3D Ski Maps With Color Mapped Steepness
A 3dSkiMap is a 3-dimensional model of a ski area with an image overlay having the steepness or slope of each point coded with a color from a graduated scale, with green designating the least amount of slope, changing gradually through blue, to red, to yellow which designates the highest amount of slope. An orthographic aerial photo of the ski area overlays on top of that to show the location of wooded and impassable areas, as well as man made features.
The overall effect is to give the user a general idea of the steepness of an area at a glance, and to give a clear picture of the changes in steepness of a particular trail or piste.
Traditional ski trail maps depict the difficulty of trails with colored lines: green for Beginner, blue for Intermediate, black with a diamond for expert, and black with two diamonds for most expert. This is alright, but it doesn't tell you, for example, that an Intermediate trail might seem to be the same difficulty as a Beginner trail except for one difficult area in the middle.
Not only that, but various ski areas seem to have their own scales for trail difficulty, with an Intermediate piste in one area equivalent to a Beginner piste in another. This was what gave inventor Dale M. Greer the idea for 3dSkiMaps in 1999.
3dSkiMap is a trademarked term of 3dSkiMaps, LLC.
About The Data
It's just the free stuff, so data points are 10 meters apart. Slope values will be under or overestimated for features that are smaller than 10 meters.
I haven't been to most of the places I've mapped, but I know there's a place at Taos that's way off because it's a Beginner trail but the data points fell at just the wrong places so on the map it looks like 40 degree incline. Catwalks hardly ever show up because most of them are narrower than 5 meters.
Think of it like a blurred image of what the slopes really should look like, so any peakiness will be smoothed out, but the overall picture will still be helpful. Your speed on the mountain will be between 3 and 30 meters per second, so somewhere in between that speed you will traverse the USGS data points in one second or so, you might hit a rise or a dip between those points, but from one point to the next the slope will be accurate.
To me this is more like 3dSkiMaps 0.9. I'll consider it 1.0 when I can get money to buy 1 meter or finer data.