Navigation / Map settings

when you think about it - pedestrians or bicycles do not have to worry about one way streets - the fastest route cannot be a highway - they can use unpaved roads such as in a park.
Emergency vehicles can take a more straight line and u turns approach with the proper sirens and flashing.
Taxis - is a litte mystifying - possibly route to the location making sure you exit on the passenger side at the location and not have to run across the street.
You will see that there is a difference on Guidance only and guidance & status. It is subtle. Guidance only has less chatter. So for example at a turn it will say make a left only once and then will not talk until you make or miss the turn. Guidance and staus on - you will usually get two chats - one within .1 mile and another at 300 to 400 feet as you approach the turn. Go through a tunnel with guidance and status it will tell you about satellite reception - with guidance only it will put a warning mesasge on the screen - no talk.
Map outlines on/off - On - according to the manual will work if you have multiple maps on the unit - no effect if you don't have multiple maps

Since We are talking about differnces, I always wanted to know the major differences between the three settings and which one is most often used ("Track Up"; "North Up", and "3D") I know 3d is default..

Track Up has the vehicle pointed to the 12 o'clock position (the map will rotate around the vehicle).

North Up has North pointed to the 12 o'clock position (the vehicle rotates within the map).

3D has a track up view with the bottom having a narrow field of view and the top a wide field of view, giving the effect of 3D, it also appears to show terrain if you look in a city area where the roads are laid out in a grid fashion, you can see bends in the roads which show hills, and valleys.

Thanks for the info

Anyone know the difference between the waas setting and normal setting, and if there is preffered time to switch between the two?

For my c340, the specifications (at http://www.garmin.com/products/sp340/spec.html) show the "GPS accuracy" to be less than 15 meters (49 feet), but they show the "GPS (WAAS) accuracy" to be much better (less than 3 meters). I'm not sure why I would ever want to use the normal setting when WAAS is apparently much more accurate.

I've got one: On the C530, among the "Avoidances" you can choose to avoid, one of them is Traffic. I think this is completely separate from the optional FM traffic receiver. So what does this particular avoidance help you avoid? Does it know the particular roads that are likely to have traffic?

> Anyone know the difference between the waas
> setting and normal setting, and if there is
> preffered time to switch between the two?

With WAAS turned on, additional information is recieved and used in the calculations. There are ground stations located at fixed and known locations which monitor the sattelite positions and correct mathematically whatever amount of inacuracy is present due to atmospheric conditions or other things that would affect the accuracy.

If a WAAS sattelite is available, it will show up on your GPS info screen with a number higher than 33.

The preferred time to turn WAAS off is anytime you are running on batteries and want to use less power for reception and processing of additional data. This is not an issue for in-car GPS, but for handhelds can make a lot of difference in battery life.

WAAS gets that increased accuracy by constantly checking with more satellites, I understand ... which is also the reason for the battery drain.

I believe the avoidance for Traffic is dependent on the FM traffic receiver. If you don't have it, it doesn't work.

mkahn, You're probably right about that. It seems strange to me, however, that there are two locations in the menu that deal with traffic. It has its own menu option under the "wrench" button, and it is also included in the list of optional avoidances. Do people who use the FM traffic receiver have to turn it on in both menus? Seems inefficient.

Pg 18-19 of manual

" Avoidances--select the road types you want to avoid on your routes. The c530 uses these road types only if alternative routes take you too far out of your way or if no other roads are available.
If you have an FM Traffic Receiver, you can also avoid traffic incidents."

WAAS stands for "Wide Area Augmentation System". It is primarily used for aviation. There are some accuracy errors within the satellite systems. In areas where aircraft routinely execute GPS instrument approaches thru the clouds, a local area transmitter broadcasts additional (augments)information to the GPS receiver in the aircraft to increase the accuracy. This allows the aircraft to execute an instrument approach to lower minima than would otherwise be allowed. In my opinion, WAAS enabled on a car GPS might not show any noticable improvement in navigation. I don't know how far the local area transmitter broadcasts can be received but since it is an FM signal, I would imagine it is line of sight. The aircraft would have a better chance of receiving it.

The WAAS signal is transmitted from the Ground Stations to specific satelites from which the WAAS enabled GPS obtains the data.
From Garmin site:
WAAS consists of approximately 25 ground reference stations positioned across the United States that monitor GPS satellite data. Two master stations, located on either coast, collect data from the reference stations and create a GPS correction message. This correction accounts for GPS satellite orbit and clock drift plus signal delays caused by the atmosphere and ionosphere. The corrected differential message is then broadcast through one of two geostationary satellites, or satellites with a fixed position over the equator. The information is compatible with the basic GPS signal structure, which means any WAAS-enabled GPS receiver can read the signal.

When having the unit choose a route with the traffic avoidance set to on, it will route you around any incidents that are enroute as it calculates. It will also automatically route you around if an incident occurs after the route is calculated.