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E-Hiking
How to record your trip electronically and share it online
THE TOOLS
You'll need digital maps on your computer and a GPS receiver in addition to the traditional trip-planning tools.
Digital maps can be installed locally on your own computer, or downloaded as needed from the Internet. Local
maps are usually faster to use and cheaper per unit area, and don't require an Internet connection. Examples of
digital maps include Garmin's Topo USA 100K and 24K series, which are designed specifically for Garmin mapping GPS
units, and Delorme's Topo USA, which offers low-cost coverage of the entire U.S. and work well with DeLorme GPS
units. National Geographic Topo! State Series has complete USGS topo coverage of an entire state or region and work
with nearly all GPS receivers. Instead of installing maps on your computer, online maps such as Expert GPS and
National Geographic Topo! Explorer allow you to download standard USGS topo maps. Google Earth features free
satellite photo coverage of most of the planet, and is a useful trip planning and sharing tool.
To navigate and record your route, you'll need a high-end trail-type GPS receiver that has mapping capability. Such
units are available from Garmin, Magellan, DeLorme, and others. Check their Web sites to compare specs. Mapping GPS
units have a preloaded base map, and allow you to upload more detailed maps. Other key features to look for in a GPS
are a high sensitivity receiver, AA or AAA batteries, long battery life, waterproofness, USB computer interface,
magnetic compass, barometric altimeter, sun and moon data, and tide tables (useful to a sea kayaker).
A word of warning: Don't depend solely on your GPS for navigation. Electronics can fail at any time, the batteries
can die, or the unit can be lost. Always carry paper maps and a standard liquid-filled compass as a backup. And learn
how to use your GPS and digital maps at home before using them on a trip.
Before planning a trip, you'll need to do some setup. Make sure the GPS receiver is set to the same map datum as your
maps. The datum is the ground reference system used to create accurate maps - if you set the wrong datum in your GPS,
the reported position can be off by hundreds of feet or even several miles. Maps are normally printed and displayed
with true north, and you'll want your GPS set the same way. A conventional compass points to magnetic north, which
varies from place to place on the Earth, and can be 10 or 20 degrees different from true north. This difference is
called declination. I prefer a compass that has a declination offset adjustment, so I can set it to read true north
for the area of my trip. You'll also need to set the GPS to display the same coordinates used by your electronic map.
Coordinates are a pair of numbers used to describe your position on the Earth. Although there are many coordinate
systems in use, the two you'll encounter most are latitude and longitude (lat/long), and Universal Transverse
Mercator (UTM). Lat/long is the most common and is found on every map that is accurate enough for navigation, but
it's a pain to plot by hand on a paper map. UTM is a newer system based on 1,000 meter squares, and is much easier to
use in the field. Most electronic maps can be set to use UTM, and since GPS receivers use UTM internally (no matter
what coordinate systems is on the display), I recommend UTM.
It is important to initialize and calibrate your GPS before using it in the field. You should do this at home and
again at the trailhead. To initialize, take the GPS outside where it has a clear view of the sky, and turn it on.
After about a minute, it should lock onto the GPS satellites and display your position. The satellite status page
shows the number of satellites received by the GPS and their signal strength. GPS needs at least four satellites for
an accurate position.
If your GPS unit has a magnetic compass and barometric altimeter, you'll need to calibrate them. The compass is
generally calibrated by turning in a couple of complete circles, but check your receiver's manual. The electronic
altimeter uses barometric pressure, which varies with the weather and with elevation. You must set the altimeter to
either a known elevation or the local barometric pressure. At home, you can get the pressure from the nearest
airport. In the field, you can plot your GPS position on a topo map and read the elevation from the map. The
altimeter must be calibrated several times per day to follow barometric pressure changes, otherwise it can be off by
hundreds of feet. If properly calibrated, barometric altitude is much more accurate than GPS altitude.
TRIP PLANNING
To explain the use of e-hiking tools for trip planning, I'll use the Aubineau-Bear Jaw Loop, a hike in northern
Arizona. This gorgeous summer hike on the north slopes of the San Francisco Peaks connects the Aubineau and Bear Jaw
trails for a fine 9.8-mile loop.
I planned the trip myself using National Geographic Topo! Arizona, but you can download trips recorded by others,
either as files produced by programs such as National Geographic Topo! (the TPO files are small and easily emailed),
or from the Internet using sites such as National Geographic Topo! Explorer, EveryTrail.com or Google Earth. The
standard GPS file format is GPX, but not all programs use it. A free program, GPSBabel, converts between most formats
- just Google for it.
Using digital maps, trip planning consists of drawing freehand routes, plotting GPS waypoints, and creating GPS
routes. But for finding the trail to hike or the route to paddle, you'll need personal knowledge of the route, that
of a reliable friend, or a guidebook.
For trail or cross-country hiking, snowshoeing, or skiing, start by using the route tool to draw a freehand route
along your trail or travel path - because these routes rarely travel along straight lines. For paddlers, where you
can often travel along straight lines, you can skip this step.
Then, start a new GPS route and place waypoints at all the key points along the route. This includes the trailhead,
boat launch, or starting point, trail junctions, islands, buoys, or other places where your course changes. You
should also mark points of interest such as springs, campsites, or other features you want to check out. Along a
trail or cross-country route, place as many waypoints as you need to follow the twists and turns of the route.
As you place waypoints by clicking on the map, you'll be asked to either name the waypoint, or accept the program's
default naming. I suggest you use descriptive names in abbreviation, such as ABTH (for Aubineau trailhead), BJJCT
(Bear Jaw Junction), and AVAL1 (avalanche path). You can put the longer descriptions in the remarks' field. You can
also name the route itself - in this case ABBJLOOP (Aubineau-Bear Jaw Loop).
Once you've plotted the route, you can display an elevation profile, which is very useful for trips in the mountains.
Then, you can print a map showing your planned route. When printing, it helps to use a standard scale, such as
1:24,000 or 1:62,500, used by USGS topo maps. Often, you'll have to print several maps to cover the entire route -
make sure they're all at the same scale. Maps can be customized with the desired coordinate system and can be printed
with the elevation profile, if desired.
Usually, you'll want to print on a color printer to show all the features on the topo map. Unless printed on
expensive waterproof paper, inkjet maps are easily wrecked by moisture. Keep them in plastic bags or map cases. Laser
printed maps are much more water resistant. Finally, you'll want to upload the GPS route and waypoints to your GPS
using the USB cable that came with your unit. I prefer to erase all existing routes, tracks, and waypoints in the GPS
first, so all the data is relevant to the planned trip.
RECORDING YOUR TRIP
On the trip, carry the GPS receiver so that it has a clear view of the sky and is accessible. This can be
accomplished by attaching a carrying case to the shoulder strap of your pack. Boaters can carry the unit in a clear
deck case.
At the trailhead or starting point, be sure to initialize the GPS and check the accuracy reading. Save a waypoint to
record your starting point, in case the planned trailhead waypoint is wrong, and as a backup. In fact, if you don't
do anything else with your GPS, record the trailhead location! When you save a waypoint (also called marking your
location) on the GPS receiver, it gives the waypoint a default name, such as 001, 002, etc. Although you can rename
waypoints on the GPS, it's tedious. I use the default waypoint names and make notes in a small notebook or on a voice
recorder. You'll also want to clear the track memory and make sure the GPS is set to record a tracklog, before
leaving the trailhead. A track is just a series of waypoints saved automatically by the GPS receiver as you travel.
Since you can't display the track log as waypoints, you should also save waypoints at key points as you go.
You may also want to reset the trip computer page on the GPS before you start out. This page displays the distance
and time that you traveled. For hiking and skiing trips, use the distance accumulated by the GPS with caution. At
walking speeds, GPS distances aren't accurate, because GPS position fixes are used to calculate distance. Since
civilian GPS is accurate to about 15 meters (49 feet), at walking speeds the position fixes are too random for
accurate distance measurements along a trail.
NAVIGATING THE PLANNED ROUTE
Before you set off, switch to the route page on your GPS and activate the route. The compass screen shows the bearing
to the first waypoint along the route, and the map page shows the course line and waypoints.
As you travel, you should save waypoints at key points to supplement the track log. On a hike, mark trail junctions
and key landmarks, and any other points of interest. Remember to take notes so you'll know the purpose of each
waypoint. You can also note the approximate location of the waypoints on your paper map.
On a trail, you can't normally hike directly to each waypoint along the route, but the GPS lets you know whether
you're heading in the general direction, and your estimated time of arrival (ETA). As you reach each waypoint, the
GPS automatically starts navigating to the next waypoint. A route page shows you the ETA at all the upcoming
waypoints, including the last one at the end of the hike. On hikes, the ETA is lower than your actual time, because
the GPS assumes you'll hike in a straight line.
On water, when you can paddle directly to each waypoint, you'll use the course indicator on the compass page to stay
on your planned course. The GPS make it easy to correct for wind and current drift. The ETA shown is very accurate,
if you maintain a consistent speed.
Cross-country hiking is usually anything but direct, as you detour around obstacles while maintaining your course
toward the next waypoint. The map page makes this easy - it graphically shows the original course and which way to
turn to get to it.
SHARING YOUR TRIP
When you get home after your trip, download the GPS data to your computer, where you can then add notes, symbols,
graphics, photos and videos to the GPS data. The older programs, such as National Geographic Topo!, DeLorme Topo USA,
and Expert GPS create files that you can email to your friends or post on a website. The recipient will need to have
the same program to open the file. Otherwise, a program like GPS Babel will convert the file to other formats but
multimedia files will need to be emailed separately.
Sharing on the Web keeps the GPS and multimedia files together, so you can literally share the trip - a true
electronic journal. National Geographic Topo! Explorer has the same tools as NG's Topo! State Series, only online via
a free program that you download. GoogleEarth is another excellent way to share waypoints and photos on
satellite images of your trip. There are many other trip-sharing tools on the Web. My favorite is everytrail.com,
where you can see the Aubineau-Bear Jaw Loop at everytrail.com/view_trip.php?trip_id=418873.
Bruce Grubbs is an active outdoor writer and photographer with 20 books in print. His "day job" is flying air charters.
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Tuesday, February 02, 2010
at 3:07:30 PM
Suggest removal
Michael says:
So now we can plan, execute, and recall our outdoor travels without ever leaving our computers. Oh boy.