I took a look at some of the online offers for free GPS software and found, like many "free" offers there were often limits and provisos involved. Often the freeware is a scaled--down version of purchasable products. Sometimes the free product has restricted functionality with features disabled, other products are trial--based and are disabled after a certain time (hours or days or use).

An example of limited free GPS software can be found at GPS Utility. The downloadable freeware is limited 100 waypoints and 500 track points. (There are 65,000 of each in the registered version of their program.) The free program gives you a good opportunity to try before you buy, and this is the benefit of most free programs.

There are online sites that list various free GPS software and describe how to use the programs after you download them. Often individuals who have used the programs themselves develop the sites. These are great because they give you an unbiased interpretation of the benefits and disadvantages of the programs before you use them.

Using free GPS software you can download programs that allow you to retrieve and display aerial photos, topographical maps, USGS landmarks. There are programs available that allow you import scanned images and add latitude and longitude points and other data.

Free GPS software downloads are available for PDA units that are capable of communication with GPS receivers. With these downloads you can have a useful navigation assistant, location database manager, and GPS data converter.

Programs to manage GPS waypoint and route files are available for both PC and Mac users. The waypoints and route files can be saved or converted to various formats used by other mapping programs.

If you need to transfer information to and from your GPS receiver and your home computer or laptop there are several free programs that allow you to do so. There are also programs that allow Garmin GPS receivers to "talk" to one another.

Many of the programs listed here are directed at the hiking/trekker community, but there are also free programs available for auto GPS systems and marine navigational systems. I found a couple of marine navigation programs that allow you to download nautical charts and plotters.

There are free GPS software programs that allow you to download street maps that might not be included in your auto--navigation system. If you intend downloading in--vehicle software, make sure that it has audio capacity, an essential safety factor for motorists. One such program offers data for several countries with voice guidance in twelve languages.

Free GPS software is also available for downloading to your cell phone. This is mostly tracking software and can be phone specific. You might want to check with your carrier before downloading anything to your cell phone to make sure that it does not incur extra charges.

As satellites are constantly moving, it is helpful to know the optimal time for data collection in your area. There is free GPS software that includes an almanac to let you know the availability of satellites at any given time.

Some of the free GPS software is brand specific. Programs designed for a Garmin receiver may not work for a Magellan, so check out the specifications carefully, especially if you intend purchasing a registered version after your trial period. Other software works with most brands.

Anne King is a sports and recreation writer in Boise, Idaho. For , visit Maps GPS Info.com which also provides practical information on GPS and maps that everyone can use. The website includes product reviews and a maps/GPS glossary.