like GeospatialGeometry but not partial, eg no empty geometries, also only works in a single dimention, eg PostgisGeometry PointXY can't work with PostgisGeometry PointXYZ. so PointXY indicates a 2 dimension space, and PointXYZ a three dimension space.

checks if the first point is the last, and if not so makes it so. this is required for inserting into the database

unwrap postgis geometry so you can for example return it from an API

Returns TRUE if geometry A contains geometry B. https://postgis.net/docs/ST_Contains.html

Returns true if two geometries intersect. Geometries intersect if they have any point in common. https://postgis.net/docs/ST_Intersects.html

allows union of geometries, eg group a bunch together, for example:

 mCombined <- selectOne $ do
   grid <- from $ table Grid
   pure $ st_union $ grid ^. GridGeom


 select $  do
   unit <- from $ table Unit
   forM_ mCombined $ combined ->
     where_ $ (unit ^. UnitGeom) st_intersects (val $ unValue combined)
   pure unit

(GeoPositionWithoutCRS is a catch all for indeterminate CRSs and for expression of positions before a CRS has been determined