[RESOLVED] locating position in a grid

I am looking for some help or code for the following (it must have been done many times before but I don't quite know how to word a search):

I have a series of values with x,y coordinates;
23,5
31,19
47,7
etc
and a grid which is from 20-50 in steps of 10 along x and 0-20 in steps of 2 along y.
I want to find which cell each point is in (and the center of that cell).
Eg the first point falls in cell x1, y3 with center at x=25, y=5
Any help or suggestions where to look would be greatly appreciated
Thanks

This seems to be working. About the mathematical calculation: i'm not sure if it is efficient enough, maybe it's possible to do the same with simpler calculations or applying some given formula, but anyways, this is what i've came to..
Add a CommandButton and this code to your Form. For testing change the values where it says "Example", now it's x=23,y=5.

Code:

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Private Type TypeCoordAxis
    xFrom  As Single
    xTo    As Single
    xStep  As Single
    yFrom  As Single
    yTo    As Single
    yStep  As Single
End Type

Private Type TypePoint
    x  As Single
    y  As Single
End Type

Private Sub Command1_Click()
Dim udtAxis As TypeCoordAxis, udtPoint As TypePoint
Dim lCell As TypePoint, lCellCenter As TypePoint

    'Set Axis for X
    udtAxis.xFrom = 20
    udtAxis.xTo = 50
    udtAxis.xStep = 10
   
    'Set Axis for Y
    udtAxis.yFrom = 0
    udtAxis.yTo = 20
    udtAxis.yStep = 2
   
    'Example
    udtPoint.x = 23
    udtPoint.y = 5
   
    GetCellAndCenter udtAxis, udtPoint, lCell, lCellCenter
   
    MsgBox "CELL NUMBER: (" & lCell.x & ", " & lCell.y & ")"
    MsgBox "CELL CENTER: (" & lCellCenter.x & ", " & lCellCenter.y & ")"
   
End Sub

Private Sub GetCellAndCenter(pAxis As TypeCoordAxis, pPoint As TypePoint, _
                            pCell As TypePoint, pCellCenter As TypePoint)
Dim xUnits As Long, yUnits As Long
Dim xRange As Single, yRange As Single

    xRange = pAxis.xTo - pAxis.xFrom
    yRange = pAxis.yTo - pAxis.yFrom
   
    xUnits = xRange / pAxis.xStep
    yUnits = yRange / pAxis.yStep
   
    pCell.x = Fix((pPoint.x - pAxis.xFrom) / xRange * xUnits + 1)
    pCell.y = Fix((pPoint.y - pAxis.yFrom) / yRange * yUnits + 1)
   
    pCellCenter.x = pAxis.xFrom + pCell.x * pAxis.xStep - pAxis.xStep / 2
    pCellCenter.y = pAxis.yFrom + pCell.y * pAxis.yStep - pAxis.yStep / 2
   
End Sub

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Thanks a lot jcis - works brilliantly. I don't realy understand how it works but, hey, it works! Even works when the point lies out side the given limits of x and y.
Thanks again

You're welcome, and welcome to the Forums. If your problem is resolved remember to "Mark Thread Resolved" you'll find this option in menu "Thread Tools"