Here, two styles (Style) are used in order to combine symbols.
For the first style, define a fill color (Fill Color), plus a color (Outline color) and a line width (Width) for the stroke.
For the second style there’s no fill color, only a stroke color and -width (Outline color and Width). In addition, the line style of the stroke is set as dashed (Pattern) with an interval of 10 pixels filled and 10 pixels spacing.
Example, in map