Evaluation relationships between geometries ( Spatialite examples)

◎within(geom1,geom2) :if the first geometry is completely contained into the second one.
                                        :第一個圖形完全的包含在第二個圖型內


example 1-within(points ,polygon):

SELECT a.* FROM test4326point as a
join on_areas as b
where overlaps(a.geometry,b.geometry)


I test the line , point and polygon ,I got it must all in the next polygon ,or the border on the next polygon,Only that on others !!


◎Intersects:if the intersection of both geometries is not empty
                  :如果兩個圖型交集處不為空

→intersects(lines,polygon)   :: Be applicable point ,polygon

     If the line touched a little border ,It's true,I got if the line have any touched or touched on the border side , It's true ,No any doubt.



◎Contains: if the second geometry id completely contained into the first one
                 : 第二個圖型完整的包覆第一個圖(意思是下面的範例polygon2必須要筆polygon1大,並且還要必須完全包覆它,也可以說是within()的opposite)

→Contains(polygon1,polygon2) :: This function can's used point and linestring.

This function like within() 's opposite,The next geometry must completely contained first geometry!!