Originally Posted by snooker
I am wondering why Garmin sells both types? Is it just to offer a slighty cheaper set if you only needed say 1 state like Colorado?
I might be misunderstanding the question in thinking it is about 24k versus 100K, but...
One needs to remember that dual sporters are almost certainly not the main market for Garmin's mapset. It would probably be the footborne recreationalists who are the major purchasers of these mapsets. For hunters, hikers, etc, more detail in hypsography is going to be infinitely more important than a routable trail. I wouldn't be surprised if there isn't a little bit of legal defense involved: "We could be sued if somebody used a trail we put in the map that led them into danger". Sort of like handguns that have "This firearm will discharge with the magazine removed" rollstamped into the frame... But that's an aside.
I can tell you that trails are an enormous difficulty for mapping. Take a look up in Canada where Backroad Mapbooks have been providing detailed recreational maps for backcountry recreationalists for nearly 20 years now, first paper only in gazette form, now paper and Garmin mapping as well. They try to have everything - trails, campsites, paddling routes, you name it. I've done some consulting work and ground truthing for them; narrowing it down to trails, the problems are legion.
First, what defines a "trail" anyways? Some are truly foot only, man or beast. And when does a wildlife trail become a human "trail" - when recreationalists start regularly using it and it becomes known? So who finally maps the thing? Conventionally, some government agency does, normally one associated with parks or outdoor recreation. But money for those projects is nonexistent, and if it was done, they didn't hand the warden or ranger a high quality GPS. They were asked to sketch it in on a paper topo map in the course of a horseback back country patrol (been there, done that), using the contour lines, creeks, etc as a guide. Or they were handed one of the earliest Garmin GPS units to capture the trail - and nobody has been told to update the mapping ever since.
Or they relied on "local knowledge". There were posts here a few years ago from somebody wanting to know if anyone had ridden the Grease Trail, an old native trade route heading north from Ft Ware, because they wanted to ride it on their KLR. Sure enough, on maps, there is a nice straight line from Ft Ware heading north towards the Yukon. I supported a friend who wanted to try hiking it last year by making some custom Garmin maps for him. Found out very quickly that the "trail" involved some government official in the distant past asking some native guy who had been over the trail at least once on a horse to draw a line on a map.... I'm sure the native guy did his best, but I'm also sure he probably never used a map in his life and probably hadn't been on that trail (or at least in its entirety, if ever even that) in probably 20 years. Short story - they fought through swamps and alder for about 30 miles before showing the good common sense to turn around and return to Ft Ware. Said they encountered hints of trails here and there, but that's about it - the forest and bush reclaims trails and roads pretty quickly when unused.
An example of official government mapping: Banff is Canada's most heavily hiked in national parks, and Waterton nearby adjoins Glacier in Montana. Go see if you can find any digital trail information available for those parks from the government.
The explosion in personal GPS devices (particularly present day, with their enhanced reception and accuracy) has been a game changer, and neither the government nor recreationalists have responded well to it. There is no organized data warehouse I'm aware of that collects trail input with a data manager who has a system for groundtruthing submitted data to ensure it is both reliable data (or has a reliability rating) and updated as changes occur.
Backroads Mapbooks approach has been to seek data from any source they could find, not just for trails but for the billions of miles of dirt roads that access (or often just used to access) logging, mining exploration, etc. Many of the roads in their mapping (which might be what the OP would consider a ridable "trail") haven't been passable even by foot for over 20 years now. Alder hell... So you have a problem in that sources will give you mapping data - but while people will add mapping data, RARELY does anyone get sent to remove road and trail features when they are no longer passable as roads and trails.
So when you're Garmin (or Backroads Mapbooks or a similar company) what do you do? Your GIS/cartography employees have had it drilled into them from Day One in their profession that mapping information must be reliable. You can't groundtruth the whole bloody country like governments do with gazetted highways, public roads, streets, etc. The question that nobody has fully resolved yet is how you collect reliable trail data that you're confident about putting in your maps. Look at all the posts we see here where somebody was pissed because a road that supposedly went through turned into a dead end, or now had a fence running right across it somewhere with "no trespassing" signs.
To end a long story, until somebody decides to take the initiative to formalize a means of collecting, groundtruthing, and updating/removing trail and non-public road data, companies are never going to be able to provide uniformly satisfactory data for those features in their mapsets. A trail on slick rock in Utah may have been there for a thousand years and be reliable when mapped for the next thousand. But in Washington, Idaho, Montana, etc, old mining and trade trails disappeared a decade after falling into disuse.
In my view, the most reliable source for trail data is going to be private, cooperative websites like http://www.dualsportmaps.com/
. It happens to be dual sport riding specific, unlike websites like http://www.gpsies.com/?language=en
which warehouses tracks for hiking, horses, mountain bikes, you name it.
My take - with my recreation being in NW Montana through SE BC - is that the 24k maps are far more valuable than the 100k maps due to the far more accurate hypsography and natural features. I have no interest in routable trails or roads for a variety of issues. The enhanced natural features of fine scale mapping really assist in orienting yourself to your surroundings when you're somewhere in a maze of old roads, new roads, and sometimes no roads.
The tracks don't have to be in the mapping for my Garmin, at least in my view. It sure would be nice if they were, but I can go get them from a place like DualSportMaps, where somebody actually rode the trail, made comments, attached pictures, points of interest, etc. And where people who later rode the trail added commentary on the accuracy, updates, etc. I know a track in DualSportMaps is going to be far more accurate for dual sporting than anything that Garmin can come up with, given their necessary generalist approach to mapping.
The moral of the story is: get the mapping you'd like to have by collecting and sharing the mapping you'd like to have. Think on this for a moment: if every ADV member riding with a GPS collected and submitted GPS data from the tracks they ride off public highways (ie the data Garmin and others have a hard time collecting and ground truthing) to a website like DualSportMaps... how long do you think it would take to have a truly comprehensive GPS datawarehouse of the dual sporting available?
I've been uploading and mapping the crap out of the best dual sport riding in SE BC for that very reason, and I suspect others have been doing the same with popular riding around places like Colorado and Utah.
One final note: Backroads Mapbooks http://backroadmapbooks.com/GPS/index.html
realizes that much of their collected road and trail data from governments, forestry companies, etc is unreliable or no longer in existance. Their approach to getting road and trail data current and reliable as possible is this: purchasers of their products who submit trail and road corrections, new roads, new trails, etc get free map updates for as long as they continue the process of submitting corrections and updates. Most purchasers probably don't bother, but there's an example of where at least the users of the product have an opportunity to improve the areas they use that they see shortcomings in.
There are other private recreational Garmin mapping providers throughout North America at least, and some of them probably do the same as Backroads. Between that and websites like DualSportMaps, it seems to me that the quality of the GPS mapping available to dual sporters (and hikers, mountain bikers, etc) is in our own hands. Instead of just (correctly) complaining that the mapping for our Garmins lacks what we need, we can do something to change that.
BTW, just for clarity, I have no financial or other personal interest related to any company or website mentioned here, other than the fact I've paid for and use their products when they are for sale instead of free.