Garmin's GPS-III Road Map GPS Product Review
By Joe Mehaffey and Jack Yeazel
    (2 January 1999)

Note:  This model has been discontinued and is not the G-III+ model.  (Click HERE for the G-III + review.)
When  most  people  get  their first  GPS  receiver, they ask, "Where's the MAP?"   Garmin answers that question with their GPS-III  receiver.  The GPS-III (G3) is Garmin's  new  handheld  12 channel PARALLEL GPS with built-in maps.  The G3 comes in several variants, an  Americas road map version  and  an  International version  and a "pilot" model with aviation features in both  road map  versions.  This review will focus on the Americas  (includes USA) road map edition.  Comparison G-III to Lowrance GM100 and StreetPilot maps can be seen HERE.

The G3 was the first consumer GPS model to incorporate  extensive (but not nearly  exhaustive)  road  maps  of  the  USA and Canada INCLUDED in the basic unit.  It is joined now by the Lowrance GM-100 (now with user uploadable maps), the Garmin StreetPilot, and the new G-III PLUS (with uploadable maps).  The G3  display  is much smaller than the map display on a laptop or  even a palmtop,  but we find the maps both accurate and useful.

GPS-III Feature Highlights
The  G3  is packaged in the same case as the  GPS-II+.   However, the  differences between the two units are substantial.   The  G3 provides the usual Garmin G-II+ features as a base,  but the user interface has been extensively redesigned and for the better.  In addition,   the G3 has major enhancements including  an  overview map of the world plus maps of  USA interstate, national,  primary and secondary state highways,  cities,  larger towns,  waterways, rivers,  and  coastlines.  (Note:  See text at the  end  of  this review  for more information on map content vs areas.)  ALL  maps are  included in its internal memory.  There is no provision  for users to upload maps into the G3. however,  uploadable maps are available with the G3 PLUS version. (Note:  The G3 is *NOT* upgradable to the G3 PLUS.)  Internal maps are registered to WGS-84,  and  the setting of the datum for NMEA output has no effect on the accuracy of the internal maps.

Additional  features beyond the G-II+ include:
A  [100x160]  high  resolution 4 gray  scale  display,  a  world overview map display,  road map display,  trip computer (includes maximum  speed,  average  speed,  trip  timer, odometers,  etc.)  Almost all numeric displays fields  are user selectable.

A  "3D"  highway page is another new and  innovative  feature  to provide  steering  directions along routes or  toward  waypoints.  Roads  curve  to the right or left as appropriate  and  "waypoint  signs"  show  directions and progress along a route.   Forty  six ICONS  are  available in the G3 to identify  waypoints  and  mark routes.   A large diameter calibrated compass rose page  provides bearing,  course and other information.   The battery  meter  can be  set to alkaline,  lithium, or NiCad types.  Alkaline  battery life  in the G3 is about 24  hours, the same as for  the  G-II+.  (Older G-III receivers had battery life of 8 to  10  hours.)  With version 2.06 firmware,  Garmin has introduced a  new power save mode into the G-3.  An automatically reset battery use timer  is  provided  to  permit  comparison of battery lifetimes.  Eleven independent  track logs can be used to store an assortment of user tracks.

Street  pricing  of  the  G3 is about  US$300  for  the  Americas version.  One UK vendor's price for the International version  is  UKP300 inc. VAT.   Current Garmin plans are for USA dealers NOT to be  able  to  sell the G3  International  version  apparently  to protect their International dealers.

Features and Operation
Basic functions in the G3 mimic those in the earlier G-II+,   but many  functions are implemented with enhanced features and  users may  customize almost every data display field.  The G3  incorporates  the same 12 channel PARALLEL GPS receiver design  used  in the  G-12XL and G-II+ products.  Like these,  the G3 locks on  to the  SV  signals  quickly.    "Warm starts"  are  typical  in  12 seconds.   "Cold  Starts" after 3 hours off time take  50  to  70 seconds.   In  Autolocate  after a 1000 mile UPS  trip,   the  G3 locked  on in less than five minutes.   Specifications are  "warm start"  ,  15 seconds,  "cold start" 45 seconds,  "Autolocate"  5 minutes.   These  times  are  typical  of  12  channel   parallel receivers  in  the clear and not moving.  This  is  significantly faster  than  any of the single channel scanning  type  receivers such as the G-45XL and the M-4000XL (dual channel version) but  a bit  slower  than the G-II+ in our measurements.  If  the  G3  is shielded from SVs (and thus unable to lock) for a time,  the unit will request initialization.  With   Garmin's "Initialize by Map" feature,   you do not need your approximate lon/lat to  speed  up the initial lock when you move more than 300 miles with the  unit off.   Simply point at your approximate location on the  map  and press "enter".

The  G3's specification for position accuracy is 100 meters  with SA,   15 meters exclusive of SA and 5 meters with  suitable  DGPS correction signals.  These are the  same as the G-12XL and the G-II+.   This  specification is considerably better than  the  DGPS specs available with  the Eagle Explorer and most low cost single and dual channel multiplexing systems.   For instance,  the  DGPS error  specification  for   the G-45XL is 10 meters.  For the  EE it  is 22 meters.   The G3 appears to have enhanced position  and velocity filtering as compared with the G-12xl/G-II+ as a  result of  improved  the  data filtering  algorithms.   We  notice  more directional stability in the compass display when walking as well as  somewhat  less variation of indicated velocity.  The  G3  has Garmin's  "dead  reckoning"  feature  which,   upon  loss  of  SV signals,  will  project a course for 30 seconds  along  the  last valid heading.  This reduces the impact of momentary loss of  GPS signals at underpasses,  tree cover,  and city buildings.

Position averaging is available in the G3 to improve the accuracy of  individual  waypoints.   The G3, like the G-12  (and  others) uses an over determined solution when more than 4 SVs are locked. This produces somewhat higher accuracy than units which use  only the  best four SVs.  Garmin uses an algorithm that gives  varying "authority" to measurements from SVs depending on their geometry,  and  other factors.  This may be responsible for  the  relatively good accuracy of Garmin's 12 channel parallel receivers.

The G3 operates from 4 AA batteries or from external power in the range  of 10 to 32 volts DC.  External current draw at  12  volts input  on  my unit is about 65ma (light off).  Battery  drain  is about  150ma  (light  off).    Memory  backup  power  drawn  from batteries when the unit is off is about 100 microamps.  (Note:  Garmin recommends installing fresh batteries in your GPS prior to storage.)  Eight  to ten  hours is specified as the AA battery life with  Duracell  or similar  batteries.   Newer G-III receivers achieve about 20 hours  of  operation  with Toshiba AA alkaline cells.   (Note:  Older units produced before September 1998 typically achieve 16+ hours of battery life or 10 hours for  earliest units.)  The increase in battery life has been the result of several improvements in current drain of circuit components.   The Electroluminescent display lighting has a rated design life  of  100,000  hours.  Newest G3 shut down  when  the  internal battery voltage goes below 4.00vdc. (Was 4.50 volts with earlier units.)   With the installation of ver 2.06 firmware,  a "power save" mode can be used to extend battery life in some situations.

The  data/power cable used is the same as the Garmin  G-45/12/II+ units.   The  external antenna connector,  a BNC coax  jack,  is located on the right-rear of the unit just behind the keys.  The BNC jack is powered and has a current limit rated at  50ma to protect  the unit from shorts on the antenna cable.   (Note:   We measured 90ma short circuit current on our unit.)   However,  the standard  antenna  is passive.   We measured 5.54  volts  on  the
connector with antenna load =30ma and  battery voltage  measuring 5.71vdc on the G3's voltage monitor.  The Garmin GA-26  amplified antenna and the MAGELLAN M-4000 amplified antenna both work  with the G3.   Other amplified GPS antennas, including the Lowe unit, will work as well.

The  G3  puts out only the NMEA protocol NMEA-0183  ver  2.0  and accepts  RTCM-0104.  Other proprietary (GARM/GARM) sentences  are input/output as well.  With version 2.07 firmware,  it is no longer necessary to switch between NMEA and GARM/GARM for tracking vs upload/download with many software systems which can use the Garmin "HOST" mode.    DGPS signals in  the RTCM-104  format are accepted.  Anytime NMEA output is  selected, the baud rate of both the input and output serial port is set  to 4800 baud.  RTCM (DGPS) alone can use baud rates of 300 to  9600.  A setup screen permits selection of the I/O combination needed by a particular application.

Operating temperature range is specified as -15C to +70C.  Unique in  their  class,   the  G3,  G-II+,  and the  G-12XL  are  rated submersible to one meter per IEC529 IPX(7).  The maximum altitude rating is 60,000ft and speed maximum is 999 knots.

Feature Details
The  G3  has a number of features and displays that  are  useful.
These include:
(&= Feature essentially identical in the G-II+)
(#= New (or significantly modified) Feature not in the G-II+.)

#a)  A unique "3D" highway display screen shows the highway ahead including coming curves and turns.  A tape "compass"  provides heading.  Four digital data fields may have user  selectable displays including: altitude, avg. speed,  bearing,  course, dist  to destination, dist to next waypoint,  ETA at  dest., ETA  at  next waypoint,  max speed,   off  course  distance, course pointer,  speed,  time of day,  time to  destination, time to next waypoint,  steer to course,  track,  trip odom, trip  timer,   turn  indicator,   user  timer,   VMG,    and destination  waypoint.   A GOTO waypoint is displayed  in  a separate field on the highway display.

#b)  A compass rose display screen shows direction of travel  and has  an  arrow pointing to the next waypoint.   This  screen provides four user selectable numeric data fields which may display  any four of the following:  altitude,   avg  speed, bearing,   course,   dist  to  destination,   dist  to  next waypoint, ETA at dest,  ETA at next,  max speed, off course distance,  speed,  sunrise time,  sunset time,  time of  day,  time to dest,  time to next,  bearing  to  course, track, trip odom, trip timer, turn indicator, user timer,  VMG, Destination (waypoint),  Next (waypoint).  The display  can  show a LARGE letter data fields  and  a  small compass  rose  OR  a LARGE compass  rose  and  smaller  data fields.

#c)  A  moving map display is provided to plot your  course  over ground.  (These comments apply to the G3 Americas  version.)   Map data includes an overview map of  the  world plus  maps  of   USA  interstate,  national,   primary   and secondary state highways,  cities,  larger towns, waterways, rivers,  and coastlines in its internal memory.  Outside  of Canada,   Mexico and the USA,  maps have the same  features,  but are generally less detailed.  In addition, four optional fields on the map display can display four of the  following user  selectable  fields:  altitude,  avg  speed,   bearing,  course,   dist to destination,  dist to next waypoint,   ETA at  dest,   ETA at next,  max speed,  off  course,   bearing pointer,  speed,  time of day,  time to dest,  time to  next waypoint,  steer to course,  track,  trip odom,  trip timer,  turn  indicator,  user timer,  VMG,   destination  waypoint,  next waypoint.  Waypoints saved in the machine are displayed on the moving map page as they come within range of the  map scale  selected.  Note: The map detail is quite  impressive,  but  it  does NOT show residential streets or  (in  general) city  streets excepting numbered highways and  major  roads.   It is NOT a replacement for Street Atlas 4 or similar.   The map screen has pan and zoom and scales from 500 feet to 3000 miles  (screen  width).  Map operation is  quite  intuitive. The Lowrance GM-100 and the Garmin G3 PLUS with user uploadable from CDROM maps (and StreetPilot with Cartridge Maps) are available for those who want residential street level detail.

You  can "point" at any point on the map  with  the  cursor, and  the  distance and bearing to that  waypoint  from  your present position will be displayed.  You can also "mark" and store  a  new waypoint by moving the cursor to  the  desired position  on  the map and pressing the MARK  key.   You  can generate  ROUTES directly from the map by either  "clicking"  on  a series of existing waypoints OR by  just  sequentially "clicking" on a series of map locations.  Routes can also be generated from a series of cataloged waypoints as in the  G-II+.   There appear to be 7 layers of map  detail.

The  map may be set to  north up, or current track up.   The map  display  provides an array of user  customize  features  such  as  map orientation,  autozoom,  land  data  (off/on), map  line width selection,  text size selection,  city  size selection,  and similar.   The map screen also supports zoom and  pan  and  "measure  distance"  features.   On  the  G3,  waypoints  can have one of 47 symbols such as boat,  house, gas  pump,  etc.  When you are moving,  an  "arrow"  pointer shows  your  direction and leaves a "cookie  trail"  showing your track.  Map accuracy is very  good,  but not perfect.

#d)  The  G3 has a TRIP COMPUTER feature page.  This page  has  a trip odometer,  trip timer,  maximum speed,  odometer,   and average speed displays.  These displays may be independently or simultaneously reset.

&e)  A simulator feature provides display of simulated motion and simultaneously  outputs  simulated  tracking  data  to  your computer  for  test  of mapping  software,   data  gathering simulations  and  such.   However,   the  simulated  present position  cannot be changed as in the G-II+.  If you are  in simulator mode and turn off power,  a power ON automatically restores normal mode operation.  (Note:  A workaround on our website tells you how to change the simulator initial position.)

#f)  A  screen back lighting timer permits setting the  backlight to  None, 15, 30, 60, 120,  and 240 seconds.    Backlighting is adjustable in three steps on the G3. The backlighting  is uniform and tinted green and the display at night is easy to read.   The  display has four shades of  gray  with  100x160 pixel resolution.  With ver 2.06 firmware, backlighting will not timeout when the G3 is operated on external power.

&g)  There  is no audible warning tone for alarms or warnings  on the G3.

&h)  A  message  screen  pops  up to  show  system  warnings  and messages.    These  include  such  things   as   approaching waypoint,  no DGPS position,  poor gps coverage, and battery is low.  The total number of such advisory messages is 26.

#i)  When  the unit is powered ON,  a Garmin introductory  screen comes  on  followed by a "land data is provided  only  as  a general  reference  to your surroundings" page.   Then,  (no manual intervention necessary),  the usual  satellite status page  comes  up.   It displays a "fuel"   or  battery  gauge showing  battery  remaining,  and  a  "compass"  display  of satellite  numbers  (1  to 32) in  view  along  with  signal strength bars for each satellite potentially in view (up  to 12).   If the unit is powered from an external source,   the "fuel"  gauge bar disappears.  The signal strength bars  are hollow if the GPS has found the SV and has not yet downloaded  ephemeris data and changes to solid black when  data  is  received from each satellite in turn.  Each signal  strength bar is marked with the associated satellite number.  On  the polar  plot,  SV numbers are black on white when not  locked and  white on black when locked.  When LOCK occurs,  the  G3 automatically goes to the map page.

#j)  Waypoints  may  be named with a six character  name  plus  a symbol  (boat,   gas  pump,   house,   etc.)  which  may  be selected  from  a  library of 46 symbols.   If  you  have  a "mysterious"  waypoint in your list,  select it,  hit  menu, select  SHOW  MAP  and the map will jump  to  that  waypoint location so you can identify it.

&k)  The  G3  has a new track log system.  One ACTIVE  track  log with  1900 log points where track log points  are  initially  recorded  and  Ten additional "compressed"  track  logs  are provided in the G3.   The compressed logs have a maximum  of 250  log  points and the active track is compressed  into  a save  file.  Saved logs are similar to routes in the  method in which they are stored AND these saved logs can be used in TracBack when desired.  Each saved log can be named with  up to 13 characters. By default, the log will be named with the date  it  was  saved. Each saved  log  can  be  individually deleted, or TracBacked.

&l)  TracBack is a feature shared with the G-12XL and the  G-II+.  If  a user goes out along a random track and then  wants  to return   to his point of origin,  he may  select,  TRACBACK,  and  the  G3 will compute up to 30 "best" waypoints  for   a  return  path and store them as a Route.  When  TRACBACK   is activated,  the unit will route using the computed  information  in the Route.  In the G3,  you can TracBack using  any of  the  eleven  compressed track  logs.   Jack  tested  the compression algorithm and found it quite accurate.  It  will duplicate even a small circle in the uncompressed track.

&m)  The G-II+ accepts the RTCM-104 version 2.0  DGPS  correction format.   The  GPS can control the frequency of  the  Garmin GBR-21  or other Starlink compatible DGPS receivers when  it is  set to the RTCM/NMEA mode.  (For the Garmin GBR-21  DGPS receiver,  you must connect the NMEA output to the DGPS  Rx,  but  you  can  also use the G3's  serial   output  for  your computer's  serial  port input.  In such case,   you  cannot upload/download data to the G3.)  DGPS beacon frequency  and signal strength will display on the G3 when DGPS activity is present on the RTCM input.  Note:  The NMEA I/O baud rate is ALWAYS  4800  baud on the G3  EXCEPT that in  RTCM-104  only mode,   (no NMEA output),  9600, 4800, 2400, 1200, 600,  and  300  baud  are  selectable.  This could  be  a  problem  for simultaneous  DGPS/NMEA operation since some DGPS  receivers will  not output at 4800 baud,  which is the only speed  you can  get with RTCM/NMEA.  Garmin says that all  of  Garmin's DGPS  ready  GPS  receivers are  compatible  with  all  DGPS receivers  which output RTCM SC104 version 2.0 data  streams within  the above limitation.  Alert messages (but no  beeps  on the G3) alarm  DGPS signal failure after about 15 seconds when that mode is enabled.

&n)  External   I/O  signal  modes  available  are:    NMEA/NONE, RTCM/NMEA,   GRMN/GRMN,  and RTCM/NONE.  If NMEA is  one  of the  selections,  the baud rate is automatically 4800  baud. NMEA $GP sentence output list for the G3 is:  BOD, GGA, GLL, GSA,  GSU,  RMB,  RMC, RTE, and WPL.  BOD  and  GLL  are  in addition to those in the G-12xl. With ver 2.06 firmware, the new PVT mode exists such that  with  proper software,  it is no longer necessary to manually  change  from  NMEA  to GARM mode.

&o)  No  Waypoint Proximity Alarm feature is provided on  the  G3 (as is present on the G-12XL) as the G3 has no alarm beeper.  System  setup has an ALARM CLOCK,  ARRIVAL ALARM,   and  OFF COURSE ALARM,  but these alarms only produce screen messages and so are of limited value.

&p)  The  user  may select a Magnetic heading reference  or  true north or User Selectable reference as required.

&q)  The G-3 has 107 built in map datums plus the capability  for users to set in their own datum settings.

&r)  USER GRIDS are supported in the G3 beginning with ver 2.05 firmware.  USER DATUMS are supported in all versions.

#s)  If the ENTER key is pressed and held when the unit is turned ON,  an undocumented test screen is activated which incidentally  measures  battery  voltage.   In  addition,   Battery voltage and an AUTOMATICALLY RESETTING battery timer may  be configured in the user optional data fields on the  position page.   The  "TIMERS"  page  under  system  setup   provides readouts  for  the USER TIMER,  BATTERY USAGE  TIMER,  USAGE SINCE MIDNIGHT TIMER and SINCE FACTORY RESET TIMER.

&t)  The G3 provides 500 user waypoints.  These waypoints may  be organized into twenty ROUTES (plus one TracBack route)  with 30  waypoints each.  The G3 has a ROUTE function similar  to the  G12xl  and  the  G-II+.  Twenty  routes  of  up  to  30 waypoints  each may be input by the user.  The G3  does  NOT have  the feature of being able to add a new waypoint  to  a route during the input of a new waypoint as was provided  in the  G-12xl  and G-II+. When navigating a  ROUTE,   as  each  waypoint  is passed,  the G3 automatically switches  to  the next waypoint in the route list.  Routes may be inverted  to return  along a path in the reverse direction.  A route  may be  copied  to  a new route and renamed.    If  a  route  is activated  when  your location is somewhere in  the  middle,  the nearest waypoint will be selected as the starting  point of the route.  If you are on a route and do a GoTo,  the  G3 will take you to the GoTo waypoint and then resume  navigating along an active route.

&u)  The G3 has dedicated ZOOM in/out buttons on the front panel.  This  permits  easy  expansion or  contraction  of  the  map display with a single keystroke.

#v)  The  G3  offers a waypoint symbol  feature  for  pictorially  identifying  waypoints.   This feature permits the  user  to show  such objects as anchors,  boats,  gas pumps,   houses,  cars,  fish, etc.  (forty seven different icons) to  further identify waypoints on the map display.

&y)  A "Delete By Symbol" feature permits deleting all  waypoints of a class.  This has been enhanced in ver 2.06 so that when waypoints are deleted by group, first the waypoints NOT in a Route are deleted and then the user can option to delete any additional waypoints as may be included in routes.  TracBack waypoints may be deleted in the G3  as a "class".

&z)  The G3 offers the ability (like the G-II/II+) of being  able to operate its display in the horizontal or vertical format.  This is convenient for automobile dash operation.

aa)  With ver 2.06 firmware,  the G3 will automatically shut down when external power is removed to avoid running down batteries.

bb)  The G3 with version 2.06 firmware  has  an "accuracy circle" around the current position to give an indication of current GPS position accuracy.  This is an ESTIMATE only.

cc)  Version 2.07 firmware corrected a number of minor  bugs  and is recommended for retrofit into older units.

Other:   We note that the G3 draws only about 100 microamps  from the AA battery in OFF mode whether or not the external power is connected.  In storage, this small drain will not deplete the batteries for years.

Subjective Observations of Performance (These tests were run on a version 2.01 firmware model.)

Jack  Yeazel  and I  have tested the G3 on the road  and  in  the field.  Our G3 has worked without a flaw that either of us  could find.   We uploaded and downloaded waypoints, tracks  and  routes using  Waypoint+(W95), and G7to..(DOS).  We tried it out on  SA4, Delorme MapExpert 2,  Precision Mapping 3,  Vista,  AutoRoute  5.  No problems found.   (Some upload/download programs will  require later releases for all of the new G3 functions to upload/download
properly.   Examples:  46  icons, the Active  Route  and  the  10 compressed  track  logs  in the G3 require  updated  versions  of upload/download software.)  Note:  We do not suggest that we have tried all features of all programs with the G3.  All map programs which  specified a NMEA-0183 ver 2.0 data stream as input  worked properly with the G3.

We  compared  the  G3 with the G-12XL and  the  G-II+.    The  G3 performed  on a par with the G-12XL and the EE in every test  for lock   stability,   multipath  performance,   re-lock  after   an underpass,  and ability to suddenly change direction without loss of  lock.   As with the G-II+, G-12XL and the EE,  we  were  very impressed at the speed  the G3 responded to changes in direction.

At  about 4mph,  the G3 would complete a change of  direction  in about  20  feet.  Previously we found with the  G-II+,  about  15 feet,   G-45 about 50ft,  and the M-4000,  about 60ft.  We  noted better low (and high) speed stability of the displayed speed.  At low speeds,  the compass display was noticeably more stable  than the G-II+ and the G-12xl's similar displays and the slightly more sluggish  response  in  low speed turns results  from  the  added
filtering  in  the G3.    The G3 laid down smooth tracks  on  our highway  maps during all tests.  No gaps,  jumps,  etc., (The  G3 has  data  smoothing  like the G-12xl and the  G-II+.)    Our  G3 included the vibration fix Garmin previously installed in the  G-II+.

We  noted that both the G3 (along with the G-12XL and the  G-II+) have a form of "dead reckoning" for moments when signal  dropouts occur.   For instance,  if the G-II+ is tracking along  and  just before a sharp turn you invert it and block its antenna,  it will continue  to  track  straight  for about  30  seconds.   It  also provides  a very good data smoothing filter to throw  out  random fixes  that are way off track.  This results in an  exceptionally
smooth  track  on  a moving map display even  when  multipath  is present.  Even with this filter,  there was no overshoot apparent during  quick  stops,  sharp turns,  and similar  maneuvers  when normal continuous tracking was taking place.

Performance under tree cover was about the same as the G-II+,  G-12XL and the EE and we rate that as very good.  We noted that the G-3  and G-II+ were considerably less sensitive  to  interference from the Eagle Explorer than is the G-12XL.  However,  all  three units  show reduced sensitivity when placed within a few feet  of Jack's cellular telephone.

We  found the display controls easy to learn and use.   The  menu system  and arrangement is considerably improved over the  *good* arrangement in the G-II+.  The G3 has many additional features as compared  with  the G-II+,  but the reorganization of  menus  and functions  make  it (we think) easier and more intuitive  to  use than the G-II+.

Our  overall  impressions  are  that  the  G3  is  a  substantial improvement in features and performance beyond the G-12XL and the G-II+ even discounting the new built in map features.

We  used two Toshiba 430CDT laptop computers running  moving  map software  during  our  tests.   The  comparison  gps  units  were operated on the dash in front of the driver (G3) and with the  G-II+  on the dash in front of the passenger.    The  laptops  with Moving  Map Software were used to log tracks,   "cookie  trails",  and operation for comparison.

Since  the  G3,  G-12XL and the G-II+ use the same  receiver  and exhibited  essentially  identical  tracking  performance  in  our tests,   we  did not perform the extensive field trials  we  made with  the  G-12XL,   EE, and others.   For  more  information  on tracking  results with our testing of the G-12XL,  and the  G-II+ see our reviews at:

If  anyone  has any additions,  questions,   suggestions,   error corrections  other comments,  please feel free to Email  Jack  or Joe.

Joe Mehaffey
Jack Yeazel
Other information:

  Model 010-00126-00

The  GPS  III,  Americas version,  includes  the  United  States, Alaska, Canada, Mexico, Central and South America, and covers  an area  from  W180  to W30 Longitude, S60  to  N75  Latitude.  Also included is a high-level worldwide map with political  boundaries
and  major  cities.  The standard map coverage for  the  Americas version includes:
     1)   Oceans, rivers and lakes (greater than 30 sq. miles)
     2)   Principal  cities and a small number of smaller  cities and towns
     3)   Major interstates and principal highways
     4)   Political boundaries (state and international borders)

A.  United States:  In addition to the standard map coverage, USA coverage  also includes:
     1)   Small lakes, major streams and rivers
     2)   Principal urban areas (including Alaska and Hawaii)
     3)   Railroads
     4)   National  and State level roads, plus some local  roads in or near urban areas
     5)   More detailed coastline
     6)   Small cities and towns

B.  Alaska:   In  addition to the standard map  coverage,  Alaska coverage also includes:
     1)   National  and State level roads, plus some local  roads in or near urban areas
     2)   Lakes greater than 5 square miles
     3)   Small cities and towns
     4)   Railroads

C.  Canada:   In addition to the standard map coverage,  Canadian coverage  also includes:
     1)   Lakes greater than 5 square miles-Southern Canada
     2)   Lakes greater than 10 square miles-Central Canada
     3)   Railroads

D.  Mexico,  Central and South America:
     1)   Standard Map Coverage


The GPS III,   International  version,  includes  Europe,   Asia, Africa, Australia, and Oceania, and covers an area from W30  to  E180 Longitude,  S60 to  N75  Latitude.   Also included  is a high-level worldwide map with  political boundaries and major cities and a portion of the  South Pacific.   The standard map coverage for  the  International basemap includes:
     1)   Oceans, rivers and lakes (greater than 30 sq. miles)
     2)   Principal  cities and a small amount of smaller  cities and towns
     3)   Major   motorways  and/or  interstates  and   principal highways
     4)   Political boundaries (state and international borders)

A.  Western  Europe,  South Africa, Australia, and  Oceania:
     In addition to the standard map coverage, it also includes:
     1)   Small lakes, major streams and rivers
     2)   Urban areas
     3)   Railroads
     4)   Regional arterial roadways
     5)   Small cities and towns

B.  Southeast Asia, China and Japan:  In addition to the standard map coverage, it also includes:
     1)   Lakes greater than 10 square miles
     2)   Large urban areas
     3)   Small cities and towns

Note:   The GPS-III-Pilot versions (Americas  and  International) have  the  same  map  data as is furnished  on  the  standard  G3 versions,   but the features are not identical.  In the  AMERICAS version,   we  noted that the maps in South America  are  not  as complete  as  in  North America particularly  as  to  road  maps.  Garmin's Statement on the reason that this is true follows:

Quote from Garmin follows:
* Map data on the G3 for areas outside the USA will almost always be of less detail than in the USA. This is because electronic map data for the USA and to a lesser extent for Canada and Mexico  is readily available and free or very low cost. Virtually all  other countries  around the world charge for this type of data  if  you can get it at all. Garmin had difficult decisions to make as  far as what data to purchase,  what to digitize our selves, and  what
to  leave  out.  We did the best we could  given  the  cost,  and potential customer base to pay for our efforts.
End of Garmin Quote

Features  we found "missing" in the G-III receiver and  ver  2.00 firmware as compared with the G-II+ are as follows:
1.   The  Pan Keys are disabled after jumping map to a  Waypoint.  It  requires  panning across the US to get  near  a  distant Waypoint.  (The Pan keys are enabled after jumping map to  a Routepoint.)
2.   Automatic  Route  creation  with  the  "Mark"  key  is   not available.  Marked waypoints must be selected by  "spelling" the  waypoint  name for each waypoint to be  included  in  a  Route.  (A work-around is to use the New Route selection and click on map waypoints to create a Route.)
3.   The  G-III battery life is 10 hours as compared to 24  hours in the G-II+.  (Longer battery life of about 16 hours is achieved by later models of the G-III.)