Help a sort-of newbie choose a GPSr?

[Taiko-ma]

Hi!

I just found this forum, and I'm hoping I can call on the member's expertise and considered opinions.  I'm shopping for a new GPS unit and, though I used an aviation unit for several years as a Flight Medic, I'm pretty much starting cold with raster maps and Mapsource and GMX files   I've tried to research this, but honestly I could use someone more fluent in the language.

First, my particulars.

Needs/Wants, in general order:
• For hiking and general traveling, NOT interested in driving or turn-by-turn capabilities as a primary function.
• Reliable in forest cover/trees/hills
• Ability to load topo maps, general road maps, aerial, with large capacity (ie SD card capability)
• Using replaceable batteries (such as AA), rather than rechargeable
• Ability to load maps of areas outside USA: Belize this summer, and possibly Africa or Peru in a year or two.  Both topo and road; overlaying would be ideal.  Ability to add POI also would be good.
• Ability to get more maps without selling my right arm ($100-120 for a regional set of topo maps?   Ouch!), and/or load my own maps from websites
• Barometric altimeter

NOT needed/concerned about:
• Voice directions, turn-by-turn driving, etc
• A particular interface: touch screen vs buttons vs dial isn't a big deal as long as they work
• Definitely not interested in geocaching
• Cameras, sound recorders, games, hunting schedules, etc


I've pretty much narrowed the selection down to either a DeLorme PN-40 or a Garmin Oregon 300 (and buying the mapping software, rather than having the maps installed on the 400t, so that I can set waypoints/routes on my PC then upload).  I like the PN-40 mostly because of it's aerial photography, overlay capability, and the $30/year all-you-can-eat downloads (although it's pretty much USA only, which is a minus).  I know this is a Garmin-friendly site, so what thoughts do any of you have?

Also, what size of 1:24K or 1:100K map can I fit on a card?  Are we talking a square mile per GB, or Alaska+Texas and then some?  And if I go with Garmin, am I on the right track with the 300 vs 400 for accessing the maps through PC software?  Software recommendations?

Thank you in advance for your help.  I'm looking forward to perusing the site and, who knows, maybe even knowing enough to contribute some day!

Peace,
Taiko-Ma

[Boyd]

Just a few thoughts. No experience with the PN-40 although I know there are many happy owners.

I don't own any of Garmin's 24k maps, but they are not "real" USGS maps, they are vector based maps which contain routable roads and presumably that Navteq data is one reason for the high cost.

If you want raster based maps on the Oregon, you must make them yourself. There are several ways to do this, and it isn't terribly difficult or expensive, but it takes some time and trial/error. You are also very limited in the amount of area which can be covered with these maps. Storage won't be an issue with Garmin raster based maps - the largest one I have been able to create was about 35MB and you can only have ONE of these on the GPS at a time.

Presumably Garmin has created these limits to prevent competition with their own products. Some quick math: 1024x1024 is the maximum map tile size and you can't have any more than 100 tiles. So in round numbers, your image can be about 10,000x10,000 pixels. If you want 1 foot per pixel resolution then that gives you about 2x2 miles. With trial and error, I found that when using USGS 24k topo maps you could have coverage of a 20x20 mile area with acceptable quality. Look at some of the maps I've made here. For the most part, they push the limit of Garmin's spec in terms of coverage area and resolution: http://www.gpsfiledepot.com/maps/byuser/282/

So that's about it for raster based maps. Vector based maps are another story, and they are more time consuming to create although that is the primary focus of this site. FWIW, US Topo 100k is a total of about 3GB. I have an Oregon 400t which has the preloaded map. With almost any Garmin GPS, there is a limit to have many map segments (the tiles that make up vector based maps) you can load. Older models max out at 2025 but the Oregon can handle 4000 segments. US Topo 100k on DVD contains more than 6,000 segments. So regardless of how large a memory card you purchase, you can't load it all on the Oregon 300. The version that is pre-loaded on the 400t has much larger tiles and only uses about 400 segments. Also realize that the segment limit applies to the sum total of all the maps you have loaded on your unit, not just the one you are currently using.

[maps4gps]

DeLorme has about a 2 year lead in units displaying raster images.  Their downloadable data is convienent, however I believe it is just the 1m resolution data that is free for download from USGS.
There are also many other types/resolutions of raster data you can download from USGS and other Government sites.  As Boyd mentioned; the max size of the image is currently limited; I do not kinow what image size limit the DeLorme units might have.

You can purchase software from DeLorme to create your own maps.  I do not recall if there is a site hosting 3rd party maps created for their units.

My 76csx and Oregon300 use standard size AA batteries - I do use rechargeable AA's.

You can have a map of anywhere - if someone found a data source and created the map.  The openstreet project/cloudmade has routable maps of much of the world (at some level of detail and completeness) where data has been contributed.  Satellite images at 15m resolution are available for most of the planet; however, I would estimate only about half of Belize would currently fit within Garmin's pixel limit.

Sometimes it just comes down to which unit feels better in your hands.

[Indrid Cold]

  I like the PN-40, but for international travel I would and have personally only used Garmins. You can overlay vector on raster with several of the Garmins now, and the map limit on DeLorme is 256 (the unit uses something like 30+ of that limit for it's basemaps).

  I'm not even convinced DeLorme has ever manufactured their labeled GPS receivers themself, I'm under the impression they imported from a third party electronic manufacturer, and this has lead to quality control issues that are beyond their control. I wouldn't want to be in the rain forest with a unit that loses it software because the batteries ran flat.

  If you go the PN-40 route, you are going to want to get their xMap software, and I would also highly recommend getting Global Mapper. And bring a lot of AA cells if you don't plan on using rechargeable batteries. Doing the math, you might find that getting a Oregon 550 would end up costing less over three years just in battery savings.

One of my favorite quotes on their subscription service:

The $30 per year subscription is like an "All you can eat" buffet. That only serves soup. By the teaspoon. And you have to drink it through straw  I'd rather go to the sandwich shop next door and get a complete meal.

[Taiko-ma]

Thanks for the quick responses!  I've also dug through the site and found the map-making tutorials, so I'm going to spend the next several days just absorbing.

After perusing this and other sites, it looks like Garmin is the way to go due to the overwhelming number of mapping programs, maps, and standards that go with Garmin.  Now I just have to decide between the 450t and 550t...such touch choices

Peace,
Taiko-ma

[Indrid Cold]

I was looking at some vector data for Belize today, would be easy to format it for a Garmin.

[Taiko-ma]

Sorry for the delay; school has been keeping me busy.  I appreciate the replies.

So I have a 550t on the way, and I've checked out several dozens of types of mapping software...and now I'm scared

Is there a good step-by-step tutorial on how to make vector maps?  One thing I would like to be able to do is take a satellite image from Google Earth (or other electronic map), plot a route/add waypoints, then load that onto the GPSr.  Most of the info I've seen so far is focused on the exact opposite: uploading your already-traveled routes onto Earth.  I'm willing to purchase the necessary software, I'm just not sure what I need.

Again, thank you for all your assistance.  Hopefully my ears will dry quickly once I get some hands-on time 

Peace,
Taiko-ma

[Seldom]

http://www.gpsfiledepot.com/tutorials/

This page has the most systematic tutorials I've seen.

[Boyd]

Well first you will probably want to make a custom (raster) map of the area. Have a look at these programs:

http://topofusion.com/garmin-custom-maps.php
http://moagu.com/?page_id=155

Making vector maps can be complicated. You might find that a track and a group of waypoints could do what you want when overlaid on the image. These can be created with a variety of tools, including mapsource or basecamp. Really, any program that can read and write .gpx files could probably be used for that.

But if you want to create a "real" vector map, then Mapwel is probably the most user-friendly program. It can do everything, as opposed to other solutions which require one program to create the map and cgpsmapper to compile it. You can play with the free demo to see if you like it:

http://www.mapwel.eu/