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Gear Review



Page Type: Gear Review

Object Title: GPS III+

Manufacturer: Garmin

Your Opinion: 
 - 2 Votes


Page By: Alan Ellis

Created/Edited: Dec 21, 2002 / Dec 21, 2002

Object ID: 9280

Hits: 74 



GARMIN's GPS III Plus offers cartographic capabilities formerly found only in high-end automotive navigation and marine chartplotting units. Simply plug it into a PC and download an extra 1.44 MB of map data from GARMIN's line of MapSource™ CD ROM's to give you instant detailed maps.

Whether you're cruising the streets or pounding the waves, GARMIN has the maps you need. Choose the U.S. Roads and Recreation CD for city street level detail and even inland marine features such as lake and river shorelines, boat ramp and marina locations. Other CD's give you worldwide coverage of coastlines, including a database of coastal cities, navaids and inland roads.

Even without additional cartography, the basemap in the GPS III Plus will get you where you're going. More than 10,000 new towns have been added to the permanent basemap, as well as airport locations, secondary roads in metro areas and even detailed exit information for the federal interstate highway system, including information about available lodging, food and service stations.



Basemap: Built-in detailed Americas Highway or Atlantic Highway basemap to 20 miles with lakes, rivers, interstates, national/state highways, secondary roads in metro areas, cities, railroads, airports and a detailed exit database for the Federal Highway system in the US only MapSource: Compatible with most GARMIN MapSource™ products. Accepts up to 1.44 megabytes of downloaded map detail.

Map Scale: Screen-width scale (500 feet to 3,000 miles)



Total: 500 each with name, symbol, comment, and map display option

Nearest: 9 (automatic) continuously updated

Routes: 20 reversible routes with up to 30 waypoints each, plus MOB and TracBack™ modes

Track Log: 1900 points

Map Datums: 106

Coordinates: Lat/Lon, UTM/UPS, MGRS, Loran TDs, plus other grids, including Maidenhead and User Grid


Receiver: Differential-ready 12 parallel channel receiver continuously tracks and uses up to twelve satellites to compute and update a position

Acquisition Times: Warm: approx. 15 seconds; Cold: approx. 45 seconds; Autolocate™: approx. 5 minutes; EZinit™: easy initialization, 45 seconds

Update Rate: 1 second, continuous



15 meters (49 feet) RMS*

1-5 meters (3-15 feet) RMS with GARMIN GBR 21 DGPS receiver (optional)

Velocity: 0.1 knot RMS steady state

Dynamics: 6g's

Interfaces: NMEA 0183 and RTCM 104 DGPS corrections

Antenna: Detachable with standard BNC connector


Size: 2.32 H x 5 L x 1.62 W inches (5.9 x 12.7 x 4.1 cm)

Weight: 9 ounces (255g) w/ batteries

Display: 2.2 W x 1.5 H inches (5.6 x 3.8 cm) high-contrast electroluminescent backlit FTN display; switchable orientation (100 x 160 pixels with gray scale)

Memory: Internal lithium battery lasts up to 10 years


Source: 10-32 VDC (4 AA batteries)

Usage: 0.75 watts

Battery Life: Up to 36 hours


Viewing: 1-2 of 2

Alan EllisUntitled Review

Voted 4/5

This is one of the first Garmin units with the downloadable Mapsource software. I've used the unit and the Topo software on many, many trips. The maps on the unit are a handy reference but not much use by themselves. At home using the PC, I plot waypoints(WPs) on the software map and mark the same WPs on the 1/24 quad. Then I download the map and WPs to the unit. In the field, I have a quick reference using the 1/24 map and the unit together. You can download a huge area, probably larger than you can hike in a week.

Shortly after I bought mine, they came out with the eTrex series. The eTrex Legend appears to have exactly the same capabilities and features, but is smaller, lighter, and a $100 cheaper. I would recommend an eTrex for use in the outdoors. The GPS III+ has a removable antenna which swivels and is somewhat fragile. The antenna is removable to add an extended roof-mounted auto antenna. The eTrex series have a built-in antenna which would be better for the outdoors.

The other down to the unit is the PC interface cable. The cable is made for a serial port either on desktops or older laptops. New laptops only have USB ports. Belkin makes a serial port-to-USB port adaptor but it only works about 50% of the time. Garmin is currently working on a USB PC interface cable, but in the mean time, it is very frustrating trying to download maps. If you have a desktop it's no problem. But I like taking a laptop in the car to download maps if the trip plan changes.

Overall, I am very happy with the unit and have had a lot of fun with it. I dropped mine down a 30 ft face and it still works fine, even after the antenna broke in half. Some airplane glue provided a quick fix. However, I would have bought the eTrex Legend if it had been out when I was in the market for an outdoor GPS unit. But if you are looking for a unit both for the outdoors and also for use in your car, this is the unit to get.

UPDATE: This unit is no longer available by Garmin.
Posted Dec 21, 2002 8:31 pm

Johan HeersinkUntitled Review

Voted 5/5

Best there is for high altitude mountaineering. Can leave the thing outside in the night, and it works next morning!
Posted Nov 7, 2003 10:56 am

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