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Looking at the August 10, 2023 edition of the San Francisco VFR sectional, M45's displayed name is being changed from ALPINE CO to ALPINE COUNTY:

enter image description here

More ambitiously, it is apparently going to be moved about 1700 feet west overnight!

Assuming they are not actually going to move the airport, this leaves me to wonder how precise the placement of airports on VFR sectional charts are meant to be.

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  • $\begingroup$ Is it perhaps just a correction of what had previously been mis-plotted? Maybe using the east-west portion of the creek (just above the letter "A" of "Alpine County" in the lower graphic) as a reference, is the north end of the runway more accurately plotted in the newer version? $\endgroup$
    – Ralph J ♦
    Jul 29 at 19:22
  • $\begingroup$ @RalphJ Could be. If that's the case, that would be a good answer to my question, or at least part of one. Though the coordinates in the chart supplement haven't changed. $\endgroup$
    – Chris
    Jul 29 at 19:44
  • $\begingroup$ @RalphJ Looks like that's the case! It does make me wonder why the coordinates in the CS haven't changed in concert, though. $\endgroup$
    – Chris
    Jul 29 at 20:09
  • $\begingroup$ Lucky guess, rather than knowing anything about anything about that airport or this particular NOAA charting standard. Pretty cool that Google Earth gives us the sort of precision to see things as precisely as you were able to measure it. $\endgroup$
    – Ralph J ♦
    Jul 29 at 23:11

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Per @RalphJ's suggestion, I measured the distance from a landmark (specifically, the kink in the river NE of the A in Alpine) to the runway in Google satellite view:

enter image description here

(Image from Google maps, Imagery ©2023 Airbus, Landsat / Copernicus, Maxar Technologies, USDA/FPAC/GEO, Map data ©2023)

This gives 8300 feet, and measuring the same distance in the new chart it is also 8300 feet. So this appears to be a correction of a previously incorrect location for M45, and not a shift just for cartographic convenience or anything like that.

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