Spire measure: Frequently Asked Questions

• Q: Why is it called "spire measure" when it measures lots of things other than spires?
  A: The name "spire measure" is certainly not perfect. However, it is supposed to be suggestive, not limiting. First, spire measure actually can be applied to any feature on the Earth's surface, be it a mountain, plateau, cliff, or rock spire. The name comes from the comparisons spire measure makes: given two peaks or features of roughly "the same size," the one which is more spirelike (steeper and/or pointier) will get a higher spire measure. However given a small peak with a classic spire shape and a much larger one which is not particularly steep or pointy, the larger peak can get the higher spire measure, simply due to its size.
• Q: Are there alternative names for this notion?
  A: The notion of spire measure originally went under the name "impressiveness," but this was felt to be inappropriate, as impressiveness is a highly subjective and variable notion. Other possible names are "precipicity," suggested by Mike Cleven, and "LRS," short for "local relief and steepness." The former is, I think, just about as liable to misinterpretation as "spire measure," since it sounds like it only measures cliffs; and I dislike the latter on the basis of avoiding acronyms where possible.
• Q: Why does (insert favorite peak here) come out poorly (or get beaten by some other peak) on your list?
  A: Remember that spire measure, while roughly correlating with visual impressiveness, is not going to agree perfectly with everyone's idea of what the "best" peaks are. It certainly does (very intentionally) slight a great many high-elevation peaks, ones with either little local relief or little steepness. If your favorite peak seems unfairly slighted, think carefully about what its local relief and steepness are, whether it has a very broad summit (hence not pointy/spirelike), and whether it lies next to a peak which may fare better in terms of spire measure. A little thought in this direction usually explains the apparent unfairness.
• Q: But what about (insert particularly pointy/steep peak here)? It seems to be the epitome of spirelikeness, but it doesn't appear (or isn't ranked highly).
  A: There are some peaks which have some very steep terrain (maybe a steep technical climb to the summit) but which do not rise as high above the local terrain in general. Often peaks which are in the heart of a range are like this---the Palisades come to mind. They are beaten by Mount Tom (see the Contiguous US Top 50 List), which does not appear as "spirelike" to most people, since it does not have the steep part at the top which the Palisades do. But Tom is closer to the edge of the range, and hence to low terrain, so it comes out very well in terms of local relief.
  There is a tradeoff involved in setting up spire measure between "slopism" (favoring steepness) and "heightism" (favoring large relief). Spire measure makes this tradeoff in a particular way (chosen for elegance and simplicity), which will not accord exactly with everyone's personal opinion. In particular, technical climbers tend to be very slopist (more so that spire measure) while hikers tend to be heightist. Spire measure works out somewhere between the extremes. If you find yourself not agreeing overall with a spire measure list, it is likely to be because you are significantly more slopist or more heightist than spire measure.
• Q: But my favorite peak is not even on your list! I admit it won't top Peak X in terms of spire measure, but it should appear!
  A: If the list is ranked by reduced spire measure, or has a reduced spire measure-based cutoff, then the explanation is that your favorite peak is probably quite close to another peak which is superior in terms of spire measure. Reduced spire measure then treats your favorite peak as a subpeak of the superior one, which is liable to greatly reduce its RSM.
• Q: Why bother with reduced spire measure at all? Spire measure measures what I want (roughly) and it's complicated enough already.
  A: Spire measure is like height in that it assigns a value to every point on the earth's surface that varies continuously as you move the point. If we want to make a finite "Top N" list, you cannot use any measure like that, just as you cannot use pure height to make a list without imposing some sort of cutoff. Reduced spire measure is like prominence, in that it only gives good values to a finite set of points, which can be put in a list. See the spire explanation page or the explanation of prominence on the main peaklist.org site.
• Q: How can I calculate this on my own?
  A: There is a feature for calculating (unreduced) spire measure built into Edward Earl's Winprom program. Currently this is the only publicly available implementation of the spire measure algorithm.

See the explanation page for a more thorough treatment of many of these issues.

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