# How Does PoleClinometer Work?

The PoleClinometer slope meter uses the shape of your pole to do its thing. The typical ski pole…

- will
**hang vertically**when you dangle it (like a plumb bob). This is critical. - has a
**cylindrical shaft**, so lines around it representing slope angles can be read from different perspectives (see below).

The trick is in the “lines”. Each PoleClinometer slope line is defined by the intersection of a hypothetical plane (representing a given slope angle) with the surface of the cylindrical pole shaft. Such a line will appear straight only when viewed from any point *on that plane*, and will otherwise appear curved, as illustrated below. See the use page for how this gets applied in practice.

Interestingly, in order for these lines to appear *straight* as viewed on the pole shaft (and to accurately represent specific slope angles) they must follow a specific *curve* when plotted on the flat sticker. These curves are where the magic happens, and defining them requires just a bit of math…

# Mathemagical Curves

Each slope line on a PoleClinometer sticker is a precise sinusoidal curve to accurately represent a specific slope angle when wrapped around a cylindrical pole shaft. If you really want to get your geek on, check out the math behind the magic of PoleClinometer curves. Otherwise, suffice it to say: **Straight lines don’t work!**

# Steer Clear of Straight Lines

There’ve been a couple attempts at ski pole inclinometer stickers that incorporate straight lines (details here). These straight-lined inclinometer stickers should be avoided as they’re inherently flawed and highly inaccurate. But I credit them as my inspiration to find a way to do it right, which led to PoleClinometer.