The linestrings wouldn't need to be continuous as long as you attribute
them left and right bank. Then your query would be to find the shortest
distance between two linear datasets (left and right banks). A cross
product query would help you here. Or, ST_Collect your banks into two
multilinestrings, one for left and one for right bank. Then compute the
distance between them.
But you are still going to have problems at the head and mouth of the
river. There, the left and right banks touch, so the minimum distance
between the left side of the river and right side of the river is zero.
-- Kevin
Surya Tarigan wrote:
Hallo Nicklas
fortunately I have linestring version of the polygon, but it seems
that the linestirings are not continuous. Does st_distance still
apply? Or are there any postgis function to make the polyline continuous?
kind regards,
------------------------------------------------------------------------
*From:* "[email protected]" <[email protected]>
*To:* PostGIS Users Discussion <[email protected]>
*Sent:* Thursday, October 1, 2009 3:50:37 PM
*Subject:* Re: [postgis-users] polygon minimum width
Hallo
I think the easiest way is to make a linestring of the
polygon.boundary and then cut the line in the start and end so you get
two more or less paralell lines.. Then you can use st_distance to find
the shortest distance between them.
Hope that helps
Nicklas
2009-10-01 Surya Tarigan wrote:
>
>
Dear list,
>
>
I have a river polygon with polygon length about 20 km. How can I
query the minimum width of the river polygon. I tried to search
previous threads, but I could not find any clue.
>
>
kind regards,
>
>
surya
>
------------------------------------------------------------------------
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