City nodes?

I have googled this and can’t figure it out - how are nodes determined? Why do some streets have no nodes and other streets are completely saturated?

Second question - how do I add a city?? I’ve been trying to add Mendocino,CA (the town not county) for months. I realize it may be unincorporated but how do I add it? Yes I have added it to the google spreadsheet tracker for missing cities.

All streets have at least two nodes, one in each end.
Extra nodes are added if another street are adjoined or curves are added.
So in theory you could have a 10 mile long road with only two nodes.

For the city, it need to have a boundary.

Adding on to Henrik’s response, it’s completely dependent on the OSM user that creates the ‘way’ (ie street) and other OSM users that update the way. There should be sufficient nodes to track any curves, turns and intersections but that can be subjective to each OSM user ie some may think three nodes are good enough to track a curve in a street; another user may think there should be ten nodes.

This looks like Mendocino in OpenStreetMap: Way: ‪Mendocino‬ (‪33167350‬) | OpenStreetMap

This exists as a Way record in OSM, and my code currently only works with Relation records. In past situations like this, someone has created a Relation record based on the Way record (I don’t know how to do this).