diff --git a/gmtsph-JA.sh b/gmtsph-JA.sh
index db1c4ec..835eafa 100755
--- a/gmtsph-JA.sh
+++ b/gmtsph-JA.sh
@@ -15,14 +15,15 @@ plotgrad=0
 plotsun=0
 clon=("0/0/115" "180/0/115")
 polyfile='null'
+bartick="a" #色标轴标轴间隔 a表示自动
 # 从命令行获取参数
-while getopts "hi:r:u:c:a:G:l:p:gs" arg
+while getopts "hi:r:u:c:a:v:G:l:p:gs" arg
 do
 	case $arg in
 		h)
 			printf "simple global wide data mapping using GMT script. The template accepts a grid (.nc .grid) file as input and outputs a .png and a .eps file. \
 For futher explanations, please look for GMT's manuscripts.\nAuthor: Yi Zhang (zhangyi.cugwuhan@gmail.com)\n" 
-			printf "usage: ${0##*/} -i<grid-data> [-r<xmin>/<xmax>/<ymin>/<ymax>] [-l<clon>/<clat>/<horizon>] [-u<unit>] [-c<cpt-file>] [-a<x-label>,<y-label>] [-g] [-s] [-G<grad-data>] [-p<polygon-file>]\n"
+			printf "usage: ${0##*/} -i<grid-data> [-r<xmin>/<xmax>/<ymin>/<ymax>] [-l<clon>/<clat>/<horizon>] [-u<unit>] [-c<cpt-file>] [-a<x-label>,<y-label>] [-v<c-tick>] [-g] [-s] [-G<grad-data>] [-p<polygon-file>]\n"
 			printf "%s\t%s\n" "-i" "input grid file"
 			printf "%s\t%s\n" "-r" "data range. The template will ditect the input data range automaticly, the use of this option will overwrite the range."
 			printf "%s\t%s\n" "-l" "central longitude and latitude values of the plot, the default value is 0/0/115,180/0/115. "
@@ -30,6 +31,7 @@ For futher explanations, please look for GMT's manuscripts.\nAuthor: Yi Zhang (z
 			printf "%s\t%s\n" "-c" "color cpt. The default is rainbow."
 			printf "%s\t%s\n" "-s" "plot the day-night terminator. The default is false."
 			printf "%s\t%s\n" "-a" "axis labels. The deafults are x (m) and y (m)."
+			printf "%s\t%s\n" "-v" "intervals of color bar's labels. the script will set the intervals automatically if -v option is not set."
 			printf "%s\t%s\n" "-g" "use grdgradient. The default is false."
 			printf "%s\t%s\n" "-G" "provide a different input grid data for the use of grdgradient. This should be used with the '-g' option at the same time"
 			printf "%s\t%s\n" "-p" "plot polygons via a file."
@@ -49,6 +51,8 @@ For futher explanations, please look for GMT's manuscripts.\nAuthor: Yi Zhang (z
 			clon=(${OPTARG//,/ });;
 		a)
 			labels=(${OPTARG//,/ });;
+		v)
+			bartick=$OPTARG;;
 		g)
 			plotgrad=1;;
 		G)
@@ -119,9 +123,9 @@ else
 	#-C${cptfile}+Uk 使用km（色标单位除1000
 	#如果unit等于km则在cptfile后面添加+Uk
 	if [[ ${unit} == 'km+Uk' ]]; then
-		gmt psscale -I -Dx0.85i/-0.2i+w1.5i/0.05i+h -C${cptfile}+Uk -Bxa -By+l"km" -X-1.7i -O >> $psfile
+		gmt psscale -I -Dx0.85i/-0.2i+w1.5i/0.05i+h -C${cptfile}+Uk -Bx${bartick} -By+l"km" -X-1.7i -O >> $psfile
 	else
-		gmt psscale -I -Dx0.85i/-0.2i+w1.5i/0.05i+h -C${cptfile} -Bxa -By+l${unit} -X-1.7i -O >> $psfile
+		gmt psscale -I -Dx0.85i/-0.2i+w1.5i/0.05i+h -C${cptfile} -Bx${bartick} -By+l${unit} -X-1.7i -O >> $psfile
 	fi
 	gmt psconvert $psfile -A -TEG -E300
 	# 删除临时文件 使用linux终端rm命令