Module validate 

Geometry validation (geo_is_valid).

Checks structural validity per OGC Simple Features:

• Polygon rings must be closed (first == last coordinate)
• Polygon rings must have at least 4 points (triangle + close)
• Polygon exterior ring should be counter-clockwise (right-hand rule)
• Polygon holes should be clockwise
• No self-intersection of ring edges
• LineStrings must have at least 2 points

Functions

is_valid

Whether a geometry is valid (no issues).

validate_geometry

Validate a geometry. Returns a list of issues (empty = valid).