A Ruler to Measure Positions and Properties on Cylindrical & Pseudocylindrical Maps

[Michael Ossipoff]

Because all flat maps mis-represent some aspect(s) of the globe, I suggest a "Position-&-Properties Ruler" (PPR) for use with Cylindrical and Pseudocylindrical world-maps.
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Oriented north-south, with its zero-end at the equator, its scales would give latitude and various map-properties at various Y points along the ruler's scales.
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And, with Cylindrical maps, and with the ruler oriented east-west, a short longitude-scale would measure longitude between the map's meridian-lines.
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Of course such a PPR could give more information on a Cylindrical map than on a Pseudocylindrical map.
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Here are the scales that I suggest for a PPR for Cylindrical maps:
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1. Latitude
2. Area-Magnification with respect to equatorial places.
3. NS/EW scale-disproportion
4. NS scale
5. EW scale
6. Longitude
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Of course a ruler only has 4 measuring-edges--2 on each side. All but one of the scales have a length equal to the distance along the central meridian from equator to pole. The longitude-scale occupies a short section added to that length, and the sum of those two lengths is the overall length of the ruler.
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The 4 measuring-edges go to Latitude, Area-Magnification, NS/EW Scale-Disproportion, and EW-Scale.
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NS-Scale is placed directly along and adjacent to the EW-Scale, with its measurement-lines extending to the edge, and of a different coler than that EW-Scale lines.
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And, as I mentioned, the Longitude-Scale occupries an additional short length added to the ruler.
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A compromise Cylindrical-Map needs all of those scales. A CylindricalEqual-Area map of course doesn't need the Area-Magnification Scale. A Mercator map of course doesn't need the Shape-Disproportion Scale, and only needs one measuring-scale for measuring map-scale, because conformal maps have the same scale in every direction from any particular point.
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Of course, for a Pseudocylindrical map, the PPR can't tell NS-scale, Longitude, Shape-Disproportion. ...leaving only Latitude, Area-Magnification and EW-Scale for a PPS for a Pseudocylindrical map. ...and of course an equal-area Pseuocylindrical wouldn't need the Area-Magnification scale, and its PPR would tell only Latitude and EW-Scale.
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Michael Ossipoff
Aprilis 10th, 2020

[Michael Ossipoff]

I should add that of course the measuring-scales that I mentioned, for latitude, magnification, NS/EW scale disproportion, etc., could be added, as part of a map, up the two vertical sides of the map, instead of on a separate ruler.

The scale for measuring longitude between adjacent meridian grid-lines could be between two meridians somewhere along the bottom of the map, or maybe all along the bottom of the map.

Adding some of those position-&-properties measurement-scales to a map would give information that a flat-map can't directly show.

Michael Ossipoff
Aprilis 13, 2020