Multiple elevations achievement

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This proposal is intended to supersede the Over and under achievement proposal and Stacking achievement proposal, which both received general support in 2009 and 2010, but were never made valid achievements and were suggested to be merged.

This is a proposal made on 2011-10-04. Please leave comments and suggestions on Talk:Multiple elevations achievement, indicating whether you:
  • Support the proposal
  • Do not oppose it
  • Oppose (this option requires you to watch the page and return to comment on modifications), or
  • Think it Needs work before you can decide.

See Proposed achievements for more information on this process.


Mostly from the Over and under achievement

To claim this achievement alone, a geohasher must occupy the same hashpoint at two or more significantly different altitudes on the correct day.

The level of achievement gained depends on how many significantly different altitudes were reached that day.


Mostly from the Stacking achievement

To claim this achievement in concert with other hashers, the geohashers must simultaneously occupy the same hashpoint at two or more significantly different altitudes on the correct day.

The level of the achievement gained depends on the number of hashers at different altitudes involved.

Positioning of the Geohashers[edit]

To be significantly different, the altitude difference must fall outside the margin of error of your GPS. This requires each hasher to reach their altitude independently (i.e., can't stand on each other's shoulders).

The usual allowance for GPS inaccuracy on the horizontal plane does not apply if it can be proven from a map that the stacking was impossible. For example, if geohasher A stands at the bottom of a sheer cliff, and geohasher B stands at the top, the achievement can easily be disproved by use of a map, even if they are only 1m apart in a bird's-eye view.

Because GPS altitudes can be more inaccurate than lat/long positions, if the positions are clearly a good distance apart as shown in a photograph or other proof, the award can be claimed.


  • A photograph showing how the stacking was possible (e.g. a photo of the outside of the carpark, or of the bridge showing the path underneath).
  • Plus:
  • A photograph of each geohasher at each level, and/or
  • A photograph of each geohasher's GPS. As altitude measurements on GPS devices aren't very accurate, an alternative could be the GPS photographs showing the exact same time, or
  • OR a convincing story if the GPS cannot provide proof (e.g. one geohasher was underground, or one geohasher stood on a road bridge while another drove underneath)


  • A bridge over land would allow a level 2 stacking achievement, as would a tunnel through a traversable hill.
  • A hashpoint in a multi-story carpark or a building staircase would afford a multi-level stacking.
  • An apartment or office building with multiple ambassador achievements would also allow multi-level stacking.
  • A simultaneous air and land geohash would be the ultimate but hard to prove!


A sample gratuitous ribbon created by Michael5000 for the Over and Under Achievement:

Over and Under.png
Michael5000 earned the The Over and Under Achievement
by reaching the same hashpoint at two different elevations (45, -122) geohash on 2010-08-05.