let blueLegend = 'data:image/png;base64,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'
let yellowLegend = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABwAAAAcCAMAAABF0y+mAAAAPFBMVEX/ygD/ywD/0QD/zwD/zwz/0wD/zhH/0AX/0BD/0gf/30//1Sj/0Rn/zxP/zhP/753/52//zhX/75z/+N4AO27MAAAAE3RSTlMBBgoPKBY8GzQhp3ZbT0T11VT1sV/+ZAAAAIxJREFUKM+90tsOgzAIBmDdoNCzzvd/19EmjrAY7vRP775AWuhyf9ZllXNNv1zaa0bV0HtGWU0IkQhR2OowpAiSSDj0zyJwkDDEUxUJuNVSamMgg7OQ255TynvjUWoRQs1b71uuAU7UrqGkfhw9laB9XbRtP9rWvZD/FH8I/vj8wfsr85ftfxONwAP5AvslBuoT2y5YAAAAAElFTkSuQmCC'
