No way unless you know the varieties. Both snap and shelling peas vary in pod size and also in plant size. Of course if the pods are formed its easy. Snap peas are tender and snap when you break them, shell peas have tough stringy pods.

I draw a map of the garden at planting time in case tags go missing.

Thanks, Farmerdill - when the pods form I'll do that!
Happyday, that certainly would have solved the problem. I'll try and be more organized next year (but then I say that EVERY year...)
Judith