Sunday, March 8, 2009

PN-40 Review - Maps

If you are anything like me, you still feel the need to carry a paper topo map, when you can get one, for all bushwhacks. I've had two previous GPS units, and neither of them got used for actual navigation, just for marking locations. A bushwhacker needs to see the big picture to spot plan a new route, and that just isn't possible on most GPS units. Furthermore, many older GPS units lacked topo maps, and most newer ones have vector graphic topo maps are are less detailed than the USGS topo quads most bushwhacks know and love. While I don't think the PN-40 should replace paper maps completly, the map support on the PN-40 is the first GPS that I'm comfortable navigating with without the map in my hand. Sure, It'll be in my backpack, but...
DeLorme is first and foremost a mapping company, and it shows on the PN-40. The PN-40 can display raster images (photos, not lines) in addition to vector maps, which is a huge improvement in the handheld GPS world. DeLorme offers USGS 24k topo quads, sat 10 low-res color aerials, b&w as well as color 3DTQ aerials, high-resolution city aerials, and NOAA navigation charts for the PN-40. They sell them through an internet based extension to the TOPO7 software called Netlink, and offer a VERY affordable $29.95 yearly subscription plan to download whatever you want. The USGS topo quads are the primary reason I bought the PN-40, because I can only carry so many paper maps, but my PN-40 can carry a whole state on an SDHC card. The ability to have actual images of the actual USGS topo quads on the PN-40 is what, in my mind, makes the PN-40 the ideal bushwhacker GPS. The maps are high quality scans, and the integration of the different types of map data at differing zoom levels works very well. The aerial images are nice, but since most bushwacking areas have heavy foliage, so they just aren't as useful as the USGS topo quads.

Oh, and by the way... DeLorme includes 100k vector topo maps in the box with the PN-40! This is a big improvement over Garmin's system where you have to buy these maps separately, or pay extra for a unit preloaded with less detailed maps than what their software provides. The PN-40 comes with these vector maps in two formats: first, the TOPO7 DVD has the uncut source files, which provide vector maps for TOPO7, and can be cut for the PN-40; second, it comes with three pre-cut map DVDs that require nothing more than the USB cable, a computer, and the DVD. I don't use the vector topos much since I love USGS topos, but hey, they're included.

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