topic Re: Draw Perpendicular Line. in Python Questions

Draw Perpendicular Line.

RajP — Thu, 25 Feb 2016 08:29:52 GMT

Hello,

Can anyone suggest me to draw the perpendicular line for very point automatically using python/arcobject. That Perpendicular line touch with line feature. Kindly reference the below image.

Regards,

Raj

Re: Draw Perpendicular Line.

DanPatterson_Retired — Thu, 25 Feb 2016 10:58:19 GMT

Darren Wiens posted some code here which should get you started. Your normals are to the X-axis rather than relative to the line. You can construct an intersecting line relative to that axis which should give you the necessary point intersection on your line and hence the point-line segment

Re: Draw Perpendicular Line.

XanderBakker — Sat, 11 Dec 2021 10:59:49 GMT

The code below seems to do the job, BUT this is based on a single line. If you have several polylines you will have to include logic to select the polyline to "snap to".

import arcpy

def main():
    fc_lines = r'D:\Xander\GeoNet\Perpendicular\data.gdb\lines'
    fc_points = r'D:\Xander\GeoNet\Perpendicular\data.gdb\points'
    fc_out = r'D:\Xander\GeoNet\Perpendicular\data.gdb\result'
    tolerance = 15000

    # get first line
    polyline = arcpy.da.SearchCursor(fc_lines, ('SHAPE@')).next()[0]

    lines = []
    with arcpy.da.SearchCursor(fc_points, ('SHAPE@')) as curs:
        for row in curs:
            pnt = row[0]
            line = createVerticalLine(pnt.firstPoint, tolerance, pnt.spatialReference)
            mp = getIntersectingPoints(line, polyline)
            if mp.pointCount > 0:
                pnt2 = getNearestPoint(mp, pnt.firstPoint)
                vert_line = arcpy.Polyline(arcpy.Array([pnt.firstPoint, pnt2]),
                                       pnt.spatialReference)
                lines.append(vert_line)
            else:
                # no intersecting within tolerance
                pass

    arcpy.CopyFeatures_management(lines, fc_out)

def createVerticalLine(pnt, tolerance, sr):
    return arcpy.Polyline(arcpy.Array([arcpy.Point(pnt.X, pnt.Y+tolerance),
                                       arcpy.Point(pnt.X, pnt.Y-tolerance)]),
                                       sr)

def getIntersectingPoints(line, polyline):
    return polyline.intersect(line, 1)

def getNearestPoint(mp, pnt):
    nearest_pnt = None
    for p in mp:
        if nearest_pnt is None:
            nearest_pnt = p
            min_dist = getDistance(p, pnt)
        else:
            dist = getDistance(p, pnt)
            if dist < min_dist:
                nearest_pnt = p
                min_dist = dist
    return nearest_pnt

def getDistance(p1, p2):
    import math
    return math.sqrt((p1.X-p2.X)**2 + (p1.Y-p2.Y)**2)

if __name__ == '__main__':
    main()

Re: Draw Perpendicular Line.

DarrenWiens2 — Thu, 25 Feb 2016 16:35:42 GMT

Are you looking for a perpendicular line (90 degrees to the line, as I've added below) or a vertical line (as you've drawn)?

Re: Draw Perpendicular Line.

DanPatterson_Retired — Thu, 25 Feb 2016 17:15:58 GMT

he wants normal to the x-axis rather than your example of normal to the line,

Re: Draw Perpendicular Line.

RajP — Tue, 01 Mar 2016 06:15:50 GMT

Hi,

I need vertical line for each point and touch with line feature.

Regards,

Raj P

Re: Draw Perpendicular Line.

M_DJohnson — Sat, 20 May 2017 06:40:49 GMT

IProximityOperator proximity = <<PolylineFeature>>.ShapeCopy as IProximityOperator;

IPoint out_point = proximity.ReturnNearestPoint(<<input point>>, esriSegmentExtension.esriExtendTangentAtFrom);

Try this code, it will create perpendicular lines to given point.

Re: Draw Perpendicular Line.

XanderBakker — Sat, 20 May 2017 14:21:34 GMT

True, but if you look at the examples you will see that it was not a perpendicular line the OP was looking for.