I think that the archaeologists are interpreting this mural incorrectly. It appears to me to be a highly stylized representation of the constellations in the sky. I see Scorpio, Cancer, and Gemini, and figures that could be Orion and the Pleiades; more scrutiny would probably reveal the entire night sky.
That makes sense, a bit. I couldn’t make out a map to Easter Island or instructions on reed boat construction in it.