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I need to draw a line between two points and create a buffer around this line. The only difficulty is that I need to draw not a "cartesian" line but a line that is laying on the spheroid.

I tried to use ST_MakeLine but it has only geometry parameters so it draws only a straight line, not a curve (which is a straight line on spheroid).

Unfortunately ST_LineFromText also does the same.

Here is an example from http://postgis.net/workshops/postgis-intro/geography.html.

I want to draw the red curve. (Btw the length of this curve can be calculated by the ST_Distance(geography, geography))

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The later versions of PostGIS have ST_Segmentize(geography) that will densify a line in geographic space. Start with a two-point line (start, end) and densify it. Now run a ST_Buffer(geography, radius) on that line. For really long lines you still might have imperfect results, as ST_Buffer(geography) just wraps a transform to planar space, but you will get a result at least.

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