There are different symbols on monero full list node map (https://monerohash.com/nodes-distribution.html) What are the differences between these symbols: yellow circle green circle blue reverse drop
A blue reverse drop indicates the approximate location of the node as per geolocation of the IP address. A green circle indicates that the approximate location of more than 1, but less than 10 nodes is the same. A yellow circle indicates that the approximate location of more than 10 nodes is the same. For both the green and yellow circle it probably means that multiple people are hosting a node on a VPS hosting provider that is located there.