Q: When I did geometry buffer analysis, I filled in a small value 500, why the result is the entire map?

A: Because the analysis object unit is consistent with the coordinate system of the map. E.g. If the coordinate system is WGS1984, then the analysis radius is 500 degrees, so the result is the entire map. The solution is that you could use the client software to transform the map into coordinate system with meter unit. In the future, iServer 7C and later versions will support giving SRID projection information when you do geometry buffer analysis, so that you will not need to transform the coordinate system.