svg marker
<svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg">
<defs>
<!-- simple dot marker definition -->
<marker id="dot" viewBox="0 0 10 10" refX="5" refY="5"
markerWidth="5" markerHeight="5">
<circle cx="5" cy="5" r="5" fill="red"/>
</marker>
</defs>
<!-- Data line with polymarkers -->
<polyline points="15,80 29,50 43,60 57,30 71,40 85,15" fill="none" stroke="grey"
marker-start="url(#dot)" marker-mid="url(#dot)" marker-end="url(#dot)"/>
<!--
Marker attributes:
markerHeight - the height of the marker viewport, default value: 3
markerWidth - the width of the marker viewport, default value: 3
markerUnits - the coordinate system for the marker content and the attributes markerWidth and markerHeight
possible values: userSpaceOnUse or strokeWidth,
default value: strokeWidth
orient - the orientation of the marker relative to the shape it is attached to
possible values: auto, auto-start-reverse, or <angle>;
default value: 0
preserveAspectRatio - defines how the svg fragment must be deformed if it is embedded in a container with a different aspect ratio,
value format: "(none|xMinYMin|xMidYMin|xMaxYMin|xMinYMid|xMidYMid|xMaxYMid|xMinYMax|xMidYMax|xMaxYMax) (meet|slice)?",
default value: xMidYMid meet
refX - the x coordinate for the reference point of the marker,
possible values: left, center, right, or <coordinate>;
default value: 0
refY - the y coordinate for the reference point of the marker,
possible values: top, center, bottom, or <coordinate>;
default value: 0
viewBox - defines the bound of the SVG viewport for the current SVG fragment,
default value: none
-->
</svg>