At Nome Alaska-- KOME-- the E2 airspace (dashed magenta line) is listed as extending 13.2 (nautical) miles east of the airport-- according to this source page E-9 -- https://www.faa.gov/documentLibrary/media/Order/JO_7400.11C.pdf --
"Within a 4.1-mile radius of the Nome Airport and within 3.4 miles each side of the Nome Airport 106° bearing extending from the 4.1-mile radius to 13.2 miles east of the airport..." 'AMENDMENTS 07/07/05 70 FR 22590 (Revised) Corr: 70 FR 33349""
But when I measure on the online sectional chart http://vfrmap.com/?type=vfrc&lat=64.513&lon=-165.444&zoom=10, using the tic marks on the lines of longitude (the lines running north and south) as a scale equal to nautical miles, the far edge seems to measure more like 15.5 nautical miles from the middle of the airport symbol (as shown by the little blue square) -- now why would that be? That's about 20% further -- about 2.3 miles different -- not insignificant.
What is going on here?
Is the scale wrong, or is the dashed magenta line shown in the wrong place, or is the airport shown in the wrong place?
I assume "east" in the above usage means "generally east, measuring along the 106-degree radial".
It's not a one-time thing, I'm getting a similar discrepancy with some other similar measurements of other similar regions of Class-E-to-surface airspace, always biased in the same direction.