Working with Databases

This chapter covers the use of databases in Garmin receivers. Only some Garmin receivers actually support and include databases so this chapter is specific to those units. Databases are of two types. There is text information that can be displayed to the user and there is graphical data that can be displayed on the map page. Generally there is also search capability to locate the information you wish. Note that Garmin receivers that support maps do not contain a kind of maps that you might be used to when comparing to traditional paper maps, instead they contain a database of vector data and create maps on the screen on the fly for you to use. These "vector maps" have a number of advantages for the user. Some of them are listed below:

Generally speaking, the text data stored in Garmin database can be viewed easily via the graphic representation on the map page. For example information on point of interest at a particular exit on a freeway can be found by selecting the exit symbol on the map. Some data may also be searched from the menu system. Except for the Jeppesen database (for use on aircraft) the Garmin databases are only available from Garmin or a Garmin dealer. There are no third party commercial sources for these maps or other data.

There is a noncommercial program called gpsmapper being developed by reverse engineering the database. This tool permits the user to build their own maps. Note that this requires a significant amount of work by the user. This program is not supported or approved by Garmin.

Table of Contents

City Databases

The city databases are really just a collection of items, similar to standard waypoints, that mark the location of cities. These can be useful for high level orientation when flying, or traveling on the highway. It is not clear exactly where in the city the waypoint depicts but it is likely the geographic center; as it clearly does no mark any prominent place. For non-mapping units there are 6 databases available and are selected when you buy the unit. They are not changeable or upgradeable. All of the databases include major cities (greater than 200,000 population) for the whole world and smaller cities, towns, and villages for the region of your choice. There are typically more that 22,000 locations included, sometimes a lot more (30,000 on the 12CX). The six regions are North America, South America, Europe, Africa, Asia, and South Pacific.

The city names are not subject to the standard 6 character limit of Garmin handhelds. They are shown on the map screen like user defined waypoints but cannot be used directly for navigation. If you want a city in a city database to be used as a goto destination or as part of a route it must be copied into the user waypoint memory. This is most easily done by displaying the city on the map page and then highlighting it using the pan option. Once highlighted you can hit to mark key or the goto followed by enter to create a user waypoint with the same data. In the case of goto you will also start navigating toward that waypoint. Since the city names are likely to be larger than 6 characters the gps automatically creates a short abbreviated name for the city.

To locate a particular city in the database you would use the "Find City" command from the main menu. Once selected you should enter the desired name as if you were entering a name for a waypoint. The first entry in the database that matches the name you entered will be displayed along with the state. If there are duplicates you can use the arrow keys to scroll until you reach the one you want. Alternately you can visually locate the city using the map screen and highlight it and press enter to select. Once selected you can check the distance to the city or between cities and a reference waypoint using the 'ref' section of the page. All underscores represents your current position or you can select any waypoint in your list. Once satisfied, press enter to display the great circle distance and a bearing to the city. If a city is displayed you can also press goto to automatically create a user waypoint at that location and begin navigating toward that location. The 'showmap' entry at the bottom of the screen can be used to display the city location on the map page.

Map screen display options for the city database (city setup) can be reached on the map page local menu (called Opt on some units). You can control exactly when cities will be displayed by setting the zoom level based on the city size. When you zoom out further than the set limit that size city will no longer be shown. The largest cities in the database are always displayed. In addition another copy of the find city command is on the map screen local menu.

Base Maps

Receivers that are capable of viewing maps always include a basemap with the unit which provides main road coverage and a collection of city locations similar to those described above. There several basemaps available on Garmin units. The original mapping receiver was the G-III. It came in two versions, an Americas version covering the North and South American continents and the International version that covered the rest of the world. These map choices were made at the time of purchase and were specific to where you bought your unit. The G-III pilot also had these choices for a base map. Later, when the G-III+ was released there was a new basemap that also included freeway exit information and is considerably newer than the original maps. This map is available on the III+, the 12Map, NavTalk, the Street Pilot Series, the emap, the GPS V, the 76Map, the Legend, the Vista, and some other mapping receivers. Originally this was only available in the Americas version but an Atlantic basemap was soon added to for all of the above units that provides more detailed coverage of Europe. Most recently a Pacific basemap was released which adds the data for most of the rest of the world. Like the original released maps, the basemap that is in the unit you purchase is dependent upon where the unit is purchased.

All of the basemaps include Country outlines and major city locations for the entire world. In addition they include more detailed information about the specific region covered by the unit you purchased. This information is stored in a rom and is not changeable or upgradeable. At one point the Americas data in the original III was revised so there are two versions of this unit as indicated by the map revision data on the opening screen. The newest of the GPS III version maps is also used in the Americas Street Pilot but is out of date compared to the GPS III Plus base maps.

All of the US coverage in the base maps is based on the census bureau tiger database. In the last year or two there have been many improvements in this database that are not reflected in the basemaps. Garmin has not disclosed the version of the tiger database that was used when making these maps. The original basemaps seem to be the level of the 1995 tiger database with the III+ seems to have the 1997 update. Coverage for the rest of the world comes from various sources with varying degrees of completeness and accuracy. You can expect some missing roads and some roads inaccurately represented in these databases.

Garmin specifies the coverage of the basemaps for the Americas to include:

The international version contains similar data. The Atlantic database contains detail for western europe that is similar to the additional detail shown above for the US and Canada. Similarly the Pacific database provides some increased detail for Australia and Eastern Pacific rim countries.

When Garmin decided to release half the world in a gps unit there had to be compromises. There is only so much room in one rom so they chose several ways to reduce the size of the database. First they decreased the detail. This is the most obvious method. Secondly they reduced the faithfulness to curves and jogs in the road. This reduces the number of points used to describe a road and thus reduces the total size of the database. A road description consists of these points connected by lines, hence the term vector database. Finally they reduced the number of bits used to describe the points themselves. Since data about the points is a floating point number you can simply reduce resolution by a bit or two and save significant amount of space in the rom. Garmin takes advantage of this by reducing the precision of the road data and they reduce the precision even more on the background lakes and shoreline data.

Since the data has been reduced in precision you should not depend on the locations for absolute accuracy. Garmin indicates this by displaying the word 'overzoom' just below the scale indicator on the map page. The word overzoom appears anytime you have set the map resolution beyond the accuracy of the map itself. You may still wish to do this since the accuracy of the gps itself is higher, but realize that the position relative to the map objects should be suspect. The overzoom indication was confusing to some folks so Garmin added an error circle. Basically this circle factors in your position accuracy (as indicated by your epe) and the map accuracy to display a circle of uncertainty. You are probably somewhere inside the circle as displayed on the map. If you turn the map display off (on units with this capability) then the circle will get much smaller as it will display the precision of the fix itself. By the way, this is just an estimate, you might still be outside the circle. The circle may be turned on or off as desired except on the emap where it is always on.

Loadable Maps and POI

Garmin provides a Points of Interest, database on all mapping units and a few of the newer non-mapping units. This section covers both kinds of units. For example, there are exit POI's in the basemap for loadable map units. An example of an exit POI is shown below (exit 225):

These can be reached by highlighting the small square showing the exit and hitting enter. Then use the keypad to select the item of interest and hit enter to display the POI's. These POI's includes many businesses within about 1/4 mile of the exit, including; restaurants, diesel/gas, hotels/lodging, overnight RV parking and dumps, campgrounds, truckstops, medical facilities, shopping and outlet malls, ATM's, and many more attractions.

Loadable Maps are supplied on a CDROM called a MapSource CD and are loadable via a program that is included on the CD. Often the program on the cd is out of date so you should visit the Garmin web site and download the latest version. This program can be used with mapping units and non-mapping units to upload and download tracks, routes, and waypoints however map databases can only be loaded into mapping capable units. In addition to the maps themselves the cdrom contains POI information to varying degrees based on which cdrom you purchase. MapSource CD's can be used to upload POI and mapping information to Garmin units that have memory set aside for this purpose. Use of the MapSource product is covered in a separate chapter. Adding maps via this program does not affect the basemap in any way except the presentation of information will favor the downloaded maps when present for the area you are viewing.


There are basically three completely different groups of MapSource cdrom data for road use. These include City Select, Metroguide, and Roads and Recreation. In addition there are some more specialized mapping products available such as Topo maps, Waterways and Lights for marine use, Fishing hotspots for specific Lake coverage, and Blue charts for serious marine use.

The Metroguide cdroms began originally as cartridge based maps in the USA are designed specifically for gps upload into handheld devices. The same cartridges are now available as blank ROM are can now be uploaded with maps from cdroms. The Metroguide maps are road and street level maps. Prior to version 5.0 this database was from ETAK (owned by TeleAtlas) but are currently using NavTech data. They are very accurate and contain a significant amount of POI data, primarily of commercial establishments, and street level addressing for most areas. In addition Garmin has designed specific features, such as road lock (where the gps position display locks to the road on the map) and POI search facilities. These maps cover the full US. Originally the ETAK maps were packaged in sections that were too large for most hand held units except the emap. The 3.0 and 4.0 versions have been released that have improved coverage and smaller segments permitting these to be used in all Garmin mapping receivers. The 4.0 version also includes routing information in the database and can be used with the Garmin V to provide directing automatic routing on the unit and with MapSource to provide automatic routing on the PC. The 5.0 version continues to offer automatic routing on the PC but not on the GPS V. In addition to mapping visual support these map databases provide street level address searching and next intersection information. They also provide the support necessary to have a unit lock onto a road and track your position with respect to that road.

The City Select maps are shipped with the GPS V product and are only usable on this handheld and the other autorouting units. These maps are provided by NavTech which is also the supplier of most of the maps that are used in the dedicated vehicle based systems. The original USA release only covered major cities and interconnect roads but the newest release covers the full USA with street level detail. It provides all of the features of the Metroguide line of products and adds information that is needed for the autorouter.

The last of the USA road map products is the R&R, Roads and Recreation, cdrom. It contains detailed street level data and recreation POI's. It also contains updates to the basemap freeway exit information. The street level data comes from the Tiger database which is the same source as is used on the base maps. However, in the case of the R&R cdrom it is the full database at full resolution. Note however that the Tiger database itself is not maintained to the same degree of accuracy as the TeleAtlas or NavTech databases of the same area, and due to the age of this release it has data in it that is even older than the base map data in some of the newest units. The resolution of this data can be observed by turning on the error circle. You will find the circle significantly smaller than the base map circle but, for USA data, it is larger than some of the other databases available from Garmin. The downloads are usually divided by counties and you can generally load several maps into the 1.4 Meg space of the older Garmin units.

Other US map cdroms include a topographic cdrom and most recently a marine database. The topographic cdrom is derived from USGS 100K data is is very precise, equaling or better than the TeleAtlas data, but can be rather old since USGS surveys are not done very often. In some case the data can be as old as 20 years or more. The topographic data for government maps are often updated via arial photographs so will often not include updates to man made objects. The topographic data includes elevation data and roads, but roads that are generally not named, and includes some trails. It is most useful for off-road and backpacking use. The maps contain the highest precision of any of the mapsource maps available for handhelds and rival the precision of Metroguide maps. The topo maps include everything that is on the R&R cdrom for the US except road names and freeway exit data. It includes many items not found in the R&R database such as good coverage of coastal navaids (sorry not inland), pipelines, airport runways, towers, and other physical features. It even includes some underwater contours.

Garmin has plans to release 24K Topo map detail for National Parks in the USA. Currently the Western United States in released. Note that the 100K and 24K desginations reflects that basic coverage of these maps but the actual data is vector and fully zoomable in both sets of maps.

There is a Waterways and Lights cdrom for the USA that includes improved coverage of outlines and navaid data for coastal and inland areas. There is very little data available from sources outside of Garmin as to what it contains. A future release is supposed to include some depth contours. See the marine navaid section below for more details on navaids. In addition there is a fishing hotspots cdrom that contains data for inland lakes.


The maps for Europe are all from NavTech and all provide the same level of road detail but differ in other respects. The City Select maps provide autorouting data on the GPS V (and other autorouting units) and on the PC while Metroguide maps only provide autorouting on the PC. Both provide street address and database searching. Finally the Roads and Recreation maps provide no autorouting but are the smallest files sizes. The R&R maps do not support the street address database lookup. Originally Metroguide and Roads and Recreation maps were sold on a country by country basis but the newer release has the entire continent in one set. City Select requires an unlock code for the various regions. One is supplied with the product but an additional unlock must be purchased for the rest of Europe.

Canada has maps similar to those of Europe and are from NavTech. Only major cities are covered but both the Metroguide and Road & Recreation are on the same cdrom so the user gets both sets. In addition there is an enhanced basemap that covers areas not covered in the NavTech maps.

Australia has a set up maps as well, also from NavTech and there is a city select map for South Africa. Other parts of the world are planned.

For areas outside the ones identified above a user can buy a cdrom containing the Worldmap. This is basically a collection of the various basemaps so that a user can have maps in the area of the world not covered in their particular basemap. This database is pretty old and contains about the same resolution of information that was found in the old G-III international version basemap for the whole world. It provides americas basemap level coverage including freeway exit data which is useful for international customers. It does provide coverage of road level data in areas not covered by any other mapsource maps to date. It has not be updated even to the level on the newer G-III+ atlantic version. It is probably better than nothing but not by much. Hopefully Garmin will update this with the newer data that is now available. It has the best source of worldwide coastal marine navaids and good coastal maps.


Garmin has made a recent commitment to update the Mapsource maps yearly and are beginning to deliver on this promise. You can view the maps on a per cdrom basis at the Garmin web site to determine if its contents is suitable for your area.

The gps receivers that support maps also support the ability to upload multiple maps simultaneously up to the limit of available memory. You can even upload maps from different mapsource cdroms. Each time you upload you must load all of the maps you want as you cannot add maps to an existing upload. If a map covers the same area as a basemap then it will automatically be used in lieu of the basemap when the gps determines that you are located in an area covered by the uploaded map. If there are two uploaded maps covering the same area then the results are less predictable. The receivers provide the ability to turn off the display of individual uploaded maps so that you can see the map you wish. Control of maps is done with the local menu on the map page. Select the mapsource info tab to display information on loaded maps and to select which ones should be displayed. The area and detail, including poi's, in a uploaded map is predetermined by software and is not adjustable by the user however, once loaded, you can adjust the display of this data.

You can search for cities on the maps using the "spell and find" command. It is located on the main menu under cities. You use it just like the find cities command described above in the city database section. If you wish to use a city as a destination in a route you must convert it to a standard waypoint as described in that section. There is an option of the spell and find local menu that can be used to display the city size or use it as a reference to measure distance. To view any services or POI's you would select them from the map page.

The emap and newer units have a more sophisticated search capability using a dedicated find key. Pressing find will bring up a menu that permits you to find waypoints, cities, or freeway exits. If you have a MapSource database loaded you will also be able to search for poi data. If you have an optional metroguide map or city select map installed you can also find more points of interest, intersections and addresses. Select the menu item you wish to brings up the selection screen. Selection screens can have a local menu that permits switching between find by name and find nearest. Use the arrow keys to select the one you want or to enter the name of the one you want and press enter to find more information about the item. Exit data (and POI data for installed cartridges) has more menus to permit selection of an individual point of interest. Once the poi is selected you can hit enter to find information about it including directions to find it from the freeway exit or its address. Once an item is selected it can be the target of a goto by selecting this entry from the screen. Unlike other handheld units the found items do not have to be converted to waypoints to use them for navigation. You can, however, use the local menu to convert them to waypoints if you wish.


The Jeppesen database is a service that contains a worldwide database of information needed by pilots. A Jeppesen database is supplied with the III Pilot and can be updated either with one time upgrades or through a subscription service. These can be obtained from Garmin or directly through Jeppesen. The current effective date for the database in the unit is shown on opening database screen.

The Jeppesen database contains information on airports, runways, communications frequencies, VORs, NDBs, intersections and airspace boundaries. This information is available on the map page and from the waypoints menu choice on the main menu. In addition certain features of the III Pilot can take advantage of the data in the Jeppesen database. For example, the vertical navigation feature can use the airport location and altitude data. (See the navigation chapter for a discussion of vertical navigation.)

To access the database information from the map screen use the rocker keypad to place the panning cursor over the icon containing the desired information. The identifier will be highlighted. Hit enter to view the information. If an airport is selected you will have a set of tabs that can be used to select airport, runway, or communications pages. If the cursor is in a open area of the map you will get airspace information if the enter key is pressed.

To access the database from the main menu hit menu twice as normal, highlight 'Waypoints' and press enter. A series of tabs will appear that lets you select from airports, runways, comm frequencies, VORs, NDBs, intersections, or user-entered waypoints. Select the category with the rocker keypad. The information can be search by identifier or, in the case of airports, VORs, and NDBs, by facility name or city. Highlight the appropriate field, press enter and supply any needed name by use the rocker keypad.

The map page contains icons representing the Jeppesen data and also shows the airspace boundaries graphically. This information can be turned on or off using the map display menu. The available settings include Aviation DAta on the map menu, large/medium/small airports on the Apt menu, VORs/NDBs/intersections on the Nav menu, Controlled airspace on the CTRL tab, and Special Use airspace on the SUA tab. The highway display also shows the airports that may appear along the route you are traveling.

The 9 nearest airports can be located using the GOTO/NRST key. Press and hold the key until the nearest page appears and then select the airports tab. You can find information about the airport by selecting the entry to view it. You can also highlight the desired airport and press the GOTO key followed by ENTER to designate this airport as you desired destination.

Specific information in the Jeppesen database includes:

Data that can be displayed graphically such as locations and airspace boundaries with be shown on the map page except runways have a special graphic display as part of runway information.

Jeppesen data can also drive the alarms such that you are warned when you change from one control space to another or entry into a restricted area, proximity to control towers, etc.

If there are conflicts between the jeppesen names and user defined waypoint names the III pilot will bring of a list of duplicate names so that you can choose which one you want.

Marine Navaids

Navaids are the aids to navigation that are used in Marine applications. (Air navaids in included in the Jeppesen data shown above.) These include such things as navigation buoys, beacons, fog horns, and light houses. Of the handheld units covered in this manual only the Garmin 48 includes navaids as part of the base product. Most of the information in this section is based on this unit. However, the units that support loadable POI information also support loadable navigation aid information. The Garmin 48 is updateable using the Waterways and Lights cdrom. The 48 is divided by region exactly the same way as the city databases described above. On mapping units the navaid data is treated similarly to the POI information available on the 'Roads and Recreation' CD's and the 'WaterWays and Lights' CD.

The display of navaid data on the map page is under control of the local menu navaid setup. You can control exactly when objects appear based on the zoom level. Control is based on the range of the object. Some Garmin units do not distinguish navaids from other poi's and may not have this feature. Navaid labels are also configurable from navaid setup. Unlike the city database navaids can be treated like a user waypoint on the 48 but must be translated to user waypoints on other units to use them for navigation or alarms.

Navaid icons on the G-48 are shown below:

The label on the navaid is coded to supply information about the navaid itself. The following is the decode of the label data:

The new mapsource "WaterWays and Lights" cdrom, the "topo" cdrom, the older "Roads and Recreation" cdrom and the "Worldmap" cdrom contain navaids as well. These include some wrecks and other potential obstruction data not included on the G-48. They can only upload navaids as part of their generally mapping uploads for mapping receivers. Coverage for the W&L cdrom includes inland bodies of water as well as coastal areas. It provides coastal and lake outlines and navaid data. Other cdroms have differing coverage depending on the map cdrom. Check the map section above for details on coverage. The types of navaids available on the cdroms include all of the types shown above for the G-48 plus ship wreck, rocks and other hazards to navigation. The figure below shows the icons and the information they represent.

00/5/03 initial release
00/5/10 added more data on the maps and navaids
00/7/7 updated for emap data
02/7/23 updated for GPS V and mapping products updates
03/7/3 updates for new Metroguide maps.

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