In class exercises

Part I - Slides

Part II - Boundless Tutorial

1. 21-22

Part III - Validate

SELECT iso, name, ST_IsValid(geom), ST_IsValidReason(geom)
FROM copper.countries_bndy
WHERE NOT ST_IsValid(geom);

UPDATE copper.countries_bndy
SET geom = ST_MakeValid(geom)
WHERE NOT ST_IsValid(geom);