**One biggest was weather via radio morse code and Sextant at sea.
When the telegraph cam out the found weather tracking for west to east .
Simple basic information was used
Like this format
Later add temperature and cloud or fog
Before radio they would use city code .
After radio was in board ships use a basic format like N35W120
So it brief morse code message.
N35W120 P992 T72/CLR.
This made first maps for forecasting VIA Radio since before 1910
The satalite 
image has saved a lot ship as they could avoid :
: Hurricanes and very bad weather. Ship did not have to in storm to transmit weather data start in mid 1960’s
Maps
1920’s
1944
1990’s
Dave**