Can the help shp file be automatically recognized as a road or river

[LiYuanYuan]

gis related：

I now have vector data in shp format. I have read the shp file through unity and obtained the coordinate information of the surface data
1: But there are too many nodes in it, which makes it impossible to generate rivers normally. Is there any solution;
2: And I found that if the nodes are too dense, there will be no rivers or roads. What is the cause.
3: Must the method createNewNode() be used to create the spline, and can the corresponding nodes be directly identified through the surface data or line data

The above figure shows that longitude and latitude are read;

This is a GeNa node identified and created based on line data, with very high density；

This is the outline of a river. The river expansion here does not work. Generally, the river is generated on both sides of the line. My idea is whether to generate a river according to the inner part enclosed by this line；