Working with Autorouting Garmin Receivers

Autorouting is a feature where you can simply request a destination and the gps receiver will calculate the path to the destination and guide the user to the destination with explicit turn data. The destination itself may have been the result of a search of the database based on an address. Among the handheld receivers released from Garmin only the GPS V can actually perform autorouting on the receiver itself. In order for autorouting to work the receiver needs a map of all of the roads that are available and the database used to produce the map requires much more data than just the connections between the turns. For example it needs to know if the street is a one way street, if left turns, or for that matter if any turns, are permitted at a give intersection, and much more very specific routing data. For this reason, a receiver that supports autorouting will not be able to autoroute without a suitable map database. In addition it needs to know additional data to make an informed opinion on what might be the best route to use when there are multiple choices. The speed limit for each segment of the road is an example of this kind of information. Freeway interchanges make the routing job even worse since the turn is often in a different direction that the final desired direction. Given the amount of complicated calculations it is pretty amazing that any handheld can do a decent job of computing a route automatically.

While only the GPS V can do autorouting on the unit itself any of the Garmin handheld receivers can provide navigation for a route generated externally and then downloaded to the unit via a suitable program. For example the Garmin Mapsource program can use the same maps that are downloaded to a mapping capable unit to perform an autoroute on the pc and then download both the maps and the resultant route to the unit for execution. Even units that do not support maps can use a downloaded route to guide the user to the destination. Third party programs such as Delorme Street Atlas can also autoroute on the pc and then download the resultant route to a Garmin receiver however only Mapsource can also download the exact map that was used to generate the route.

Getting the right Map

The GPS V comes with a copy of Mapsource and a set of maps called "City Select". These maps have been optimized for use on the small screen of the GPS V by limiting the length of some of the instructions so that they will fit on the screen. There are "City Select" maps available for the USA and for Europe. "City Select" maps are made and licensed from NavTech which is a major map supplier that also supplies maps for most of the gps systems sold as preinstalled in automobiles. As part of the purchase price the user in entitled to unlock one region from the cdrom. The rest of the cdrom can be unlocked for an extra fee. For Europe the City Select data includes not only major cities street level detail but also detail for the surrounding countryside and smaller towns. Unfortunately, at this time, this is not true for the USA where only major towns are covered with street level detail. A new release of full coverage for the USA has been announced.

In order for the GPS V to use a map for autorouting it must first be downloaded to the unit. There is 19Meg of memory available for the maps so the user may have to be choosy about which ones are loaded at any one point in time. Of course a different set can be downloaded as needed. Each download overwrites all of the previous maps so map loads are not incremental.

For the USA there there is a another choice for maps available from Garmin called "MetroGuide USA". These maps also have the extra information needed for autorouting and cover the full USA with street level detail. In addition there are no unlock codes so the purchase includes the full cdrom set. These maps are made by and licensed from ETAK, a division of Tele Atlas, which is a competitor to NavTech. They are good maps but some have reported that they are not quite as up to date as some of the "City Select" maps and do not have quite as much routing information. However, they can do a good job and provide the only available autorouting solution for many parts of the USA. It is possible to download a mix of "City Select" maps and MetroGuide maps so long as it is done in the same session.

Garmin has also released a set of maps for Europe called "MetroGuide Europe". This can be a bit confusing because these maps are from NavTech and are the same maps used in "City Select." They do not support autorouting on the GPS V but do support autorouting on the pc thus the results can be downloaded to he GPS V. They do not require regional unlock codes.

The GPS V can also use its basemap for autorouting thus it is possible to have a mix of maps that cover a single route. The GPS will automatically use the 'best' map(s) it has for the area that it is trying to route. It will choose "City Select" first, "MetroGuide USA" second, and finally the basemap. There is usually no need to have detailed maps of the entire journey in the unit. You might have loaded detailed maps for the start of the journey and the end of the journey and use the basemap for the road coverage in between.

It is possible to load any of the other maps available from Garmin into the GPS V as well, however they will not be used for autorouting. Of course the GPS V also supports manual routing, which is covered in the chapter on routes. Manual routing is used when the destination or route is off road. It may also be the best solution for long over the road routes between cities.

Performing an autoroute

Route creation begins by visiting the main menu (press the menu key twice) and then highlighting and selecting the route command. Select the "New" button to begin a new route. The following steps are used to create the route:

  1. Select the type of route, "automatic" from the menu. (Creating a manual route ("offroad") is covered in the route chapter.)
  2. Select the desired destination by category from the Find menu. Any of the choices is available for autorouting. However some of the choices may have a final leg that is off street since the location may not be on a road.
  3. Once the choice is on the screen select the "GOTO" entry and press enter.
  4. A menu will appear that offers "Faster Time", "Shorter Distance", or "offroad". Select one of the first two for your autoroute. If the final destination is off road and you have not selected offroad the autoroute command will compute a route that takes you to the closest road perpendicular to the desired destination.

A small box will appear in the corner showing that the gps is computing a route. Once the route is completed the unit will automatically begin navigating the route it just computed. A new turn by turn current route page will appear in the page rotation for the gps.

It is also possible and perhaps simpler to begin a route from the find menu. Press the find button and proceed from step 2 above.

If the route is too complicated you may see a message saying "Too many vias for Road Navigation". This means that the route requires too many turns for the unit for calculate (more than 50). To recover from this error either compute the route manually (see below on using manual and automatic routes together) or choose an intermediate destination and retry the calculation.

Saving the route

It is not necessary to save the route in order to use it. However if you want to save the route for future use it can be saved by going to the active current route page and selecting "save route" from the local menu. It will be named automatically and a small car icon will show to the left of the name on the route page to indicate that this is an automatically created route (manually created routes show a hiker).

Note that saved routes can be used in the future but cannot be reversed like a manual route can. This is because the turn by turn instructions are very dependent on lanes, freeway exits, one way streets, etc. It is possible to save two routes, one in each direction. To use a saved route, visit the route page from the main menu, select the route you want, and answer the popup window with "Yes" that you do want to navigate this route.

The route page is also the place that allows you to rename the route or delete it. Select the route and then press the menu button to see a list of options. Select the one you wish.

Creating an automatic route from a different starting point

Generally the gps V will always expect that you want to create a route from your current location. However, for planning purposes, you may wish to generate a few routes ahead of time. To do this you can use the simulation mode on the gps to move your current location to the desired starting point. This is most easily done by going to the satellite status screen, select Use Indoors (simulation mode), and selecting new location from the local menu. Once you have selected the desired starting point then perform a normal automatic route calculation, and then switch to the current route screen and save your new route.

Using an Autoroute

You will generally use the map page and perhaps the active route page when running a route. The map page shows different information when navigating than it does when just viewing the map while using the gps for position. Both settings are customizable from the map page local menu. In addition separate settings can be obtained by switching the screen from landscape to portrait mode (press and hold the page key). The defaults setting, however, are likely to be the ones you want.

When you customize the navigation menu you can select the 4 entries as shown or only 3 entries with the upper one replaced with a double sized box that has a direction arrow in it. The large arrow provides visual direction and turn information including the approximate amount to expect from an upcoming turn similar to the arrows shown on the active route page. Even with the 4 box choice a smaller straight arrow is available.

The map page will show guidance text at the top of the screen (may be turned off if desired from the local menu) which provides essential information for the next turn. When not navigating this information shows the name of the next street or next freeway exit. Sometimes this is useful even when navigating. To see this data go to the active route page and select suspend routing (Do not select stop routing on the map page.) and the next road data will appear at the top of the map page. Select resume navigation to return to turn by turn instructions.

The active route page shows the information on the next turn and the following 3 turns. It is updated dynamically as you travel the route. You can choose whether to show the projected arrival times or the times to go for each of these turns from a choice on the local menu. These times are computed using a proprietary algorithm but seems to be based mostly on the speedlimits assigned to the various roads. It will not recompute them if you slow down for a turn or stop for a traffic light except to extend them for the amount of the stop.

Pressing enter while on this page will bring up a detailed turn map for the next active turn or if you select one of the other turns it will bring up the detailed active turn map for that turn. These maps always assume track up to that they can be interpreted as left or right turns. These are the same maps that will popup automatically as you approach each turn (if enabled) no matter what page you are currently viewing.

The local menu is also the place to temporarily suspend a route, resume the active route, recalculate the route, or force a detour calculation. Selecting a detour brings up screen that allows you to mark the current road as impassable for a specified distance. The GPS will then calculate an alternate route that does not use this road. (This may require a U-turn.)

As you follow your route you will find that the gps V will give you ample warning for each upcoming turn. It provides a beep early on to alert you to an upcoming turn and a second beep when you are almost on top of the turn. The first beep is a variable time based on your current speed (a feature also of the emap product). At night, if the backlight display has timed out, the backlight will turn on to alert you to the turn. You can set the maps to change scale as you near the turn but generally this is not as necessary as it might be on other units since the detailed pop up screen will provide a map for the turn itself.

If you get off route the gps V will detect this condition and provide a message. It will say "Off Route" or if you have automatic recalculation enabled it will say "Off Route - recalculating" and will provide a new solution when the calculation is complete. If you continue off route without recalculating you will need to use the map of the highlighted route plus the arrow, if configured, to find your way back.

Recalculations

There are a number of times when you may wish to perform a recalculation of the route. For example, perhaps you got off route and need to find your way back, perhaps the road ahead is blocked and you need to detour around the area, and finally the original route may have been done for over the road use and you now need a more accurate detailed final route. Each time the unit performs a recalculation it basically starts over from your current location and computes the full solution again. A detour is a special case in that you can specify not to use the current road for a certain distance. It does not just calculate a route back to the original route since there may be a better way from where you are and you are often closer to the destination when the recalculation is requested which may result in more detailed information. This is particularly true when the original route was calculated using a setting less that the "best route".

Setup Preferences

There are several setup items that can be used to enhance and control the autorouting capability.

Map Page Setup

On the map page you will want to select the lock to road feature. You will also need to enable the maps your wish to use using the Mapsource Info menu item. It is possible that the routing and the display are using different maps. For example if you routed an area on the basemap but have the topo maps enabled you might be looking at an area on the topo map and using the basemap for autorouting. This can cause discrepancies between what you are seeing and what the guidance being offered by the autorouter.

Main Menu Setup

The main menu setup choice provides two entries for automatic routing use, guidance and routing.

Guidance setup determines how the gps behaves when using the active route. There are two entries on the page.

Routing setup controls the way the routing works. There are several setting on this page.

Using Manual Routes and Autoroutes Together

There are lots of reasons you may need or want to use a manual route in the gps V. For example you used a 3rd party program to calculate the route for your vacation and wish to download this into the gps v. Perhaps you have a scenic route in mind and would like to dictate the intermediate points along the way. Maybe someone sent you specific instructions to find their house which may be better than the route the unit might compute. I have seen cases where there is a locked gate across the road that the map database didn't know about, for example. You may have travel to a location and kicked off the trackback feature to return using the saved tracklog. And finally, the trip you are planning is too complicated for the router or you don't have the correct maps downloaded into the unit at the time you setup the original plans. This can easily happen on a vacation where you intend to load the next days maps into the unit each evening.

However, it can happen that while traveling using a manual route you encounter a condition where you need an automatic route. For example you miss a turn and need a calculation to get your back on route, or perhaps there is a detour that you didn't know about. While the route is still active press and hold the find key. This will bring up the active route screen and you can select the desired destination. When the waypoint screen appears select the goto button. This will cause a calculation of a route to that point as a destination which you can then follow to get back on track. Note that after the automatic calculation you will need to manually reenable the original route if you still need it.

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