BaseCamp routing cars on trails?

This may be a more general issue with the Garmin routing engine, but I just got and am playing with the 24K maps for my region (west) and generating routes can be a little wonky -- like asking me to drive on a trail??

(This is with BaseCamp 3.02 on a Mac, using TOPO 24K West v2.0)
Specifically, I was looking at going to a trailhead in the Emigrant Wilderness, at N38.17896 W119.90773 (the Crabtree trailhead). Oddly, the trailhead is not shown as being next to a road (but from experience and other maps, I know that it is). The road does go to another trailhead which connects via the trail network to the one I want.

So I use the route tool, with preferences set to "car/motorcycle", and use the trailhead at one end and my house at the other.

The route I get from BaseCamp follows the road, then happily takes my car onto a trail and drives on the trail to the point that I want. I think that neither I nor the Forest Service want my car going on these trails. (This is the first screenshot, although it's hard to see that the route goes from road to trail.)

My expectation was something along the lines of getting my car close to the trailhead on the road and then doing a direct route, or just saying that it couldn't go there -- but taking the car on the trail is NOT expected or desired!

2) Computing a route for another wilderness trailhead (Quartz Mountain, near Yosemite: N37.53096W119.44422), I tried to use the "Avoid unpaved roads" option -- there are many ways to this particular trailhead on a twisty maze of forest roads, but some of these roads are paved and some are not and some are REALLY beat up.

Attachment #2 shows my route when "Avoid unpaved roads" isn't checked; it follows a regular road, then drives down an unpaved road to the actual trailhead (which is necessary for the last bit; there's no way around that, I just want to avoid unpaved roads as much as possible).

When I change the routing preferences to include "Avoid unpaved roads," BaseCamp happily does so... by putting me onto a trail again! Apparently a trail is better than an unpaved road, and that just seems... wrong. (See attachment #3)

I have to admit, this has me a little scared to try the routing in the woods...

To summarize:
- BaseCamp (or the routing engine in general) seems like it treats roads and trails as equivalent for car/motorcycle routing, and it shouldn't. Cars/motorcycles just don't go on walking trails. (Yes, there are OHV trails, but I hope those are delineated differently!)
- BaseCamp treats trails as *preferred* to unpaved roads when routing cars/motorcycles, and it shouldn't.

0 Former Member over 15 years ago

It looks to me like you're pushing the mapping data beyond realistic expectations. Typically, auto-routing is used for established streets and highways, using maps that primarily show the same. The kind of navigation you are doing is really off-road, even if you are driving part of it. Which means you should be drawing in your own tracks and/or routes, not relying on an algorithm.

The other problem you may encounter is that the mapping data is out of date. A forest road gets washed out in a storm some years ago. The map, being of the backcountry, is not updated. The road may be passable on foot, may not, but again, the map won't tell you. The answer is what you might expect: local info, a call to the ranger station, a more recent map. There's a Custom Map section on this board that addresses the last of these. Creating them is rewarding, but takes some skill.

0 azdrmn over 15 years ago

Thanks for your feedback. We will look into this.

0 PSEABOLT over 15 years ago

I have the 24K maps and find the routing on trails to be one of my most used features. I have to force the routing it to follow the trail by clicking on the trail start and end. If the Trail; crosses roads I have to insert via. I can force it to follow the trail much easier than I can use the tracking tool to draw the track. With the 24k maps you can build an elevation profile from a route. I had never had a problem with BaseCamp wanting me to drive on a trail for a car route but I prefer city navigator with more POI and Address look ups.

Maybe tweaking avoid unpaved roads is a solution but please don't kill this great feature.

0 Former Member over 15 years ago

I have the 24K maps and find the routing on trails to be one of my most used features. I have to force the routing it to follow the trail by clicking on the trail start and end. If the Trail; crosses roads I have to insert via. I can force it to follow the trail much easier than I can use the tracking tool to draw the track. With the 24k maps you can build an elevation profile from a route. I had never had a problem with BaseCamp wanting me to drive on a trail for a car route but I prefer city navigator with more POI and Address look ups.

Interesting. Are you able to transfer the data to your GPS? If so, is the result a route or a track?

0 PSEABOLT over 15 years ago

Interesting. Are you able to transfer the data to your GPS? If so, is the result a route or a track?

I have never tried but I am sure it would be a route. We never hike enough to need anything but the trail that appears on the 24k maps. The show elevation profile is available for any route and map but if you select it from city navigator nothing happens. If you select show elevation profile from a map that has elevation, even the 100k maps you get the profile. I am pretty sure a route following a trail is no different from a route following an interstate. I use the show elevation profile for roads as much as trails. When riding a bicycle, I find elevation profiles to be some of the most useful information you get from BaseCamp

0 Former Member over 15 years ago

I just found this review of the 24K series from gpsinformation.net. Looks like you can indeed download auto-routes to a GPS. The author does note (to this thread's original point) that "while you may get a route showing you to a destination, it doesn't mean you can drive a car there. Some roads on the map indicate a solid gray line, but these roads can be dirt and in some instances, a 4X4 vehicle may not be able to travel on it. Some dotted line trails may also not even support an ATV and are only for hiking." He does think the routing preference--car/motorcycle, bicycle or pedestrian--matters. But apparently not enough.

If you don't have the 24K series or if you plan to go cross-country, you can still get an elevation profile by hand-drawing a track that roughly traces the route you plan to take. As you point out, a map with elevation data is still required. FWIW, I'm using a combination of Topo U.S. 2008, Custom Maps using raster data (thank you, Garmin), and a highly detailed vector map of California available free from GPSFileDepot. I can see where the 24K might make sense in this mix. Except that when I look at the View Map preview tab for TOPO U.S. 24K West, Point Reyes National Seashore shows trails (unnamed) for only part of the park. MIA: the most popular hike in the Seashore. As usual, in my experience, the best trail maps are still raster.

0 steverodrigues over 15 years ago

Speaking as the OP, the routing type does matter -- the system picks different routes based on whether or not I'm a pedestrian or a car (I didn't try bicycle); it seems to not want to take pedestrians on freeways, which can yield some pretty funny results if you're not paying attention. :)

My point was primarily that just as pedestrians don't go on freeways, cars don't go on walking trails. Especially not when trying to avoid unpaved roads!

While I agree with PSEABOLT that I'd rather have routing on hiking trails than not, I'd also rather not get directed onto something that is obviously not intended for cars and that the mapping data knows is not intended for cars. (There are errors where trails are marked as unpaved roads; these are not one of those cases.)

As for the quality of the mapping data: Yes, I do double-check the validity of my map, and I call the Forest Service or check their website for up-to-date road information. But none of my examples are rarely-used; they go to busy trailheads that are full all summer long, they've even got status entries on the Forest Service pages. (And the mapping data matches with the physical topographic maps I've got -- raster maps don't offer any advantages here!) They're just not all paved roads, and they're not as well-signed as I like -- which is why the routing comes in handy.