The following documentation comment has been logged on the website: Page: https://www.postgresql.org/docs/16/datatype-geometric.html Description:
Hi, I am writing to suggest a couple of clarifications to "8.8. Geometric Types" documentation chapter. 1. Documentation does not specify what precision is used when persisting point coordinates. There are hints that it's 8 bytes per coordinate, but neither can be taken for sure. Table "8.20. Geometric Types" says that a point takes 16 bytes, which strongly suggests it's 8 bytes per coordinate, but on the other hand, it could be less if a point definition also includes some unspecified metadata. Section "8.8.1. Points" says "Values of type point are specified […] where x and y are the respective coordinates, as floating-point numbers.", however it is unclear what exact type of floating-point numbers is meant. My suggestion is to clearly describe which floating-point datatype is used for point coordinates. 2. Documentation only partly clarifies what are the benefits of using polygon datatype instead of path datatype. Section "8.8.6. Polygons" says that "the essential difference is that a polygon is considered to include the area within it, while a path is not", which clarifies that they are meant to serve different purposes, but nothing more. Table "8.20. Geometric Types" says that a polygon with n vertices takes 24 bytes more than a path with n vertices, but that's all. Only chapter "9.11. Geometric Functions and Operators" really helps in understanding that some functions and operators are available to polygons but not to paths. My suggestion is to: a) point out that different operations can be performed on polygons and closed paths b) clarify what information is stored with a polygon that is not stored with a closed path (these 24 bytes) c) if there are some operations that perform better on polygons than on closed paths, clarify that as well
