Thinking about GPS? Some things to consider.
- Size matters
- Map detail is your friend
Background:
GPS technology is becoming more advanced and more affordable than ever. The first GPS units simply provided a digital readout with latitude and longitude information. Nice, but if you do not have a map or you have insufficient maps skills, you’re still lost. The next generation of GPS units provided monochrome moving background maps which offered the ability to better determine your location without much in the way of mapping skills. Today we have access to affordable handheld GPS units with vibrant color displays that will display the same level of detail as the best paper maps ever produced. (Generally the topo map software packages are scanned and georeferenced copies of 1:24K, 1:100K and 1:250K USGS topo maps—just what you want for high level map detail.)
Screen size is everything:
Take your newspaper-sized map and cut out a 1.5-inch by 1.5-inch section. Is this how you want to look at your maps? The more screen real estate you have the easier it will be to determine where you are and where you’re going. If your destination is 6 miles away, you won’t be able to see your current position and your destination on the same tiny screen without being zoomed out so far that you loose all map detail. This is where the laptop/tablet PC comes in. If you have room for one these in your truck, this might be the way to go. You can purchase a lower-end laptop for around $600, which is only about $100 more than you might pay for a handheld GPS or PDA GPS, and you have all the capability of a laptop and a 12-inch to 15-inch screen for viewing maps. Serial, USB or bluetooth GPS units provide the positional data to the laptop. Downside? It’s going to take a lot of space inside the truck, the hard drive’s moving parts may experience a reduced lifespan, too large to take hiking.
Laptop capability in a small package:
If you do not have room for a laptop, a personal data assistant (PDA) (also called a pocket PC) with a wireless bluetooth GPS receiver may be the next best thing. As of this April 2007 writing, most of the PDAs available from Dell and HP are around $299 to $500 and have 512 to 624 MHz processors, SD cards for 4+ gigabytes of storage (no moving parts, unlike a computer hard drive), and 3.5 to 4” screens. Many of the mapping software packages are available for Microsoft Windows Mobile-driven PDAs, which means you have a wide range of mapping products to choose from. The software packages I have tested come with a desktop version that allows you to do route planning on the PC, then an “export map and waypoints” option allows you to view the same map and route on your PDA. Most PDAs will ship from the factory with many of the utilities you will find on your desktop PC—calendar and address book functions, calculators, slimmed-down versions of popular word processing and spreadsheet applications and built-in wireless internet with an internet browser.
The advantages of the PDA over the laptop include cost, portability, saves room inside the truck and no moving parts to succumb to vibration. The four to eight buttons on the PDA units can be customized to perform certain tasks (like zoom in/out, pan, etc.) without ever touching the screen or needing to use the stylus pen. Downside is the screens are much smaller and more difficult to view and there is no mouse and only an on-screen keyboard to enter information. Bluetooth keyboards and mice are available, but it seems more practical to do heavy trip planning on the home PC and transfer the data to the PDA.
Garmin makes their own PDAs called the iQue, which run Garmin’s own GPS software. You have to run Garmin maps with the software and the software will only work with Garmin’s own GPS receivers, some of which are built into the unit. If you like the Garmin software, you can run it on a Windows Mobile equipped PDA, but you cannot use a non-Garmin branded GPS unit and expect the software to work. If you like Garmin products, you might find this as a nice alternative over the standalone handheld receivers.
Recreational GPS receivers:
Next in line is the recreational grade handheld GPS unit—these are the DeLorme, Garmin, Magellan, and Lowrance names you are probably familiar with. These units are rugged, often waterproof and finally feature SD card slots like PDAs for map storage. No matter what type of unit you buy, I highly recommend buying a unit with SD card or compact flash storage. 64K of onboard memory won’t store much in the way of maps.
These handheld units typically feature dedicated buttons to control zoom in/out, pan, feature mark, etc. The GPS receiver is integrated so you do not have to worry about GPS wiring or a wireless Bluetooth connection. The downside here is screen size and map detail. The display size of the popular Garmin 60CSX is only 1.5 inches by 2.2 inches, which means the display can be difficult to see if the unit is mounted on the dashboard. The recreational grade units come with proprietary operating systems, which means if you buy a Garmin (or any of the brands named above), you are limited to using their software and maps. In my experience, unless you buy the extra detailed state series (often $99 per state), you’re not going to get much map detail for off-roading. In addition, the processing power of these units is quite low, which can result in map flash while panning or moving at higher speeds when high level map detail is loaded. You will also not have wireless internet access or any software applications other than for mapping purposes.
A recreational grade unit would be my first choice for backpacking, however I think there are better options for backcountry vehicle travel.
"StreetPilot-type"
Moving slightly out of the “handheld” category are the larger dashboard units such as the Garmin 276c/III/IV/V/VI, StreetPilot and Lowrance Baja series. These units offer similar features as the handhelds, only with a screen size comparable to a PDA or larger.
Changing technology:
The recent introduction of the Delorme PN20 may change the way handheld GPS units are marketed in the future. This unit allows a user to display not only topo maps but also aerial imagery. This type of imagery can also be used on the PDA GPS units and laptop computers with the appropriate software. Viewing your position on an aerial photograph is an extremely useful tool for field navigation. The Delorme also has the ability to import custom maps. With the depth of geographical information being made available on the internet, Garmin, Magellan and Lowrance are going to lose marketshare if they do not offer the same capabilities in the near future.
Backcountry off-road travel is why we are here:
The dashboard mounted guidance GPS units like the TomTom, Garmin Nuvi, etc and the OEM navigation systems are not being considered here because they offer road navigation only. If you want this capability, I would recommend buying a software package for use on your laptop or PDA. I have also left out discussion of the latest technology—ultra mobile PCs. These are basically miniature laptops; I have no experience using one and in fact I have never seen one. Look into these if you want something sized between a PDA and a laptop.
A quick note about GPS receiver technology:
You will read a lot about SiRF Star III chipsets. SiRF is the newest GPS technology offering improved satellite sensitivity and many will tout it as a “must have.” SiRF is great, but the recent 32 channel MTK chipsets feature the same –158dBm sensitivity with a fraction of the battery consumption of a SiRF Star III chip. I recommend doing some reading on your own on this matter.
What I use:
GPS survey work is part of my working career. I use a $7,000 Trimble GPS unit. This unit is basically an HP PDA with an integrated GPS receiver running Microsoft Windows Mobile 5.0 operating system and ESRI ArcPad software. I use 1:24K, 1:100K and 1:250K USGS quad maps available in every State of U.S. for free via the internet, and I also use free aerial imagery from a number of sources. I can toggle between these maps and view my current position, as well as the places I have been.
For personal use, I have identical capability with my Dell Axim X51V PDA. I paid $349 for the PDA and $69 for an I-Blue 737 Bluetooth GPS (MTK chipset). It runs the same Windows Mobile 5.0 operating system as the $7,000 Trimble, it features a faster processor (624 MHz versus 512 MHz for the Trimble), a 3.7” true VGA screen (Trimble uses Quarter VGA), an SD card slot with a 4 gigabyte card, an additional compact flash slot and two $99 software packages for navigation. I use iGuidance for turn-by-turn voice and 3D ROAD guidance (looks like the TomTom ads you’ve seen) and I use Memory-Map for off-road stuff. The latter software allows me to use the same maps and aerial imagery that I use at work, plan routes, record tracklogs, points of interest, geocaching capabilities, etc. I am very pleased with this setup; I feel it is a good compromise between screen size and portability.
Summary:
Hopefully this will make your GPS purchase decision a little easier. This write-up was meant for backcountry off-road travel in mind. If you feel that I have inaccurately represented a piece of equipment, comment away if you wish.
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Originally Posted by paddlenbike
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