topic Re: Create lines from points and cut rectangle with line and assign attributes in Python Questions

Create lines from points and cut rectangle with line and assign attributes

TimGattinger1 — Tue, 28 Mar 2017 20:15:19 GMT

Ok, attached I have the point data and the rectangle as polygon. I want to draw vertical line from each point (from the top to the bottom) and keep the information written in the LN column. After I want to make single polygons (resulting from the underlying rectangle and the lines together) and also keep the LN information in the single polygons. So in the end it shoudl be 13 single polygons, I hope you understand what I mean.

Best,

Tim

Dropbox - GW1.zip

Branched from: https://community.esri.com/thread/176544

Re: Create lines from points and cut rectangle with line and assign attributes

XanderBakker — Fri, 31 Mar 2017 02:53:18 GMT

When I look at the data I see that you are using a format (point featureclass) that is different from the original format used in the thread Create a line from points using attributes

I understand that you want to create vertical lines and use these to cut a rectangle in smaller parts in order to generate the smaller rectangles and assign values from the attributes of the input points. This may not be as straight forward as you hope, since the input points do not hold details on which points should be used together to form the line (although this will probably be those with the same X-coordinates):

I would like to suggest another input format (if possible) to make this process a lot easier. You basically have a constant Y (min and max) and a Xmin. When you know the width of each rectangle and you start with Xmin and apply the width you will be able to form the rectangles with little effort and it will be easy to maintain the attributes (for instance field LN):

Could you elaborate a little on what the data represents and where it comes from and what you want to achieve (apart from the smaller rectangles)?

Kind regards, Xander

Re: Create lines from points and cut rectangle with line and assign attributes

XanderBakker — Sat, 11 Dec 2021 08:39:23 GMT

Hi Tim Gattinger , see below the code I created based on the information in the point shapefile:

#-------------------------------------------------------------------------------
# Name:        create_rectangles.py
# Purpose:
#
# Author:      Xander
#
# Created:     01-04-2017
#-------------------------------------------------------------------------------
import arcpy
import os

def main():
    arcpy.env.overwriteOutput = True

    # parameters
    fc_in = r'C:\GeoNet\GW1\ref_kal_ln\ref_kal_ln.shp'
    fc_out = r'C:\GeoNet\GW1\rectangles_v01.shp'
    where = '"ID" <14'
    fld_x_max = 'X'
    fld_y_max = 'Y'
    fld_width = 'width'
    fld_height = 'length'

    # create output featureclass
    sr = arcpy.Describe(fc_in).spatialReference
    CreateFeatureClassTemplate(fc_out, fc_in, "POLYGON", fc_in, sr)

    # nested insert and search cursor
    flds = GetAllFieldsWithoutSystemFields(fc_in)
    with arcpy.da.InsertCursor(fc_out, flds) as curs_out:
        with arcpy.da.SearchCursor(fc_in, flds, where) as curs:
            for row in curs:
                x_max = row[flds.index(fld_x_max)]
                y_max = row[flds.index(fld_y_max)]
                width = row[flds.index(fld_width)]
                height = row[flds.index(fld_height)]

                polygon = CreateRectangle(x_max, y_max, width, height, sr)
                if polygon is not None:
                    lst_row = list(row)
                    lst_row[0] = polygon
                    row_out = tuple(lst_row)
                    curs_out.insertRow(row_out)


def GetAllFieldsWithoutSystemFields(fc):
    flds = [fld.name for fld in arcpy.ListFields(fc)]
    desc = arcpy.Describe(fc)
    fld_shape = desc.shapeFieldName
    fld_oid = desc.OIDFieldName
    for fld_name in [fld_shape, fld_oid]:
        if fld_name in flds:
            flds.pop(flds.index(fld_name))
    flds.insert(0, 'SHAPE@')
    return flds


def CreateFeatureClassTemplate(fc_out, fc_in, geomtype, template,  sr):
    ws_name, fc_name = os.path.split(fc_out)
    arcpy.CreateFeatureclass_management(ws_name, fc_name, geomtype, template, spatial_reference=sr)


def CreateRectangle(x_max, y_max, width, height, sr):
    pnt1 = arcpy.Point(x_max - width, y_max - height)
    pnt2 = arcpy.Point(x_max - width, y_max)
    pnt3 = arcpy.Point(x_max, y_max)
    pnt4 = arcpy.Point(x_max, y_max - height)
    lst_pnts = [pnt1, pnt2, pnt3, pnt4, pnt1]
    return arcpy.Polygon(arcpy.Array(lst_pnts), sr)


if __name__ == '__main__':
    main()‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

The upper part of the shapefile looks like this:

The attribute table of the resulting shapefile (attributes are transferred):

I have attached the resulting shapefile for you to examine.

Re: Create lines from points and cut rectangle with line and assign attributes

TimGattinger1 — Thu, 18 May 2017 14:32:26 GMT

Dear Xander,

may I send you a message? Afaik in this community it only works if you would follow me..

Re: Create lines from points and cut rectangle with line and assign attributes

XanderBakker — Thu, 18 May 2017 15:04:34 GMT

Sure, I will follow you.