Hi Saranya,
2017-02-20 5:57 GMT+01:00 Saranya Kuniyil :
>
>> Hi all,
>> I am new to postgis and I need to find intersection of three polygons.
>> In my table named "mytable" contains large no of polygon coordinates and
>> grouped into three categories by adding a field called "filename".I
>> label
Thanks Paul, I get it now.
So I guess, it all comes from the fact that an arc is defined as the
shortest path between 2 points which in the geometry case is a straight
line and in the geography case is a great circle.
This also mean that "the polygon I had in mind" cannot be defined as a
geography
:) :) :)
Your second polygon has the same problem as the first, except in reverse...
Your second polygon basically covers no area at all, since it consists of
two arcs that both do a direct southerly run to the south pole.
P.
On Sun, Feb 19, 2017 at 8:09 PM, Sebastien Delaux
wrote:
> Thanks f
For example:
POLYGON((0 0,0 1,1 1,1 0,0 0)) filename as part1
POLYGON((0 0,0 3,3 3,3 0,0 0)) filename as part1
POLYGON((0 0,0 2,2 2,2 0,0 0)) filename as part2
POLYGON((0 0,0 5,5 5,5 0,0 0)) filename as part2
POLYGON((0 0,0 3,3 3,3 0,0 0)) filename as part3
POLYGON((0 0,0 4,4 4,4 0,0 0))
Hey,
sorry to say it's very difficult to understand what you want to do.
Please either do a schema or a precise description (with math: you have
setA, set B, setC , and you want to find ...).
Cheers,
Rémi-C
2017-02-20 5:57 GMT+01:00 Saranya Kuniyil :
> Hi all,
> I am new to postgis and I need to
