What are directional, height, and distance guidelines for marking trails?

Question

Generally, I'm more used to methods described here for the US.

Our task this past weekend was to use dots to remark a trail, but the method of placement was opposite to what I'm used to: the dots were placed inward toward the path - only one dot.

I questioned the wisdom of such placement, but the ranger was adamant: one dot placed facing the trail in a perpendicular fashion. He affixed the first marker to be sure his point was made.

So he seemed to be following advice more or less offered here.

Is there ever a good reason to place markers facing the trail, rather than facing the direction of walk?

What about height and distance - how far apart should blazes be posted?

Answer 1

Here is the National Park Guidelines to your questions,

Blazes are placed on trees or posts, slightly above eye level so that hikers can see them easily when traveling in either direction. In areas where the trail receives winter use, blazes are placed higher so they are visible above the snow. Blazes should be within "line of sight"—when standing at a blaze marker, the hiker should be able to see the next one. Blazes should be placed on trees that "strike the eye.” One well placed blaze is better than several that are poorly placed.

Blazes should be continuous—even along road segments and other unmistakable parts of the trail. Blazes should be placed immediately beyond any trail junction or road crossing—even if there is a directional sign. A second blaze (for safety) should be placed within another 50 to 100 feet. Otherwise, it is not desirable to have more than one blaze visible in either direction at any one time. However, exceeding 100 yards between blazes is not desirable. Striking a balance so as not to "over-blaze" or "under-blaze" is the key. (An exception to the continuous blazing policy occurs in ROS primitive areas where blazing is not generally allowed.)

Source

As for whether to do parallel or in line with the direction of travel, the important this is that they be seen in both directions, otherwise one could follow the blazes out and then not back again. Sometimes one blaze would be enough and could be parallel but in others two would be needed.