigation, you’re better off with a gas station map or even a tourist T-shirt.

Almost all portable GPS receivers include track plotting that may sometimes be confused with electronic charts. The units discussed here, however, have in addition to all the normal GPS functions the ability to display your position on an electronic chart.

There are two types of cartography available with handheld GPS chart plotters: imbedded base maps pre-installed in the unit, and separate chart cartridges inserted into a slot for specific geographic areas.

Most of the imbedded base maps are only rough outlines of North America, and won’t show up on the screen when you zoom in closer than 64 miles. While the imbedded rough base map might impress your guests, you cannot zoom in on your position for closer-in detail. To obtain detail, you need to buy a GPS that accepts small chart cartridges, purchased separately. In this review, we look only at the latter group, focusing primarily on inland charts.

The First Portable GPS Chart Players
The first three portable GPS chart plotters have strangely disappeared from the current marketplace.

Remember the Sony Pyxis model 760? Sony tested the US market with this set for about two years, and then quietly shifted this equipment to national close-out catalog distributors. Boat owners were concerned about the rather large delicate swivel antenna assembly on the top of the unit, and may also have suspected that the equipment was designed more for the Japanese auto and outdoor market than for boat owners. They may also have been concerned about the unique chart cartridge that fit only the Sony.

“We stand behind all of our different styles of chart cartridges used by various manufacturers,” said Ken Cirillo, vice-president and general manager of C-Map USA, “and we stillmaintain a library of chart titles for the Sony Pyxis.”

Several years ago, Raytheon introduced the Raystar 198 portable GPS chart plotter that worked with C-Map CF85 chart cartridges. (C-Map still updates and releases new CF85 mini-cartridges.) The Raystar 198 would upload the chart cartridge data from a docking card reader, and then run with the data without the need for the actual chart cartridge. The Raytheon product was troubled with an LCD screen that lacked contrast and turned almost black in direct sunlight. It lasted about one year.

And there was the Panasonic portable GPS chart player that used Navionics cartography on a PCMCIA card that inserted into the bottom of the Panasonic set. During our sea trials, it was a battery guzzler, depleting four alkaline cells in about 3-1/2 hours. The unit was also tested for its “weatherproof” claims, and it leaked water easily into the battery compartment and the LCD face quickly fogged up.

Current Charting Systems
The three products in this test performed much better. We tested the Magellan 6000 2-channel model that uses C-Map NT cartridge cartography (a 12-channel model should be on the market soon); the Garmin GPSMAP 175 using the proprietary Garmin G-chart; and the Lowrance Global Map Sport that offers two internal Lowrance-cartridge slots. Both Lowrance and Garmin contain imbedded base map cartography, in case you don’t have the right cartridge aboard.

C-Map, Navionics, and proprietary cartridges are not interchangeable. You must use the type for which your GPS is designed. None is perfect. We'll give you our assessment based on the cartography for Lake Mead, Nevada. Of the three, C-Map is compatible with most chart plotters on the market, including Autohelm, Raytheon, and Si-Tex.

How We Tested
In addition to charts of the ocean, charts of inland waters and roads also are available, and we were curious to see how well they worked. At Lake Mead, we wanted to see how the units would perform when running down a narrow passage with 500' cliffs on each side of the boat. This would be a good test of the GPS receiver section of our portable charters. We also wanted to test how C-Map, Garmin, and Lowrance developed their inland cartography. Would lakes and rivers come with bottom contours? Could we find those small launch ramps that we see on a local paper map? What about those small towns located at the edge of a lake that might have fuel facilities, lodging, bait, and launch ramps? We figured the brand new pop-up towns wouldn’t be listed, but would some of those that had been around for years be on the inland charts?

We also wanted to test the LCD displays in bright, hot sunlight. Would they keep their contrast when outside temperatures exceeded 110°F? How well could you see these displays wearing polarized glasses? And are portable GPS charting displays simply too small for use in a fast boat or a car traveling 55 mph?

Finally, we wanted to determine battery life and each unit’s resistance to water.

Lowrance Global Map Sport
Lowrance scored several “firsts” when they introduced the Global Map Sport into the marketplace almost five years ago:

• First with two chart ports.
• First with an imbedded base map not requiring any chart cartridges.
• First with a brilliant electroluminescent, back-lighted 160-pixel x 160-pixel, 2.25" inch square screen.

Lowrance said that it has upgraded the Global Map Sport from a Rockwell 5-parallel channel receiver to the new Rockwell 12-parallel channel receiver. We got a brief look at a prototype; acquisition time on a coldstart to a first fix was less than a couple of minutes with the 12-channel (keep in mind that these were “cold” fix initial turn-ons) and an agonizing 15 minutes on the older 5-channel receiver. “Warm” start-ups were timed at about 41 seconds. With the 12-channel receiver, we saw a dramatic increase in chart refresh speed, but otherwise both units gave almost identical performance, even in areas with steep mountains on each side of our test boat. The 12-channel was not available to the consumer at the time of this writing.

The Global Map Sport runs on 6 AA batteries that fit into a spray-resistant, slide-on holder. The holder may require a strong tug to slide off, but this is good in that one can be assured of a weatherproof seal. When we ran AA alkaline batteries, we got up to 6 hours of continuous play time. We next used AA rechargeable nickel cadmium batteries, and play time decreased to 3 hours. Although the Global Map Sport can take auxiliary 12 volts, it won’t recharge nickel cadmium batteries. To recharge nicads, you need to open up the battery tray, pull out the cells and put them in a nicad battery charger. We’d have liked to have seen internal charging capabilities.

The Global Map Sport uses a flip-up patch antenna that doubles as the screen protector. This is a great idea as you can remove the antenna from the body and mount it elsewhere with a patch cable. For our tests, however, we left the antenna mounted on the body.

After turn-on and satellite acquisition, our position came up as a blinking diamond with an X in the middle, superimposed over a base map. The base map contains cartography of the entire world with detailed emphasis on the 48 contiguous states, the Hawaiian Islands, southern Canada, and the Caribbean down to and including the Virgin Islands and along the northern coast of Honduras. Most amazing is that the base map shows major roads, bridges, lakes, rivers, and other points of interest. If you trailer a boat, the base map will show your track along all major highways.

For more detailed cartography, two ports on the backside accept Lowrance cartridges. The cartridges look similar to C-Map NT cartridges, but they are not. Cartridges could be Lowrance’s own inland mapping system “Smart Maps,” or they could contain the cartographic information from C-Map charts. Again, regular C-Map NT cartridges won’t work in these cartridge holders—you must buy Lowrance charts in their proprietary cartridge holder.

We loaded our unit with two cartridges—one filled with C-Map inland cartography covering Lake Mead, Nevada, and the other cartridge from Lowrance’s own data base of mapping covering Lake Mead, Nevada.

What we found was good to excellent detail of Lake Mead, but neither cartridge gave us any kind of detail when it came to small access roads, launch ramps, fuel docks, and other points of interest that we found on paper maps. In fact, one of our cruising guests had a T-shirt of Lake Mead that had more information than the inland chart cards!

C-Map inland cartography gave us some spot depth soundings as well as some bottom contours whereas Lowrance cartography only showed water. Little islands on both cartridges looked more like blocky zigzags than what we saw in real life or on the paper charts. And many times we would cruise by paved access roads to a launch ramp that didn’t show up on the inland cartridges.

During our test, both chart cartridges came through in showing us a new way to get home. We had accidentally made a wrong turn, and on the course we needed we were confronted by a steep cliff ahead. We couldn’t believe that there was a passage through the steep cliff, yet both cartridges showed that there was. Sure enough, as we got within several hundred yards of the cliff, there was the passage. That’s something you couldn’t do with radar.

The Lowrance Global Map Sport comes with over 20 different screens of information that may be customized. You can split the map with information on the right and the map on the left. You also can program the window to show a map in one quarter or on one side, a steering compass on the other, and speed information in another corner. You can navigate with a giant compass filling the entire screen, or put the compass down in one corner, the map in another, and have two idle boxes for any other information you might want to plug in. We counted over 48 individual window settings that are fully programmable.

One nice feature after our trip on Lake Mead was the capability to download all of our waypoints to a PC for later scrutiny. An optional wiring kit is available for this purpose. There is also an optional cable kit for differential GPS reception.

But the best feature of the Lowrance Global Map Sport was the ability to switch between two different internal chart cartridges without having to unplug one and plug in the other. This way you can cruise back to the launch ramp on detailed C-Map cartography, and then switch to the inland highway maps to accompany you on the drive home. Pretty neat.

The overall operation of the Lowrance Global Map Sport was straightforward and easy to use without having to read the manual from cover to cover. The large display stayed extremely sharp even in direct sunlight.

The Lowrance got a bit wet during our test, but there appeared to be no problems with fogging of the display or with moisture entering the battery compartment. When we stripped it down, it was bone dry.

Lowrance customer service seems to be very good. We called the factory to ask some questions and got through on the first ring. The product specialist took the time—20 minutes—to answer every question we had about operation of the unit.

The company president, Darrell Lowrance, is a private aircraft owner, and a different version of the Global Map Sport is offered for pilots.

Bottom Line: The Lowrance Global Map Sport is a good unit that is showing its age. We'll review the new 12-channel version when a production model is available.

Garmin GPSMAP 175
The Garmin GPSMAP 175 is a 12-parallel channel portable GPS charter that gave us a “cold” start position fix within 35 seconds from turn-on. “Warm” start-ups took about 22 seconds. The factory tells us it pre-positions the GPS in Olathe, Kansas, and the 12-channel receiver is agile enough to find the satellites on either coast in a matter of seconds, just as long as it knows the current date.

The Garmin GPSMap 175 is almost the same size as the Lowrance unit, but over an inch thicker. This is because the batteries are in the back side of the unit, rather than on the tail. The Garmin uses 6 AA batteries, and we were able to run it up to 9 hours and 45 minutes continuously, longer than the other two models tested. You press a tab to unlock the battery tray on the back of the unit. The battery tray then slides down, and pulls off for easy cell replacement. There is an optional rechargeable Ni-cad battery pack and charger that is available, in addition to a 12-volt DC power connection that might allow you to hard wire the unit for long running periods without internal battery consumption.

The GPSMAP 175 was recently updated with the same base map that is now found in the smaller Garmin GPS III. This is a plus because Garmin’s base map is a lot more up to date than the Lowrance base map. Without any cartridge installed, the Garmin GPS Map 175 will display millions of miles of highways, interstates, railroads, rivers, and shorelines. But don’t get overly excited, because the base map is more for navigating in your car than aboard a boat.

At turn-on, you will see a picture of the United States. If you compare this LCD display to the Lowrance you will see four levels of grayscale, whereas the Lowrance has just three levels. You will also see a higher pixel count of 160 x 240 pixels on the 3.5" x 2.3" LCD display. Of the three units we tested, we liked Garmin’s display best.

To speed up initialization, we used the keypad to move the map cursor to our Lake Mead location, then pressed “Enter” to confirm the selection. Immediately we saw hollow signal strength bars which indicate the unit has locked onto satellites, and the bars went solid indicating the receiver had collected the necessary almanac and was ready to display its position.

Until we selected the proprietary Garmin G-chart, we navigated around the waters with the base map. While this base map certainly has more up-to-date information than the Lowrance, its display of shorelines was dramatically inferior.

We ordered the Garmin inland G-chart cartography for Lake Mead. Garmin develops its own inland cartography from US Geological Survey maps, plus other local sources. It’s then custom-loaded into a proprietary G-chart plastic cartridge which fits into the side of the unit. If you decide to use this set out on the oceans, the same style G-chart will contain Navionics cartography.

Cartridges can be installed with the unit on or off. Other equipment advises to always install the cartridge with the equipment off. When we plugged in the cartridge, the Garmin sounded a beep and we then closed the rubber door and watched Lake Mead begin to unfold before our eyes.

We could immediately see a big improvement on the shoreline details of Lake Mead. But there were no bottom contours or the small rocks that we could see sticking out of the water a couple hundred yards from shore. These rocks were noted on our paper map but not on the G-chart.

While we did see a few more launch ramps than C-Map offered on the Lowrance cartridge, we didn’t see some of the small paved roads. Many marinas also didn’t show up.

Operating the Garmin was a pleasure, and the high-visibility LCD screen held up fine to the baking sun. We ran the unit with one hand; the placement of the keyboard on top above the screen made this easier.

At the front of the keypad is the patch antenna that worked well.

As we were cruising down the lake, we noticed the chart refresh time was slightly slower than the Lowrance. We also noticed that zoom-in and zoom-out took a little bit longer than the Lowrance and Magellan sets. But once we got to the scale we wanted, the visibility of the display was far superior to Lowrance or Magellan.

We think that Garmin, with its own in-house land cartography division, will continue to make improvements to inland cartography. Garmin previewed for us a new land product for cars and recreational vehicles that should give even greater detail to those small lakes, launch ramps, and hideaway spots on Lake Mead.

Bottom Line: Superior display, longer battery life, and 12-channel receiving that produces a much faster acquitision time, at an attractive price, make the Garmin our top choice.

Magellan NAV 6000 GPS
Magellan was a little bit behind Lowrance and Garmin with their NAV 6000 because of production problems with the high-contrast, four-level LCD screen. They wanted a unit that wouldn’t have any problems with an oversized screen, and they succeeded. Their large 3" high by 2-1/2" wide screen held up well to the hot Lake Mead sun.

The Magellan takes 6 AA batteries that are inserted from the bottom of the unit. You turn two thumb latches to gain access to the battery compartment. The battery compartment has the port for C-Map NT cartridges. Battery life was measured at 8 hours.

“Cold” start acquisition time was about 3 minutes. “Warm” start acquisition time was 1 minute 30 seconds—both slowest of the group.

Without a C-Map cartridge inserted, the Magellan gives you a base map of the US. But you can only zoom down to 150 miles before going into the track-only mode. In other words, the base map merely shows the outline of the United States, and almost nothing else. Not even state boundaries, lakes, rivers, or ports.

But once we inserted a C-Map NT cartridge, the screen sprang to life with all the detail needed, zooming in or out for viewing coastlines, depth contours, restrictions, nearest ports, navigation aids, and other charting information.

As we mentioned, the Magellan NAV 6000 uses the same C-Map NT cartridges as 25 other marine electronic GPS charting systems, including those from Autohelm, Cetrek, Datamarine, Echo Tech, JRC, Standard, Magellan, Raytheon, Simrad, Si-Tex, VDO, and Vision.

Because C-Map NT ocean cartography is so common, we had several spare ocean cartridges that worked well in the Magellan NAV 6000. But the ocean cartridges don’t cover anything inland, so we turned to the new C-Map NT charting systems of inland cartography. C-Map has been expanding into the inland market using the same horizontally seamless format as the ocean NT cartography. When we picked out an inland cartridge covering Lake Mead, we saw that it consisted of US Geological Survey 1:100,000 scale maps. The continental US is divided into about 75 C-cards at $99 each. This database is only available in the NT format, and is based on the 1:100,000 USGS database. Cirillo said C-Map also has a new world background map, with state boundaries, maps, geographic names, major rivers and more. “It will do our inland C-cards justice,” he said.

We purchased several C-cards that overlapped to ocean regions because we wanted to see if we could get both ocean cartography as well as inland cartography on one cartridge. Sorry, the answer is no. In fact, attempting to cruise along a coastline with inland cartography can get you into some serious trouble. While there might be outlines of the Port of Los Angeles, and while the inland cartography might show major roads near the port, inland cartography will not show you manmade objects like breakwaters, super-tanker terminals, and the like. It’s the same for cruising around islands—you might see your favorite island with all sorts of roadways on it, but the inland cartography won’t show you some of the dangerous lighted rocks a half mile off the coast.

When we operated the NAV 6000 on Lake Mead, we could clearly see the advantage of a 12-parallel channel receiver vs. the Magellan’s 2-channel receiver. While position accuracy was the same on all three units, the Magellan would regularly lose a satellite fix when we approached cliffs. It was also more sluggish when we accelerated. Both the Garmin and the Lowrance did a much better job of quickly tracking small speed changes.

When it came to map details on Lake Mead, the C-Map inland cartridges were no better than the Lowrance inland mapping system cartridges, and no better than the Garmin inland G-charts. Things like small launch ramps, marinas, small towns, and RV parks were seen on a paper map, seen live in person, but not on the electronic screen.

We did, however, like the presentation of the C-Map inland cartography when it came to bottom contours—there was a lot more detail of the lakefront on the C-Map cartridge than the other two. Remember, Lowrance uses C-Map data for their ocean cartridges, but their own data for their inland cartridges.

We found the Magellan NAV 6000 easy to operate without pouring over the instruction book. Once you figure out that four buttons near the bottom of the screen relate to information on the screen, you are all set. And while we judged the Magellan NAV 6000 screen as good, we didn’t find it had the contrast of the Garmin screen.

Magellan tells us that a new generation of NAV 6000 will incorporate a new 12-parallel channel receiver. This is good news for cruising on lakes with steep mountains that might block satellites. But out in the open, the Magellan 6000 did a great job of locking onto all satellites in view and giving us an agile position fix as we watched ourselves drive down the C-Map highways.

Bottom Line: The 2-channel receiver regularly lost satellites when near cliffs, and was sluggish in tracking speed changes. It’s easy to operate and we like the large display. But, as with the Lowrance Global Map, we’d wait for the new 12-channel model due out soon. We had a look at a prototype and its acquisition and refresh times seemed much faster.

The best performer of the three was Garmin, not surprisingly since it also has the newest technology. It also had the shortest acquistion time, longest battery life, and best display. It also had the best land base map, which also did a fair job of showing Lake Mead.

The unit with the best coastal base map was the Lowrance Global Map.IT also has one particular feature we’d like to see in other units, and that is two cartridge slots.

However, if you already have C-Map cartography, stick with the Magellan NAV 6000. It's new 12-channel unit should be on the market this spring.

And remember that both the Magellan and Lowrance (at least for offshore purposes), instead of using dedicated charts, make use of the much more versatile C-Map NT cartridge.

Be all this as it may, none of the three units have inland cartography that really gets down to small roads, launch ramps, bait shops, small marinas, pumpout stations, and tiny coves. If the cove is along a coastline, we'd recommend going with regular ocean cartography. For inland navigation, all three manufacturers still have a long way to go before they can say that their inland cartography is truly as detailed and useful as local paper maps. There's definitely room for improvement here and, in time, it no doubt will occur.

Contacts- C-Map USA, 133 Falmouth Rd., Mashpee, MA 02649; 508/477-8010. Garmin, 1200 E. 151st St., Olathe, KS 66062; 913/397-8200; Lowrance Electronics, 12000 E. Skelly Dr., Tulsa, OK 74128-2486; 800/324-1356; Magellan Systems, 960 Overland Ct., San Dimas, CA 91773; 909/394-5000.

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