Build Network Dataset with python comtypes
OK going to have a stab at this:
Most of your code appears to be building a Network dataset but this line
fdx = fdxc.FindExtension(esriGeoDatabase.esriDatasetType(7)) # get error here
is trying to return a GeometricNetwork (7), have a try at returning a Networkdataset (19)?
I've also created a script that creates a Network Dataset using comtypes and arcobjects COM Objects. The information posted here, these two GIS-se posts and the ArcGIS tutorial linked in the question were extremely helpful me in putting this together. I went into a little more depth in configuring the network attributes and other settings of the Network Dataset than what is in the content of the question and answers here so I'm posting my code (which is a solution to the question posed fwiw) in hopes that it may be helpful to others. The script below does import a couple of things from other python modules and those references can be seen in this github repo which hosts the larger project that this is a part of.
from datetime import datetime
from os.path import basename, join
from arcpy import env, CheckInExtension, GetInstallInfo
from comtypes.client import CreateObject, GetModule
ARCOBJECTS_DIR = join(GetInstallInfo()['InstallDir'], 'com')
GetModule(join(ARCOBJECTS_DIR, 'esriDataSourcesFile.olb'))
GetModule(join(ARCOBJECTS_DIR, 'esriGeoDatabase.olb'))
GetModule(join(ARCOBJECTS_DIR, 'esriSystem.olb'))
from comtypes.gen.esriDataSourcesGDB import FileGDBWorkspaceFactory
from comtypes.gen.esriGeoDatabase import esriDatasetType, \
esriNetworkAttributeDataType, esriNetworkAttributeUnits, \
esriNetworkAttributeUsageType, esriNetworkDatasetType, \
esriNetworkEdgeConnectivityPolicy, esriNetworkEdgeDirection, \
esriNetworkElementType, DENetworkDataset, EdgeFeatureSource, \
EvaluatedNetworkAttribute, IDataElement, IDataset, IDatasetContainer3, \
IDEGeoDataset, IDENetworkDataset2, IEdgeFeatureSource, IEnumDataset, \
IEvaluatedNetworkAttribute, IFeatureDatasetExtension, \
IFeatureDatasetExtensionContainer, IFeatureWorkspace, IGeoDataset, \
INetworkAttribute2, INetworkBuild, INetworkDataset, \
INetworkConstantEvaluator, INetworkEvaluator, INetworkFieldEvaluator2, \
INetworkSource, IWorkspace, IWorkspaceFactory, IWorkspaceExtension3, \
IWorkspaceExtensionManager, NetworkConstantEvaluator, \
NetworkFieldEvaluator
from comtypes.gen.esriSystem import IArray, IUID, UID
from lightraildev.common import checkout_arcgis_extension, ATTRIBUTE_LEN, \
ATTRIBUTE_MIN, ATTRIBUTE_PED, OSM_PED_FC, OSM_PED_FDS, OSM_PED_GDB, \
OSM_PED_ND
# for some reason esriSystem.Array objects can't be created normally
# via comtypes, I found a workaround on pg 7 of the linked pdf, below is
# the object's GUID which can be supplied in place of the object
# http://www.pierssen.com/arcgis10/upload/python/arcmap_and_python.pdf
ARRAY_GUID = "{8F2B6061-AB00-11D2-87F4-0000F8751720}"
FDS_NAME = basename(OSM_PED_FDS)
FC_NAME = basename(OSM_PED_FC)
ND_NAME = basename(OSM_PED_ND)
def create_gdb_network_dataset():
""""""
# create an empty data element for a buildable network dataset
net = new_obj(DENetworkDataset, IDENetworkDataset2)
net.Buildable = True
net.NetworkType = esriNetworkDatasetType(1)
# open the feature class and ctype to the IGeoDataset interface
gdb_ws_factory = new_obj(FileGDBWorkspaceFactory, IWorkspaceFactory)
gdb_workspace = ctype(gdb_ws_factory.OpenFromFile(OSM_PED_GDB, 0),
IFeatureWorkspace)
gdb_feat_ds = ctype(gdb_workspace.OpenFeatureDataset(FDS_NAME),
IGeoDataset)
# copy the feature dataset's extent and spatial reference to the
# network dataset data element
net_geo_elem = ctype(net, IDEGeoDataset)
net_geo_elem.Extent = gdb_feat_ds.Extent
net_geo_elem.SpatialReference = gdb_feat_ds.SpatialReference
# specify the name of the network dataset
net_element = ctype(net, IDataElement)
net_element.Name = ND_NAME
edge_net = new_obj(EdgeFeatureSource, INetworkSource)
edge_net.Name = FC_NAME
edge_net.ElementType = esriNetworkElementType(2)
# set the edge feature source's connectivity settings, connect
# network through any coincident vertex
edge_feat = ctype(edge_net, IEdgeFeatureSource)
edge_feat.ClassConnectivityGroup = 1
edge_feat.ClassConnectivityPolicy = esriNetworkEdgeConnectivityPolicy(0)
edge_feat.UsesSubtypes = False
source_array = new_obj(ARRAY_GUID, IArray)
source_array.Add(edge_net)
net.Sources = source_array
add_network_attributes(net, edge_net)
# get the feature dataset extension and create the network dataset
# based on the data element.
osm_data_xc = ctype(gdb_feat_ds, IFeatureDatasetExtensionContainer)
osm_data_ext = ctype(osm_data_xc.FindExtension(esriDatasetType(19)),
IFeatureDatasetExtension)
osm_data_cont = ctype(osm_data_ext, IDatasetContainer3)
net_dataset = ctype(osm_data_cont.CreateDataset(net), INetworkDataset)
# once the network dataset is created, build it
net_build = ctype(net_dataset, INetworkBuild)
net_build.BuildNetwork(net_geo_elem.Extent)
def add_network_attributes(net, edge_net):
""""""
attribute_array = new_obj(ARRAY_GUID, IArray)
language = 'VBScript'
# 1) 'ped_permissions' attribute establishes the streets and trails that
# pedestrians can and cannot be routed along
ped_eval_attr = new_obj(EvaluatedNetworkAttribute,
IEvaluatedNetworkAttribute)
ped_attr = ctype(ped_eval_attr, INetworkAttribute2)
ped_attr.DataType = esriNetworkAttributeDataType(3) # boolean
ped_attr.Name = ATTRIBUTE_PED
ped_attr.Units = esriNetworkAttributeUnits(0) # unknown
ped_attr.UsageType = esriNetworkAttributeUsageType(2) # restriction
ped_attr.UseByDefault = True
ped_expr = 'restricted'
ped_logic = (
'Set foot_list = CreateObject("System.Collections.ArrayList")' '\n'
'foot_list.Add "designated"' '\n'
'foot_list.Add "permissive"' '\n'
'foot_list.Add "yes"' '\n\n'
'Set hwy_list = CreateObject("System.Collections.ArrayList")' '\n'
'hwy_list.Add "construction"' '\n'
'hwy_list.Add "motorway"' '\n'
'hwy_list.Add "trunk"' '\n\n'
'If foot_list.Contains([foot]) Then' '\n'
' restricted = False' '\n'
'ElseIf _' '\n'
' ([access] = "no") Or _' '\n'
' ([foot] = "no") Or _' '\n'
' ([indoor] = "yes") Or _' '\n'
' (hwy_list.Contains([highway])) Then' '\n'
' restricted = True' '\n'
'Else' '\n'
' restricted = False' '\n'
'End If'
)
set_evaluator_logic(ped_eval_attr, edge_net, ped_expr, ped_logic, language)
set_evaluator_constants(ped_eval_attr, False)
attribute_array.Add(ped_eval_attr)
# 2) 'length' attribute, in feet
len_eval_attr = new_obj(EvaluatedNetworkAttribute,
IEvaluatedNetworkAttribute)
len_attr = ctype(len_eval_attr, INetworkAttribute2)
len_attr.DataType = esriNetworkAttributeDataType(2) # double
len_attr.Name = ATTRIBUTE_LEN
len_attr.Units = esriNetworkAttributeUnits(3) # feet
len_attr.UsageType = esriNetworkAttributeUsageType(0) # cost
len_attr.UseByDefault = True
len_expr = '[Shape]'
set_evaluator_logic(len_eval_attr, edge_net, len_expr, '', language)
set_evaluator_constants(len_eval_attr, 0)
attribute_array.Add(len_eval_attr)
# 3) 'minutes' attribute, assumes a walking speed of 3 mph
min_eval_attr = new_obj(EvaluatedNetworkAttribute,
IEvaluatedNetworkAttribute)
min_attr = ctype(min_eval_attr, INetworkAttribute2)
min_attr.DataType = esriNetworkAttributeDataType(2) # double
min_attr.Name = ATTRIBUTE_MIN
min_attr.Units = esriNetworkAttributeUnits(21) # minutes
min_attr.UsageType = esriNetworkAttributeUsageType(0) # cost
min_attr.UseByDefault = True
min_expr = 'walk_minutes'
min_logic = 'walk_minutes = [Shape] / (5280 * (3 / 60))'
set_evaluator_logic(min_eval_attr, edge_net, min_expr, min_logic, language)
set_evaluator_constants(min_eval_attr, 0)
attribute_array.Add(min_eval_attr)
net.Attributes = attribute_array
def set_evaluator_logic(eval_attr, edge_net, expression, pre_logic, lang):
"""This function implements the same logic for an attribute in
both the along and against directions
"""
# for esriNetworkEdgeDirection 1=along, 2=against
for direction in (1, 2):
net_eval = new_obj(NetworkFieldEvaluator, INetworkFieldEvaluator2)
net_eval.SetLanguage(lang)
net_eval.SetExpression(expression, pre_logic)
eval_attr.Evaluator.setter(
eval_attr, edge_net, esriNetworkEdgeDirection(direction),
ctype(net_eval, INetworkEvaluator))
def set_evaluator_constants(eval_attr, constant):
"""This function sets all evaluator constants to the same value"""
# for ConstantValue False means traversable (that is, not restricted),
# for esriNetworkElementType 1=junction, 2=edge, 3=turn
for element_type in (1, 2, 3):
const_eval = new_obj(NetworkConstantEvaluator,
INetworkConstantEvaluator)
const_eval.ConstantValue = constant
eval_attr.DefaultEvaluator.setter(
eval_attr, esriNetworkElementType(element_type),
ctype(const_eval, INetworkEvaluator))
# the following two functions are derived from the linked module and make the
# code more VB.net(ic) the language from which the tutorial this code from is
# written in, all they really do is make comtypes functionality slightly less
# verbose, but that's valuable since they're called so many times
# http://www.pierssen.com/arcgis10/upload/python/snippets102.py
def new_obj(class_, interface):
"""Creates a new comtypes POINTER object where 'class_' is the class
to be instantiated, 'interface' is the interface to be assigned
"""
pointer = CreateObject(class_, interface=interface)
return pointer
def ctype(obj, interface):
"""Casts obj to interface and returns comtypes POINTER"""
pointer = obj.QueryInterface(interface)
return pointer
def main():
""""""
env.overwriteOutput = True
checkout_arcgis_extension('Network')
create_gdb_network_dataset()
CheckInExtension('Network')
if __name__ == '__main__':
main()