Standard hex size on geo maps

Rock SgtDan

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HexDraw generates "perfect" hexagons....Then I alter the aspect ratio to match 8:22 (or 16:11 for Fort boards) so that the final product aligns with standard boards. At 400 dpi, a file that is 3200 x 8800 pixels shows no distortion discernible to the human eye.
Still want to know how it was done prior to digital computers. Can you use a lens to alter the aspect ratio of a negative, ie change only one dimension, when printing? Does your software tell you the amount of distortion when you alter the aspect ratio?
 

Rock SgtDan

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I was surprised to see that (as of 1959) this is exact... Knowing that the meter is defined in terms of basic physical properties, I assumed that the 25.4 conversion was only an approximation. Who knew that the yard was redefined in 1959 so that this conversion is exact?!
Interesting - got a link to an explanation of why & how it happened? What was the value before? Did the impetus come from astronomers or ICBM builders? Did the International Geophysical Year of 1958 reveal problems when they tried to reconcile all that data?

Now I want to find out when the "modern" official yard was codified and who kept the Prime Standard.
 

Gordon

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Still want to know how it was done prior to digital computers. Can you use a lens to alter the aspect ratio of a negative, ie change only one dimension, when printing? Does your software tell you the amount of distortion when you alter the aspect ratio?
I seem to recall that there was a General article at some point that talked about the process of hand painting the original boards. The hexagons were an acetate sheet that was placed over the canvas and the artwork was painted by lifting the acetate, painting a feature and then dropping it back to check position. A lot of the terrain symbology (woods, brush, marsh) were dry transfers. I'd guess that the original hexagons were just laid out in their distorted form.
 

Gordon

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Interesting - got a link to an explanation of why & how it happened? What was the value before? Did the impetus come from astronomers or ICBM builders? Did the International Geophysical Year of 1958 reveal problems when they tried to reconcile all that data?

Now I want to find out when the "modern" official yard was codified and who kept the Prime Standard.
The U.S. is "technically" on the metric system as all the old imperial measurements are officially relative to their metric equivalents. 'mericans just can't handle the truth so we don't talk about it.
 

Paul M. Weir

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The original definition of the inch was the length of 3 dried barleycorns laid end to end. https://en.wikipedia.org/wiki/Inch

I don't have sources about the inch to mm conversion, but I remember as a small child reading some old conversion tables that my mother had from her school days and they gave 1 inch = 25.3999 mm or something similar. From Wiki the US inch worked out at 25.40005080 mm. The US, English and Scottish inches were all fractionally different and the standards (bars) were found to be measurably unstable whilst the meter standard was more stable.

The U.S. National Geodetic Survey adopted the exact 1" = 25.4mm in 1893, though older definitions remained in use for a long time. Eventually in 1959 there was an international treaty defining the inch as exactly 25.4 mm.

https://en.wikipedia.org/wiki/Mendenhall_Order will give an idea of the problems.

As the metre is defined as a multiple of the wavelength of a Xeon-86 emission line, there is no need for standard bars which can vary or be destroyed.
 

Rock SgtDan

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Don says the boards were sized to fit into the boxes. Doesn't know about the draftsmanship to create the skewed hexes though.
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No you read the WIKI wrong, the US Survey distance is still the OLD, not exactly 25.4. They didn't want to mess with existing boundaries or maps. Thus the "statute" mile.

Impetus to change was invention of a physics-based standard in the 1920's, and discovering that the physical standard was shrinking by 1/10^6 a year due to stress relief in the bronze. We followed England a couple years later when the treaty signing caught up.
 
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