title: How to add buffer to a polygon crossing the dateline in PostGIS?
body: <p>I'm trying to add 10km-buffer to a polygon of Russian administrative boundary with PostGIS functions just like below.</p>
  
  <pre><code>SELECT ST_Multi(ST_Buffer(geom::geography, 10000)::geometry)
  FROM example.russian_boundary;
  </code></pre>
  
  <p>However the results looks like this and it is not what I'm expecting:</p>
  
  <p><a href="https://i.stack.imgur.com/euGHa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/euGHa.png" alt="enter image description here"></a></p>
  
  <p>The buffered-polygon should be like this, which is almost the same look as the original one:</p>
  
  <p><a href="https://i.stack.imgur.com/NwrnT.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NwrnT.png" alt="enter image description here"></a></p>
  
  <p>I think this fails because the polygon is crossing the dateline but I haven't found a solution yet.</p>
  
  <p>Anyone know how can I do this?</p>
  
  <p>Thank you.</p>