Polylines on Google Maps display path between different locations. For your wordpress site you can activate the WP Google Map Pro plugin to display such paths (like the one in map below) between any set of locations using a polyline. The plugin will also enable you to customize the style of polyline, stroke color, stroke weight etc.
This google map wordpress plugin is available on codecanyon to get it.
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We will be glad to discuss any of your needs related to our wordpress plugins . if any of functionality you'd like to see in products, you can reach us by via email firstname.lastname@example.org.