How to combine -N and -M options in coast

Q&A
1

I like to have country boundaries in external ascii file
Gives strange Turkey boundaries
gmt begin map png
gmt coast -RTR -JM6i -I9/0/0/255 -I1/0/0/255 -I2/0/0/255 -N1 >turcoast.data
gmt end show
Show error
gmt begin map png
gmt coast -RTR -JM6i -I9/0/0/255 -I1/0/0/255 -I2/0/0/255 -N1 -M >turcoast.data
gmt end show
works file
gmt begin map png
gmt coast -RTR -JM6i -I9/0/0/255 -I1/0/0/255 -I2/0/0/255 -M >turcoast.data
gmt end show

2

When you use -M you dont do any plotting. So there’s no point in giving projection etc (https://docs.generic-mapping-tools.org/latest/coast.html#m).

Also (from manual):

Specify one of -E, -I, -N or -W

Maybe you could try:

gmt coast -RTR -I9 -M > I9_rivers.data
gmt coast -RTR -I1 -M > I1_rivers.data
gmt coast -RTR -I2 -M > I2_rivers.data
gmt coast -RTR -N1 -M > N1_national.data

You’re doing modern mode (gmt begin…gmt end), which is good, but it’s a bit unecessary in this context since you’re just doing simple one-liners.

3

Thanks . It works fine