I expect some of the older users of this group will have had experience
plotting synoptic charts (double pens using red and blue liquid ink).
However, in my case , the coded reports were always printed out by
teleprinter, and the 'blank' charts already had numbered stations on the
country background. The attached snippet is from the Met Mag for November
1936, and shows how it could be done by someone with exceptional expertise.
The Plotting of Weather Charts
Meteorologists, professional or amateur, who have constructed
weather maps are familiar with the task involved in plotting data
for a large number of stations.
The data received by wireless usually undergoes three transformations
1. Morse to numerals (this is usually performed by wireless
2. Numerals to plain language.
3. Plain language to symbols on the chart.
With practice it becomes possible to combine transformations 2
and 3, although this entails knowledge of the positions of some 3,000
stations, and the symbols corresponding to some 200 different
code figures. This procedure is normally adopted by meteorologists,
but it must be unusual for all three transformations to be carried
At the Royal Naval College, Dartmouth, synoptic charts are
plotted daily and recently Cadet Satow plotted a chart of northwestern
Europe and the northern Atlantic, combining all three
transformations. The symbols were plotted on the chart direct
from the wireless signals of G.F.A. and F.L.E. (transmitted at
approximately 30 words per minute) and heard in the headphone
without any intermediate writing down of the code groups. The
plotting was done in two colours, and the temperature from all
countries, except the British Isles, was corrected from Centigrade
to Fahrenheit before entry on the chart. The chart was examined
by a Master of the College and no error was detected. It must be
agreed that this involves a very thorough knowledge of the codes,
the positions of stations and mental concentration of a high order.
Weather data and satellite images at: