Not Just For the Misdirected Anymore - GPS Buyer's Guide and Glossary
Author: Rafe Nielsen and Wes Wiedmaier
With rocket-science terminology and ambiguous acronyms, potential GPS buyers may find it’s easier to find their way out of the mountains without a GPS than it is to purchase one. Although there are some highly technical terms, choosing the right one for you can be fairly simple.
An eerie feeling came over me when I realized I had no idea where I was. In the thick timber, every tree looked the same. I thought the trail was to my left, it wasn’t. My best guess led me to a beaver pond that I didn’t know existed. A reversed track led me to a new meadow. The sun started to go down over a ridge I had never seen. As the dark settled over me, I began to mentally prepare for a long night away from camp. In a final effort to find something familiar, I stumbled onto an old logging road. Knowing the road would eventually lead me to someplace warmer than a tree stump, I followed it until I was in country I recognized. Several miles later, my tired legs found their way to camp where a hot fire and a warm sleeping bag awaited me. From that elk hunt on, I vowed I would never hunt again without a GPS unit, even in areas where I was familiar.
I had that same eerie feeling when I went to buy my first GPS unit. I was as lost in that store as I was on that elk hunt. Between the rocket-science terminology, ambiguous acronyms and broad range of products, potential GPS buyers can start believing it’s easier to find their way out of the mountains without a GPS than it is to purchase one. Although there are some highly technical terms and a confusing array of products and prices, choosing the right one for you can be fairly simple.
The first thing you need to do is determine what you will be using your GPS unit for. GPS units are highly specialized with features unique to each one. As the number of features increase on a GPS unit, so does the price range. From the well-seasoned navigator to the novice, GPS units can offer a variety of functions to fit specific needs. The adventurous, always on the road traveler will appreciate the highly detailed mapping functions of upper-end models, while lower-end models will serve the needs of those needing only to find their way from point A to point B. Knowing what features are available and what they do will help you decide which ones you need in your GPS unit.
Waypoints are the heart and soul of the GPS system. A waypoint is simply any place that you want to mark on your GPS, such as your home, a hunting camp, a downed animal, stand location or a favorite fishing spot on a lake. Once a waypoint has been marked, your GPS will let you know how far away you are and in which direction to go to return to it, no matter where you are. Let’s say you just shot a big bull elk in dense timber and need help getting him out. Simply mark that spot as a waypoint and return to camp for help. You can then use your GPS to navigate you and your partners right back to where your elk is without a problem. It is important to mark a waypoint such as a car, camp or dock, before you wander off so you have a place to navigate back to. GPS units vary with the number of waypoints they offer, and can range from 1,000 all the way down to simple models that store one for simplicity. These models are great for finding anything from a treestand to your car in a parking lot.
A route is a series of waypoints on a single course
of travel. This allows you to navigate through a series of waypoints either forward or in reverse order. Routes can be used when mountains, lakes or canyons prevent you from traveling in a straight line. By entering in coordinates as waypoints you can create a route that will lead you around difficult or impossible terrain. Waypoints can also be marked as you travel so you can return to each of them on your way back, again avoiding rugged terrain. Outlining a route allows you to stay on a course leading you safely to each waypoint. The number of routes available can also vary from one to 50.
While traveling, GPS units can record the path you take in a track log. Every twist and turn you take along a trail or road will be stored, leaving an "electronic bread-crumb trail." This allows you to see exactly where you have been during your travels. A track log can be activated into a reverse route and will automatically set enough waypoints along the track log to guide you back to your original starting point. This track log can be saved as a route so you can use it whenever you need to.
The accuracy of GPS units will vary according to outside conditions. Tall buildings, dense foliage and other obstacles can affect the accuracy of any GPS unit. Newer receiver chips and advanced technology, like satellite prediction, has greatly improved accuracy and updating, even in heavy cover or rugged terrain. Under most conditions, GPS units will be accurate to within 50 feet or closer. Greater accuracy can be obtained through either a Differential GPS or a WAAS system.
Differential GPS (or DGPS) was originally setup by the U.S. Coast Guard for navigation on the seas. DGPS works by having a GPS receiver and a transmitter placed in a known location. Because this site is stationary, it knows its exact location and can correct any errors from the satellite. These corrections can then be transmitted to your DGPS receiver and then to your GPS unit. DGPS accuracy is approximately within 5 meters and works well for coastlines and most of the inland U.S. The only catch is you need to have a DGPS receiver along with your GPS unit.
WAAS (or Wide Area Augmentation System) was developed by the Federal Aviation Administration for pilots traveling in adverse weather conditions. WAAS operates from 25 networked ground reference stations. Much like the DGPS, these reference stations receive signals from the satellites and correct any errors. But instead of transmitting these corrections to a separate DGPS receiver, the corrections are sent back to the satellites, which can then transmit the correct information directly to your GPS unit. WAAS can greatly increase accuracy down to 3 meters. Most GPS models for use in North America now come standard with WAAS capabilities.
GPS units come with a variety of mapping features. Knowing what you will be using your GPS for will help you determine which mapping functions you will need. If your only concern is to find your way back to camp you won’t need a mapping system that shows you where each golf course is located along the interstate. The three basic types of mapping systems are nonmapping units, mapping units and basemap units.
As the name indicates, nonmapping units do not utilize any type of mapping system. The plotter screen shows waypoints, routes or track logs and your position
relative to them, as well as how to navigate to these points. Some higher-end nonmapping systems will show locations of major cities on a city point database. Nonmapping units do not show rivers, lakes, roads, interstates or physical landscapes. These units are ideal for first time users trying to learn how to operate a GPS. They are also excellent for someone who is familiar with an area and needs only to mark waypoints for future reference, such as where camp is located, a secret fishing spot or a downed animal.
The use of a mapping unit provides the most detail of any system. Mapping units typically operate by loading map data from data cards or CD-ROMs off your personal computer. Depending on the software you buy, downloadable map data can include such detail as residential streets, restaurants, gas stations, tourist attractions, boat ramps, topographic detail and even off-road trails, as well as rivers, lakes and major road systems. With a highly detailed map downloaded on a GPS, a traveler can navigate directly to a street address, the nearest golf course or a favorite restaurant. Newer mapping systems include satellite imagery and 3-D imaging that can pan down to a first-person view. A mapping unit is perfect for people who are traveling in unfamiliar country and could use all the information contained in a specific database. For hunters, fishermen and hikers, a mapping system can give them realistic details of unfamiliar territory, along with rivers and lakes to navigate them through unknown country.
A variety of CD-ROMs with downloadable maps are available for mapping GPS units. Software can be bought for specific regions and with specific information, such as road systems and tourist attractions for travelers, or topographical details with rivers and lakes for outdoor enthusiasts. The software you buy must be compatible with your GPS unit, and most GPS manufacturers also produce mapping software for their units. The amount of downloadable memory on your GPS will also dictate the detail and amount of maps you can download on your GPS. Some units will allow you to download directly onto your internal memory, while others require data cartridges.
Basemaps are built-in maps on a GPS unit. A typical basemap will show interstates, state highways, major metro thoroughfares, cities, airports, lakes, rivers and exit information such as restaurants, hotels and gas stations. Basemaps are great for road travelers who need to know distances and locations of basic places. Outdoor enthusiasts can use this information to give them reference points to local cities and distances to major lakes and rivers. Some models come pre-loaded with advanced maps ready to use right out of the box.
All mapping systems allow you to utilize the waypoint, route and track log features on your GPS unit. The use of these features, along with a mapping system greatly enhance your navigational ability and allow you to easily arrive at your desired destination.
Download memory is applicable to mapping units and will determine how much map information can be installed on your GPS. A low available memory such as 1MB will limit you to how much detail your maps can contain and the number of maps you can download. 8MB memory is common, but newer units offer 24MB, allowing you to download a number of detailed maps without having to replace existing ones. It is a good idea to check how much memory your GPS contains and what is compatible with your unit before buying any software.
The compass feature on many GPS units only offer a heading while it is moving. Once a GPS unit becomes stationary, the compass fails to operate accurately. To compensate for this, some manufacturers have included an electronic compass, which operates while it is stationary. Having an electronic compass eliminates the need to carry along a separate compass for navigation and will provide immediate, accurate directions. Most units must be quickly calibrated the first time they are used or whenever new batteries are used.
The size of a display screen will depend on the size of the GPS unit. Smaller units will of course have smaller screens, but that doesn’t mean they won’t be clear and easy to read. The number of pixels will determine how clear your screen images will be. Pixels will vary from 64 x 128 to 160 x 288 or more depending on the model and price. Most models will have backlighting so you can use your GPS unit during the day or at night. Color screens are becoming more prevalent, especially on models featuring satellite perspectives, 3-D imagery and built-in digital cameras. These systems create the most realistic mapping available.
Just like it has revolutionized the cell-phone industry, touch-screen technology promises to do the same for GPS models. Higher-end models have combined the intuitiveness of touch controls with full color screens. Most midrange GPS units have button or toggle controls on the front of the unit above or below the display screen. This allows you to have a full view of both the display screen and the control buttons. The more intuitive the controls on a GPS, the more quickly you’ll be able to navigate through a menu, scroll across the screen, and set waypoints and routes.
The functions on a trip computer will vary greatly based on the model and design. For the most part, a trip computer will provide maximum and average speeds of travel, and trip timers and distances. These features will show you how far and how long it will take you to make it to the next city, hotel, hunting camp or any other waypoint you have set as a destination.
This measuring tool uses coordinates to accurately determine the size of irregular-shaped areas. The feature proves indispensable for tasks like calculating how much seed or fertilizer is needed for food-plot coverage.
Ever take a picture and wish you knew exactly where it was taken? Now you can capture a picture on a GPS with a built-in digital camera and the exact coordinates will be embedded on that image using geotags. If you want to return to the same spot 20 years later, the geotagged picture will take you right there. Once the image is saved on your GPS, it can be seamlessly transferred to compatible mapping software.
Two-way radio/GPS combos:
These units combine the navigation of a GPS with the communication of a two-way radio. The two-in-one convenience frees up space in your pack. Peer-to-peer positioning “beams” your location to another user within a two-mile range. This shows the receiving party the exact distance and bearing from your position to theirs. You’re probably thinking – what a great idea for hunting. The catch is that these devices are not legal for hunting in all states. Be sure to check your state’s regulations.
Like their automotive counterparts, some handheld GPS models are turn-by-turn capable with the purchase of additional software. Consider one of these units if you want a GPS with the versatility to navigate in the field and on the road.
Built-in data ports accept SD cards and other similar storage devices, allowing you to play MP3s or check game-camera pictures in the field.
Best described as a high-tech game of hide and seek. Participants use their GPS to find hidden containers called geocaches, usually a waterproof container with an item or items and a logbook inside. The items are usually small and are not high in monetary value, but may be of personal value to the finder. A geocacher hides the items and records the coordinates. Other geocachers plug these coordinates into a GPS to find the geocache and then record it in the logbook and online. Most GPS units can be used for geocaching.
Wireless data sharing:
Similar to sending texts or pictures between cell phones, GPS models with wireless sharing allow you to transmit saved data, such as waypoints, to another similarly equipped unit within range.
Internal barometric altimeters more accurately determine altitude readings. This feature is beneficial when used in conjunction with topo maps. Altimeters can also be used to determine weather trends.
A variety of accessories are available for specific models. Many models come bundled with all the accessories you need to get started, saving you money and simplifying the purchase.
Other trip computers will include a variety of functions to assist you during your travels. Hunting and fishing calendars tell you when the best time to be afield is throughout the year. Sunrise and Sunset Schedules give you the correct times the sun will rise and set no matter were you are. This is a great function for hunters and fishermen who can use it to determine legal hunting and fishing hours. Altimeters can give you your elevation from sea level and will often include your rate of ascent or descent, along with your maximum and average elevation, a great feature for hikers and hunters who need to gauge their altitude. Barometric Sensors can quickly tell if you need to find a place to get out of the rain. For anybody who might encounter frequent rain and snowstorms, and understand how a barometer works, this feature can be worth its weight in gold while in the field.
Simple Use Tips
1. Learn how your GPS works.
Having a GPS in the field doesn’t help you unless you know how to operate it. Read the instruction manual all the way through several times before you ever take it out to use it. Learn which controls do what and become familiar with the terminology used.
Spend an afternoon or two in a local park setting waypoints, marking routes and following your track logs. Do the same thing around town in your car. Putting your GPS unit to work in a controlled environment will help you understand each feature. Being able to navigate in unfamiliar territory will be easier if you have practiced beforehand.
3. Mark waypoints throughout your trip.
Mark waypoints at camp, parked vehicles, trailheads and other important destinations. Take a few seconds to mark a waypoint whenever you make a significant change in direction on a trail or ATV road. Without waypoints, your GPS unit can’t navigate you back to where you want to be. Never leave your returning destination without marking it as a waypoint.
4. Check battery life.
A GPS unit with dead batteries in the field is as good as not having one at all. Find out how long your unit will operate on batteries and record how long you have used it. Always replace the batteries before you need to, ensuring you won’t be left without power when you really need it. It is also a good idea to always carry along an extra set of batteries, or two, in case of emergencies.
5. Protect your GPS from damage.
GPS units are rugged and durable, but they can become damaged and not work properly if undue wear occurs. Find a safe place in a backpack or pocket to carry it. Carrying cases are available for most models, and some can be hooked to a belt for easy access.
6. Don’t rely solely on a GPS.
GPS units are designed as navigational tools, not a sole life-saving device. The use of individual compasses and maps, along with your GPS, is recommended during travels. Above all, use common sense. GPS units can help you find your way in unfamiliar territory, but they can’t help if you are injured or your vehicle is stuck in some remote location. Just because you have a GPS, doesn’t mean you can go anywhere and do anything. Be smart and careful in all your travels, regardless of your navigational tools.
GPS units have become as common as cell phones in recent years. They come in all different sizes, shapes and colors. The design of civilian handheld GPS units have made them simple to use and easy to carry. Whether you are going on an extended vacation across the country or backpacking into unfamiliar territory, a GPS unit can be a great asset to have along the way.
A GPS can go from a fun toy to a necessity before you know it. It is important to know how to use one before you rely on it. Read and understand the user’s manual of any unit you buy and practice in your yard and around town to really get to know how it works. Knowing how to use it will greatly enhance your ability to find your way back to camp when that eerie lost feeling comes over you.
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