Origins of the Compass Rose

Image of Compass Rose

The compass rose has appeared on charts and maps since the 1300's when the portolan charts first made their appearance. The term "rose" comes from the figure's compass points resembling the petals of the well-known flower.

Originally, this device was used to indicate the directions of the winds (and it was then known as a wind rose), but the 32 points of the compass rose come from the directions of the eight major winds, the eight half-winds and the sixteen quarter-winds.

In the Middle Ages, the names of the winds were commonly known throughout the Mediterranean countries as tramontana (N), greco (NE), levante (E), siroco (SE), ostro (S), libeccio (SW), ponente (W) and maestro (NW). On portolan charts you can see the initials of these winds labeled around the edge as T, G, L, S, O, L, P, and M.

The 32 points are therefore simple bisections of the directions of the four winds (but the Chinese divided the compass into 12 major directions based on the signs of the Zodiac). For western apprentice seamen, one of the first things they had to know were the names of the points. Naming them all off perfectly was known as "boxing the compass".

There is no absolute standard for drafting a compass rose, and each school of cartographers seems to have developed their own. In the earliest charts, north is indicated by a spearhead above the letter T (for tramontana). This symbol evolved into a fleur-de-lys around the time of Columbus, and was first seen on Portuguese maps. Also in the 14th century, the L (for levante) on the east side of the rose was replaced with a cross, indicating the direction to Paradise (long thought to be in the east), or at least to where Christ was born (in the Levant).

The colors on the figure are supposedly the result of the need for graphic clarity rather than a mere cartographical whim. On a rolling ship at night by the light of a flickering lamp, these figures had to be clearly visible. Therefore the eight principle points of the compass are usually shown on the compass rose in black which stands out easily. Against this background, the points representing the half-winds are typically colored in blue or green and since the quarter-wind points are the smallest, they are usually colored red.

References:

Cartographical Innovations:  an International Handbook of Mapping Terms to 1900 ed. by Helen M. Wallis and Arthur H. Robinson. - Tring, Herts: Map Collector Publications in association with International Cartographic Association, 1987. - ISBN 0-906430-04-6. (This was really quite good, and full of interesting history and details about maps - Bill)

Mapping by David Greenhood. - The University of Chicago Press, 1964. ISBN 0-226-30696-8

More on Compass Roses:

The Famous Brick Pavement Compass Rose of Leonardtown, MD
"http://www.gisnet.com/notebook/CompassRoseMore/"
This 50-foot diameter outdoor compass rose is made entirely of colored bricks and can be seen in the park at the Leonardtown, MD town wharf.
Chart Compasses
http://www.ruf.rice.edu/~feegi/compass.html
More Compass Roses from Portuguese Nautical Charts (images)
http://www.ruf.rice.edu/~feegi/rose.html

Links to Historical Maps:

History of Cartography
http://www.geography.wisc.edu/histcart/
Oddens' Bookmarks
http://oddens.geog.uu.nl/index.html

Nautical History:

Wooden Boats - Not Just A Hippie Dream *** New! ***
http://theweatherguage.blogspot.com/
If you love the elegance and gracefullness of a wooden sailboat gliding silently through the water, but would like to know more about the craftsmanship that goes into them, check out "The Weather Gauge" and the step by step process of restoring a Friendship sloop named Désirée, back to her orignal beauty.
Why The Moonraker Is The Tallest Sail
http://www.gisnet.com/notebook/great_sails.php

The 32 Points of the Compass

PointDirectionAzimuth
0 North 0° - 0'
1 N by E 11° - 15'
2 NNE 22° - 30'
3 NE by N 33° - 45'
4 NE 45° - 0'
5 NE by E 56° - 15'
6 ENE 67° - 30'
7 E by N 78° - 45'
8 East 90° - 0'
9 E by S 101° - 15'
10 ESE 112° - 30'
11 SE by E 123° - 45'
12 SE 135° - 0'
13 SE by S 146° - 15'
14 SSE 157° - 30'
15 S by E 168° - 45'
PointDirectionAzimuth
16 South 180° - 0'
17 S by W 191° - 15'
18 SSW 202° - 30'
19 SW by S 213° - 45'
20 SW 225° - 0'
21 SW by W 236° - 15'
22 WSW 247° - 30'
23 W by S 258° - 45'
24 West 270° - 0'
25 W by N 281° - 15'
26 WNW 292° - 30'
27 NW by W 303° - 45'
28 NW 315° - 0'
29 NW by N 326° - 15'
30 NNW 337° - 30'
31 N by W 348° - 45'

URL: http://www.gisnet.com/notebook/comprose.php -- Last updated: Feb 2001
© 1999-2001 by Bill Thoen
<bthoen@gisnet.com>

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