Find for nearest object?

Anonymous — Thu, 04 Dec 2003 11:11:15 GMT

Hi,
does anyone know an easy way to find the nearest line to a point. The way I have been doing this is creating a selection set of lines and looping thru the lines, checking the distances and if the distance is shorter than the last hold that one. I was kinda looking from a less eloborate way to find this. Thanks

Re: Find for nearest object?

Anonymous — Thu, 04 Dec 2003 11:36:15 GMT

http://www.ping.be/math/recht.htm

Re:

Anonymous — Thu, 04 Dec 2003 11:46:16 GMT

Thanks for reply, but I know how to find the distance between a point and a line. I was just looking for a simpler way to find the closest line to a point.

Re:

Anonymous — Thu, 04 Dec 2003 12:49:08 GMT

Don't know if this helps but...

I did somthing similar but decided that I wanted to
loop through the smallest sset poosible so starting from the point that I
picked, I created a selection set with a crossing window that began one unit
below and to the left and ended one unit to the right and above. If something
was found, check the distance on the entites (unless only one was found). If
nothing was found, add one more unit to each of the points. Keep repeating until
results is found or offset reaches a preset number (a max distance value). Why
am I blabbering?? Here is the code, see if it helps....

Public Function FindNearestEntity(ByVal Point1 As
Variant, ByVal MaxDistance As Double, Optional LayerPattern As String = "*") As
AcadEntity
Dim sst_items As AcadSelectionSet
Dim ent_retrn
As AcadEntity
Dim dbl_offst As Double
Dim pnt_lleft(2) As
Double
Dim pnt_urght(2) As Double
Dim dxf_codes(7) As
Integer
Dim dxf_value(7) As Variant
Dim dbl_prevs As
Double
Dim dbl_distn As Double
Dim pnt_nears As
Variant
Dim ent_check As AcadEntity

dxf_codes(0)
= 8
dxf_value(0) = LayerPattern
dxf_codes(1) = -4

dxf_value(1) = "<OR"
dxf_codes(2) = 0
dxf_value(2) =
"LINE"
dxf_codes(3) = 0
dxf_value(3) = "CIRCLE"

dxf_codes(4) = 0
dxf_value(4) = "ARC"
dxf_codes(5) =
0
dxf_value(5) = "POLYLINE"
dxf_codes(6) = 0

dxf_value(6) = "LWPOLYLINE"
dxf_codes(7) = -4
dxf_value(7) =
"OR>"
dbl_offst = 2

On Local Error Resume Next

ThisDrawing.SelectionSets("FindNearest").Delete
Set sst_items =
ThisDrawing.SelectionSets.Add("FindNearest")
On Local Error GoTo
0

Do While dbl_offst < MaxDistance

pnt_lleft(0) = Point1(0) - dbl_offst
    pnt_lleft(1) =
Point1(1) - dbl_offst
    pnt_urght(0) = Point1(0) +
dbl_offst
    pnt_urght(1) = Point1(1) +
dbl_offst

    sst_items.Select
acSelectionSetCrossing, pnt_lleft, pnt_urght, dxf_codes,
dxf_value
    If sst_items.Count = 1
Then
      Set ent_retrn =
sst_items.Item(0)
      Exit
Do
    ElseIf sst_items.Count > 0
Then
      'process each entity to see which one is
actually closer....
      For Each ent_check In
sst_items
        pnt_nears =
tjnLSP.ClosestPointTo(ent_check, Point1,
False)
        If Not
tjnARR.ArrayIsEmpty(pnt_nears)
Then
          dbl_distn =
tjnCAL.Distance(Point1,
pnt_nears)
          If
dbl_prevs = 0
Then
            Set
ent_retrn =
ent_check

dbl_prevs = dbl_distn

ElseIf dbl_distn < dbl_prevs
Then
            Set
ent_retrn =
ent_check

dbl_prevs = dbl_distn

End If
        End
If
        pnt_nears =
Empty
      Next

Exit Do
    End If
    dbl_offst = dbl_offst
+ 2
Loop
Set FindNearestEntity = ent_retrn
End
Function

style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">

"dan01" <
href="mailto:dshrader@lnw-inc.com">dshrader@lnw-inc.com> wrote in
message
href="news:f1a35be.1@WebX.maYIadrTaRb">news:f1a35be.1@WebX.maYIadrTaRb...
Thanks
for reply, but I know how to find the distance between a point and a line. I
was just looking for a simpler way to find the closest line to a
point.

Re:

Anonymous — Thu, 04 Dec 2003 12:59:06 GMT

Hi Dan,

Your first idea is as good as you can get. You can't expect the computer to
provide an answer without investigating every line in the set.

However, you may be able to limit the lines to investigate by creating your
selection set of lines using a crossing window.

--

Laurie Comerford
CADApps
www.cadapps.com.au

"dan01" wrote in message
news:f1a35be.1@WebX.maYIadrTaRb...
> Thanks for reply, but I know how to find the distance between a point and
a line. I was just looking for a simpler way to find the closest line to a
point.

Re:

Anonymous — Thu, 04 Dec 2003 13:38:14 GMT

Thanks you all for the help.

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Find for nearest object?

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