Finding Closest Point RSS

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  glog

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  Finding Closest Point

  Mar 24, 2004 08:22 PM|LINK

  I have a list of x,y points in a DB, and I want a user to be able to click anywhere on an image button, and get back a value of the closest point. Anything built into GDI+ that may help me out with this? Thanks guys. -glog-
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  Atrax

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  Re: Finding Closest Point

  Apr 02, 2004 08:23 AM|LINK

  I don't think GDI is what you should be using here. sutely it's just a SQL issue? if you click an input type="image" /> you get the x, y passed to the next page - plug these coords into a SQL statement with some math and you can get the rows back in order of proximity. I'll see if I can work up a SQL trick for this. can't recall off the top of my head how it's done.
  RTFM - straight talk for web developers. Unmoderated, uncensored, occasionally unreadable
  
  Jason Brown - MVP, IIS
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  Jigar

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  How to find distance.

  Apr 02, 2004 01:21 PM|LINK

  This function will find Distance between two points..

  public double Distance(System.Drawing.Point p1,System.Drawing.Point p2){
        double dx = p1.x - p2.x;
        double dy = p1.y - p2.y;
        return Math.Sqrt((dx * dx) + (dy * dy));
  }
  
  
  
  
    And this is how its works.
  
  
                          * p2
                        / |
                      /   |
                     /    | dy
                   /      |
                 /        |
               /          |
             *---------#
            p1   dx
  
  
  distance = SquareRoot((dx x dx) + (dy x dy))

  Jigar Desai
  -----------------------
  Do not forget to "Mark as Answer" on the post that helped you.
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  Atrax

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  3733 Posts

  Re: How to find distance.

  Apr 03, 2004 12:41 PM|LINK

  cheers for filling that in, but I'm still sceptical that this is a GDI issue, myself. note the 'DB' reference.
  RTFM - straight talk for web developers. Unmoderated, uncensored, occasionally unreadable
  
  Jason Brown - MVP, IIS
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  Jigar

  Contributor

  4629 Points

  935 Posts

  Find Closest point using DB

  Apr 03, 2004 04:51 PM|LINK

  Yes you can do same in DB check out this sample SQL Script. run into SQLServer Query Anlyser. I have used TempTable just to show how it works.

  Declare @Px int
  Declare @Py int
  
  
  Set @Px = 1
  Set @Py = 1
  
  
  CREATE TABLE #TemporaryTable (ItemID int ,X int,Y int)
  INSERT INTO #TemporaryTable Values(1,-2,2)
  INSERT INTO #TemporaryTable Values(2,2,2)
  INSERT INTO #TemporaryTable Values(3,2,-2)
  INSERT INTO #TemporaryTable Values(4,-2,-2)
  
  
  Select * , SQRT((@Px - X) * (@Px - X) + (@Py - Y) * (@Py - Y)) AS Distance
  From #TemporaryTable
  DROP TABLE #TemporaryTable

  Out put Is...

  ItemID X      Y      Distance                                              
  ------ ------ ------ ------------------
  1        -2      2      3.1622776601683795
  2         2      2      1.4142135623730951
  3         2      -2     3.1622776601683795
  4        -2     -2     4.2426406871192848
  

  You can create StoredProcedure using this logic to return closest point .
  Jigar Desai
  -----------------------
  Do not forget to "Mark as Answer" on the post that helped you.