Calculate how far a line travels through each square in a grid created using the meshm function

Hi, I have plotted a grid using the meshm function over a map with earthquakes and seismic stations plotted. Between each earthquake and each seismic station which recorded it is a travel path (a line).

I want to determine how far each travel path crosses through each square in the grid created using meshm.

The data I have is the earthquake latitude, earthquake longitude, station latitude and station longitude, and the lines were drawn simply using plotm, so I'm aware I'll have to determine the y = mx + c form of each line.

If anyone could help, or at least provide some pointers that would be much appreciated.

Thanks

[Rik]

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