[postgis-users] Intersection between circles

Yves Moisan yves.moisan at boreal-is.com
Wed Aug 12 07:33:28 PDT 2009

Hi All,

We would like to split a polygon knowing distances from points a and b
(polygon vertices), sth like from

a------------- d
|              |
|              |
|              |
|              |


a------------- d
| \            |
|   \          |
|    c         |
|  /           |

So from adbea to (acba + adebca)

I know the distances from both a and b and I need to draw segments bc
and ac, so I need to find the intesection of the two circles centered at
a and b with the known radii I have.  Is there a function that would
return the two intersection points of the circles and preferably only
the one contained in my polygon ?

Thanx for pointers.


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