A guide to buying GPS

Questions that you may want to ask.

Does it have the specs you need? Don't go overboard in weighing this. Most gps receivers have very similar specifications.

Can you easily find the data you need?
Do you have to change pages more often than you like?

Does the data have all of the formats you are interested in (grid systems, datums). If you want it to work with paper maps then learn about this before buying a unit.

How's the configurability, customization?

If you want a computer interface then does it support one?Can you get the programs you want to work the gps?

How is the screen display? Is the text easy to read?

Do you need an external antenna? Most of the time you don't but you need to evaluate this for yourself.

Do you want or need internal maps? Do you need to update them or provide more detail?

Is waterproof important?

User interface ok?

How's the battery life?

Available accessories, mounts, cases?

If you need built-in maps then how accurate are they? No current maps databases are as accurate as you probably thought they were.

Can the unit be upgraded? In this high tech market firmware upgrades are important.

Do I need dpgs? - an optional hardware unit that provides increased accuracy.

Do I need WAAS? WAAS can provide corrections similar to a beacon receiver and uses the same antenna as your gps receiver.

To get answers to these questions you can ask the salesman, but you may not be able to trust the answer unless you get one that understands gps receivers. A better route is to go to the manufacturer's web site and look up the data. They often have manuals available on-line so you can download and read about the unit you are considering. If you have friends with gps receivers that talk to them but learn a little first so you can speak the same language. Many gps users claim that the unit they decided on is the best. This may be true, but filter out the reasons and make sure that it is the best for what you need.

There are also some questions that you don't really need to ask:

Does it work outside the US? All receivers work anywhere in the world except units that only work with a laptop using a map display. Some of these won't work outside the US only because they need a map and may not provide any non US maps. This is another good reason to select a standalone unit.