1REM		GMT EXAMPLE 13
2REM
3REM Purpose:	Illustrate vectors and contouring
4REM GMT modules:	set, grdmath, grdcontour, grdvector, subplot
5REM DOS calls:	del
6REM
7gmt begin ex13
8	gmt set FONT_HEADING 40p,Times-Italic
9	gmt grdmath -R-2/2/-2/2 -I0.1 X Y R2 NEG EXP X MUL = z.nc
10	gmt grdmath z.nc DDX = dzdx.nc
11	gmt grdmath z.nc DDY = dzdy.nc
12	gmt subplot begin 2x2 -M0.1c -Ff15c -BWSne -T"z(x,y) = x@~\327@~exp(-x@+2@+-y@+2@+)"
13		gmt grdcontour z.nc -C0.05 -A0.1 -Gd5c -S4 -T+d8p/2p -c0,0
14		gmt grdcontour z.nc -C0.05 -Gd5c -S4 -c0,1
15		gmt grdvector dzdx.nc dzdy.nc -I0.2 -Q0.25c+e+n0.25i+h0.5 -Gblack -W1p -S12c
16		gmt grdcontour dzdx.nc -C0.10 -A0.5 -Gd5c -S4 -T+d8p/2p -c1,0
17		gmt grdcontour dzdy.nc -C0.05 -A0.2 -Gd5c -S4 -T+d8p/2p -c1,1
18	gmt subplot end
19gmt end show
20del z.nc dzdx.nc dzdy.nc
21