A scatter plot of the PL xG data with axes and a button.

Help from: https://d3-graph-gallery.com/graph/line_select.html and https://www.w3schools.com/howto/howto_js_dropdown.asp and https://www.freecodecamp.org/news/how-to-build-a-dropdown-menu-with-javascript/ and https://alvarotrigo.com/blog/drop-down-menu-javascript/ and https://www.solodev.com/blog/web-design/how-to-add-scroll-functionality-to-your-dropdowns.stml and https://www.youtube.com/watch?v=POeKjbV6TMI and https://www.w3schools.com/js/js_events.asp and https://www.sololearn.com/Discuss/422441/how-to-use-image-as-a-button-in-java-script and https://www.d3indepth.com/selections/