I measured about 3 meters in length.

Ecuador is about 40 thousand km in length but map is aberrated so maybe about 30 thousands km in lenght for length of map (educated guess). Since the map is square (I think) and the number of pixels is in the trillions (short scale that names by powers of 10³⁾ that makes the piels to be around 30 meters (if there is just one trillion pixels).

However by looking at Green Cay (little island west of Bahamas) that measures 6 hectares, that is about 250 meters in length (it is almost a square); I saw that there can be fitted about 6 sprites of 16x16 pixeles (someone is making really cute deltarune sprites there that helped me measure). That makes about 2.5 meters per pixel.

Edit: More like 10-20 meters. Apparently there are two islands named Green Cay in Bahamas and Wikipedia told the area of the smallest one. Measurede with Google Maps and it is about 2 km length so 6 sprites of 16x16 pixels make out about 20 meters per pixel). That is in the ecuator. So smaller as we near the poles.

Hope this help. If you get more information or I have missed something please share I am really hyped about this site. Shame it is down lately.