FindBraidedNetwork.py

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# Name:             Find Braided Reaches in Stream Network                          #
# Purpose:          Find Braided Reaches as part of network preprocessing steps.    #
#                                                                                   #
# Author:           Kelly Whitehead (kelly@southforkresearch.org)                   #
#                   Jesse Langdon                                                   #
#                   South Fork Research, Inc                                        #
#                   Seattle, Washington                                             #
#                                                                                   #
# Created:          2014-Sept-30                                                    #
# Version:          2.0 beta                                                        #
# Modified:         2017-Feb-16                                                     #
# Documentation:    http://gnat.riverscapes.xyz/                                    #
#                                                                                   #
# Copyright:        (c) Kelly Whitehead, Jesse Langdon 2017                         #
#                                                                                   #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#!/usr/bin/env python

# Import modules
import os
import sys
import arcpy


def main(fcStreamNetwork, canal, tempDir, perennial_network, is_verbose):
    # Polyline prep

    arcpy.env.outputZFlag = "Disabled"
    arcpy.env.outputMFlag = "Disabled"

    if is_verbose:
        arcpy.AddMessage("Checking input fields and if canals shapefile exists...")
    listFields = arcpy.ListFields(fcStreamNetwork,"IsMultiCh")
    if len(listFields) is not 1:
        arcpy.AddField_management(fcStreamNetwork, "IsMultiCh", "SHORT", "", "", "", "", "NULLABLE")
    arcpy.CalculateField_management(fcStreamNetwork,"IsMultiCh",0,"PYTHON")

    # Process
    if canal is None:
        findBraidedReaches(fcStreamNetwork, perennial_network, is_verbose)
    else:
        handleCanals(fcStreamNetwork, canal, perennial_network, tempDir, is_verbose)

    use_stream_names(fcStreamNetwork)
    return


def use_stream_names(stream_network):
    fields = arcpy.ListFields(stream_network)
    if "StreamName" in fields:
        new_name = "StreamName"
    elif "GNIS_Name" in fields:
        new_name = "GNIS_Name"
    else:
        new_name = False
    if new_name:
        with arcpy.da.UpdateCursor(stream_network, ["IsMultiCh", "IsMainCh", new_name]) as cursor:
            for row in cursor:
                if row[0] == 1 and row[2] != ' ':
                    row[1] = 1
                    cursor.updateRow(row)


def handleCanals(stream_network, canal, perennial_network, temp_folder, is_verbose):
    """
    Finds braided sections of the stream network, not counting canals, if canals are available
    :param stream_network:
    :param canal:
    :param temp_folder:
    :param is_verbose:
    :return:
    """
    if is_verbose:
        arcpy.AddMessage("Removing canals...")
    if arcpy.GetInstallInfo()['Version'][0:4] == '10.5':
        stream_network_no_canals = os.path.join(temp_folder, "NoCanals.shp")
        perennial_no_canals = os.path.join(temp_folder, "PerenNoCanals.shp")
    else:
        stream_network_no_canals = os.path.join('in_memory', 'NoCanals')
        perennial_no_canals = os.path.join('in_memory', "PerenNoCanals")

    arcpy.Erase_analysis(stream_network, canal, stream_network_no_canals)
    if perennial_network is not None:
        arcpy.Erase_analysis(perennial_network, canal, perennial_no_canals)
    else:
        perennial_no_canals = None
    findBraidedReaches(stream_network_no_canals, perennial_no_canals, is_verbose)

    with arcpy.da.UpdateCursor(stream_network_no_canals, "IsMultiCh") as cursor: # delete non-braided reaches
        for row in cursor:
            if row[0] == 0:
                cursor.deleteRow()

    arcpy.MakeFeatureLayer_management(stream_network, "lyrBraidedReaches")
    arcpy.MakeFeatureLayer_management(stream_network_no_canals,"lyrNoCanals")

    arcpy.SelectLayerByLocation_management("lyrBraidedReaches","SHARE_A_LINE_SEGMENT_WITH","lyrNoCanals",'',"NEW_SELECTION")

    arcpy.CalculateField_management("lyrBraidedReaches","IsMultiCh",1,"PYTHON")
    arcpy.CalculateField_management("lyrBraidedReaches","IsMainCh",0,"PYTHON")

    arcpy.Delete_management(stream_network_no_canals)


def findBraidedReaches(fcLines, perennial_network, is_verbose):
    if is_verbose:
        arcpy.AddMessage("Finding streams with mutltiple channels...")
    # Clear temporary data
    if arcpy.Exists("in_memory//DonutPolygons"):
        arcpy.Delete_management("in_memory//DonutPolygons")
    if arcpy.Exists("lyrDonuts"):
        arcpy.Delete_management("lyrDonuts")
    if arcpy.Exists("lyrBraidedReaches"):
        arcpy.Delete_management("lyrBraidedReaches")

    # Find donut reaches
    donut_polygons = "in_memory/DonutPolygons"
    if perennial_network is not None:
        arcpy.FeatureToPolygon_management(perennial_network, donut_polygons)
    else:
        arcpy.FeatureToPolygon_management(fcLines, donut_polygons)

    # delete extremely large donuts (< 0.5 sq km) since these are false positives for finding side channels
    with arcpy.da.UpdateCursor(donut_polygons, ['SHAPE@AREA']) as cursor:
        for row in cursor:
            if row[0] > 500000:
                cursor.deleteRow()

    arcpy.MakeFeatureLayer_management(donut_polygons,"lyrDonuts")
    arcpy.MakeFeatureLayer_management(fcLines,"lyrBraidedReaches")

    arcpy.SelectLayerByLocation_management("lyrBraidedReaches","SHARE_A_LINE_SEGMENT_WITH","lyrDonuts",'',"NEW_SELECTION")
    arcpy.CalculateField_management("lyrBraidedReaches","IsMultiCh",1,"PYTHON")
    arcpy.CalculateField_management("lyrBraidedReaches","IsMainCh",0,"PYTHON")

# # Run as Script # # 
if __name__ == "__main__":

    main(sys.argv[1])