 |
        |
           |
|
|
|
Low Cost GPS Receiver and Moving Map PC Software Reviewsby Joe Mehaffey and Jack YeazelRevised: 20 June, 2000 (Corrected for SA elimination and other details) Quoted prices are US$ GARMIN HAND-HELD RECEIVERS All current models have a 12-channel parallel receiver and acquire lock and track much quicker than the G-45(XL) and G-II. They are more reliable at tracking in mountains and heavy tree cover. Also the 90 knot restriction of the G 45 (XL) has been eliminated. Garmin specifies an accuracy of 15m rms without SA. The G-12XL ($250 v. 3.02/3.52) was introduced in January 1997 to replace the single channel G-45(XL) v. 3.50, the GPS-12 "Little Brother" ($175 v. 4.0) in June 1997, the GPS-II+ ($250 v. 3.00) in April 1997, the G-III ($360 v. 2.05) in Oct. 1997. The first mapping GPS (map CDs run from $75 to $150) was the G-III+($350 v. 2.04) released in Jan. 1999. Next came the G-12Map ($330 v. 2.04) in Oct. 1999, and the latest is the eMap ($250 v. 2.50) released in Nov. 1999. These mapping GPSs include a base map of all the Interstate, most of the state routes, railroads, rivers, and shorelines in the Western Hemisphere with seven levels of detail. An International version contains road maps of most countries in the rest of the world, and the Atlantic versions have higher-detailed maps of Europe. Basic features of the hand-held Garmin units are: At least 500 waypoints storage, 20 routes of 30 routepoints, and 1000 trackpoints (1900 with the G-III)... All have a Track Back feature that converts a track to 30 routepoints providing steering directions to navigate the Track Back route -either way. All current units have icon symbols for waypoints. Erasure of Track Back waypoints is now easier with "delete by symbol". All have a serial data or external power capability. A "three-way" cable provides for both. The receiver performance in the Garmin GPS receivers is good enough, so that in many cases an external antenna will not be necessary. Reports indicate that you may need an external active antenna to maintain continuous coverage under difficult terrain and tree cover conditions. Garmin makes three active antennas, the GA-26(C) and GA-28(29) for the G-II/G-III(+) series receivers BNC connector and the GA-27(C) for the G-12XL MCX connector. "C" designates a low-voltage version. The GA-28 (or low-voltage GA-29) pole mounted 'marine' antenna comes with a 30' cable. An MCX to BNC adapter cable is available if necessary. Garmin receivers are also compatible with most 3rd party amplified GPS antennas as well as Garmin brand. Tri-M is the only other antenna vendor making an amplified external antenna compatible with eMap, eTrex and G-12Map. Some general differences are: The G-12 and G-12XL have internal antennas. The G-II+ and G-III(+) have rotatable external antennas with a BNC connector. The G-12XL, G II(+), and G-III(+) have powered jacks for remote antennas, but the G-12 has no external antenna capability. The G-12XL is the only model with an audible alarm. Only the G-II+ and G-III(+) have rotatable screens (Horiz. or Vert). The G-12XL (v. 3.02) and G-III, G-III(+), G-II+, G-12, and G-12XL (v. 4.00) units run about 20 hours on (4) AA alkaline cells.All Garmins will accept external 12vdc power and serial data through a four pin plug, except the G-12(Map), G-38, G-40, and eMap which require a voltage regulator. See Also: Garmin G-II+ Review & Garmin G-12XL Review Garmin G-III(+) is a new dimension in GPS receivers. The G-III(+) is a significant design change and incorporates a 386 processor. Screen resolution is increased from 60x100 to 100x160 pixels with four shades of gray. In addition to zoom keys, the map can be jumped to any waypoint or routepoint and panned from that location. An interesting feature is to view the selected route in "3-D". You see a winding "road" with or without routepoint "signs". The track function has been greatly expanded. The active track can contain 2000 trackpoints which can be compressed into tracks of 250 "best" trackpoints. Up to ten compressed tracks are possible, and all (or selected) tracks can be shown on the map page at the same time. Track resolution is now ADJUSTABLE. Most pages have user selectable fields of data with 25 items available for each field. Waypoints can be assigned any of 47 Symbols, and several types of user timers are available. The route function has been re-designed, so that they are listed in alphabetical order. Routes are best created by clicking on waypoints. The old "automatic route creation" by Marking isn't available. And so far, setting in a position in the Simulator mode (as in other Garmins) to check out map software isn't possible except via a work-around described on our website. The unit has lighted keys with three levels of backlight. Font size of displayed labels are user selectable and for important navigation information are quite large. The G-III map is reported to be loaded in 4 MB of ROM. This version provides display of individual saved tracks. See: Garmin G-III Mapping GPS receiver -Product Review Garmin G-III+ ($355 v. 2.05) represents an additional step by Garmin to provide STREET-LEVEL detail USER UPLOADABLE maps to the G-III frame and features. User map memory is now built-in 1.4MB of flash RAM, programmable from MapSource CD ROMs. If the total map size is within 1.4MB, they can be uploaded at 115,000 baud (max speed). The G-III+ has new features that permit you to locate the nearest cities and expressway exits. This feature only recognizes Interstate Highway exits with the "nearest exit feature". Airports and some service facilities are also marked on the new base maps. The base map is said to be more detailed than that of the G-III. Garmin issued a WorldMap CD in Feb. 1999. Garmin eMap ($250 v. 2.50) is a NEW KIND of GPS receiver system. It's basically a "shirt pocket size" GPS with simplified controls and features, far fewer than in "ordinary" GPS receivers designed for hiking, boating, or aviation. Instead, eMap is designed to be an Electronic Map with a mid-size high resolution viewing screen. eMap can load (at the same time) any of the MapSource MetroGuide, WorldMap, USA Topo, and Roads and Recreation CD maps into its 8 or 16 megabyte optional memory. Note: MetroGuide maps are the most complete and most accurate electronic road maps for the USA that we have seen. For comparison of the different features in MapSource and MetroGuide maps go HERE. When using MetroGuide maps the eMap provides "RoadLock" whereby if you are within several hundreds of feet of a road and are heading generally in the direction of the roadway, your current position icon will "lock to the road" thus eliminating GPS errors. ( When used with any MapSource R&R or TOPO map, roadlock does not operate.) A major feature of v. 2.50 is that with roadlock, it will display each side road coming up in time to make a turn. This is helpful when looking for side streets in the DARK! With a MetroGuide map, you can FIND any of the following map features: waypoints, cities, freeway exits, Points of Interest, Street Addresses, and point to it on the map. With eMap, map data can be uploaded at 115 kbaud rate if your computer serial port supports this rate. eMap provides a high resolution (120x160 pixels and 1.7"x2.2") display which is easy to view in daylight or with the single level backlight at night. Lighted keys would be handy for night use, but eMap omits this feature. The case size is 5.5" x 2.37" x .8" (6x14x2 cm) which thickness is considerably less than any GPS we have reviewed. It makes a comfortable shirt pocket fit. The eMap is rated "water resistant" (IPX2). We would be apprehensive about the unit continuing to work if it got rained upon. Contents
|
Sponsored by: For information regarding advertising rates Click Here! |
Copyright© 1995-2012 MindSites Group / Privacy Policy
GeoCommunity™, Wireless Developer Network™, GIS Data Depot®, and Spatial News™
including all logos and other service marks
are registered trademarks and trade communities of
MindSites Group