Plate.gmt problem

[jhtong33]

Hello,
I want to re-plot the plate.gmt to compare with Bird, (2003)
But I found that there is a line on the map (180,90) to (180,-90)
I don't know why dose this line plot in my map.

there is my gmt6 script

gmt begin GlobalPlate png,pdf
gmt coast -JH180/12c -Rg -B0 -W0.2p,100 -A10000
gmt basemap -BWSne+t"Global Plate"
gmt plot plates.gmt -W0.3p,red
gmt plot PB2002_plates.dig.txt -W0.3p,blue 
gmt end show

thanks!

[mrbryce]

this looks like a bounding box such as ne_10m_wgs84_bounding_box