How it used to be done

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Bernard Burton

Sep 19, 2021, 6:58:43 PMSep 19
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

out simultaneously.

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.

Bernard Burton
Weather data and satellite images at:


Sep 20, 2021, 2:27:23 AMSep 20
Wow, that is impressive. We only had to know which stations reported in
m/s (double the number was good enough). I like the fact that the
temperatures were 'corrected' not converted. Will we be going back to
that procedure, I wonder? The only thing of note I remember from my time
at Heathrow was that one assistant managed to plot the whole ob inside a
station circle (Eumed chart only as the station circles were just about
big enough). It was the only one plot though!
I wonder what happened to him subsequently....
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