Hace años utilicé una herramienta que le metías la imagen, seleccionabas de modo gráfico el area y le añadías el link (el js en tu caso, o lo que sea). Te salía el html con todo el código ya hecho. Lo malo es que no me acuerdo qué programa era, pero sí que tengo aún el código de salida, por si te sirve de algo xD
<div>
<map id="mapa" name="mapa">
<area shape="poly" alt="Asturias" coords="157,27,163,44,175,41,189,41,197,37,206,36,203,30,192,30,183,27,173,29" href="http://www.princast.es" title="Asturias" />
<area shape="poly" alt="Cantabria" coords="213,36,229,45,230,39,241,34" href="http://www.cantabria.com" title="Cantabria" />
<area shape="poly" alt="País Vasco" coords="251,35,258,35,272,39,269,47,267,56,252,49,256,42" href="http://www.euskadi.net" title="País Vasco" />
<area shape="poly" alt="La Rioja" coords="254,61,255,70,278,72,278,66" href="http://www.larioja.org" title="La Rioja" />
<area shape="poly" alt="Navarra" coords="279,47,289,40,297,46,288,72,284,59" href="http://www.cfnavarra.es/" title="Navarra" />
<area shape="poly" alt="Arag n" coords="307,47,341,49,342,67,335,80,332,106,323,113,311,130,287,125,297,112,292,101,280,94,287,75,296,74" href="http://www.aragon.es" title="Aragón" />
<area shape="poly" alt="Cataluña" coords="348,49,351,66,341,84,341,111,345,116,354,98,380,90,400,74,394,53,385,58,363,56" href="http://www.gencat.net/" title="Cataluña" />
<area shape="poly" alt="Galicia" coords="111,42,118,55,118,67,127,71,130,74,137,75,150,75,160,67,152,58,155,44,150,29,142,22" href="http://www.xunta.es/" title="Galicia" />
<area shape="poly" alt="Castilla y Le n" coords="163,56,172,48,202,46,225,53,242,53,247,68,255,77,279,79,271,96,248,91,222,111,213,123,199,128,171,120,167,120,162,104,176,91,176,86,165,72" href="http://www.jcyl.es/" title="Castilla y León" />
<area shape="poly" alt="Madrid" coords="226,122,226,117,233,116,238,110,240,116,248,126,240,131" href="http://www.munimadrid.es" title="Madrid" />
<area shape="poly" alt="Extremadura" coords="161,130,160,144,150,149,154,166,156,186,168,194,174,196,189,189,202,172,209,160,200,153,192,130" href="http://www.juntaex.es/" title="Extremadura" />
<area shape="poly" alt="Castilla La Mancha" coords="213,174,225,184,267,178,277,191,288,182,292,182,298,173,301,173,296,157,291,147,295,134,281,133,279,117,287,112,277,102,251,102,246,109,255,116,255,131,239,140,220,132,205,135,210,151,219,153" href="http://www.jccm.es/" title="Castilla La Mancha" />
<area shape="poly" alt="Andalucía" coords="147,208,148,222,162,225,180,249,191,243,200,250,226,239,269,239,275,232,279,235,289,223,274,203,267,199,264,188,226,194,207,181,201,186,198,198,175,202,161,202" href="http://www.andalucia.org/" title="Andalucía" />
<area shape="poly" alt="Murcia" coords="283,197,296,214,307,212,312,205,307,200,304,183" href="http://www.carm.es/" title="Murcia" />
<area shape="poly" alt="Valencia" coords="315,193,332,178,321,163,321,151,336,119,329,118,321,133,306,139,301,151,307,158" href="http://www.valencia.es/" title="Valencia" />
<area shape="poly" alt="Islas Baleares" coords="356,159,350,169,357,180,365,181,434,138,412,121,375,136,349,167" href="http://www.caib.es/" title="Islas Baleares" />
<area shape="poly" alt="Islas Canarias" coords="92,329,111,323,118,295,106,295,18,309,13,339" href="http://www.gobcan.es/" title="Islas Canarias" />
<area shape="poly" alt="Ceuta" coords="190,275,191,284,197,283" href="http://www.ciceuta.es/" title="Ceuta" />
<area shape="poly" alt="Melilla" coords="264,288,258,293,263,301,267,301" href="http://www.melilla.es/" title="Melilla" />
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