points within a particular distance

Question

I have a table conatining a set of points. I would like to make a query that checks the distance between the points and if the distance is small er than the tolerance it would set the points to just one.

Any suggestions how I can accomplish such task?

The following is a graphical issue of what I have. Now I want that only one point will exist where three distinct roads meet

enter image description here

[What have you tried?](http://mattgemmell.com/2008/12/08/what-have-you-tried/) — vyegorov, Feb 18 '13 at 17:58
So you are trying to remove points that are approximately duplicates? — Tim Child, Feb 18 '13 at 23:47
@Tim Child I have edited the question to understand better my concerns — IT_info, Feb 19 '13 at 09:10
More specifically do you want to chose one the points as canonical or an average of them? — Tim Child, Mar 07 '13 at 15:05

score 1 · Answer 1 · answered Feb 18 '13 at 21:50

This is a tricky issue with more than one way to fix it.

One obvious strategy is to try and find unique points snapped to a virtual grid, using ST_SnapToGrid. This technique works best with projected units (e.g., metres with UTM), but not as good with geographic coordinates (with degrees of latitude/longitude), which have variable physical distances.

score 0 · Answer 2 · answered Feb 18 '13 at 20:23

0

If I understandd you right:

1)Read about ST_Distance

2)Write your own function, wich will use ST_Distance and maybe one of theese algorythms(a little simplified for your task)

answered Feb 18 '13 at 20:23

Skiv_mag

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points within a particular distance

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