Great Circle Maps

The technical term for this map projection is azimuthal equidistant. A straight line from the center of the map to some other point lies along the great circle path to that point, which happens to be the path followed, usually, by HF radio waves. For more information about the merits of this presentation, see The KI Edge by Tom Frenaye, K1KI, in June 1984 QST.

SkookumLogger displays a great circle map with a number of optional overlays. These maps are only useful when they are centered on a known location. This page has a selection of links to maps for different locations, with the location information embedded in the image file. To use one in SkookumLogger, download it to your computer and use the Maps ▶ Change Great Circle Map command to load the image file.

I create the maps with the Geocart application using three databases. The map background is (as of April 2016) based on the Natural Earth database with a 21600 by 10800 pixel representation of the earth. The other two databases are “intl borders”, which defines the country boundaries, and “provinces”, which defines state/province boundaries. Geocart projects these data into a azimuth equidistant map using a unique algorithm that yields amazingly clean results. The final map is a 3240 x 3240 image in compressed TIF format.

Contact me with your geographic coordinates or Maidenhead locator if you need a map added to the list below. The file names below use the call of the requester when the call reflects the general location for the map, and otherwise a name for general geographic area. The Maidenhead locator coding for the map center coordinates is show in parentheses following the link. For maps at this scale, matching the first four characters of the locator is close enough.

2EØPPM (IO91ou)

Berlin Germany (JO62nk)

BG5EEF (PM00jp79)

CT1DRB (IM58ko)

FM5DN (FK94lp)

Frankfort Germany (JO40fc)

G6NHU (JO01ou61)

GØDVJ (JO02ma)

HB9CEY (JN37uk)

JE6RPM (PM52hu)

K1GQ (FN43in98)

K5ND (EM12kv)

K7GQ (DM09cm)

Kenai Alaska (BP40ln)

KH6CW (BK29ao)

MØBDB (JO01im)

TF4M (HP85fp)

Tokyo Japan (PM95vp22)

VK2NP (QF56ma)

VK6NC (OF78xc)

W2CS (FN32el23)

W4CB (FM06du32)

WA1Z (FN42it36)

WD7K (DN08wl72)

WRTC 2018 (JO61kt55)