Latest Contributions by JohnGaiot

Hello,  I am trying to port over an 10.3.1 script which used the old geometric network functionality in Python scripting. I am running ArcGIS Pro 2.6.2. In my script, I am creating multiple trace networks to set up a cleaned watercourse network for further hydrology and DEM processing (burning and flow directions etc). It creates the first network (wc_clean_net) to find connected segments (isolated segments are dropped) and enables the network no problem. It also successfully creates a second network (wc_net) in the same dataset (called "Layers") using an upstream trace this time from a particular pour point at the edge of the study area. But when I try to enable the network, I get the following error: 160326: The table already exists. Traceback (most recent call last): File "C:\_Workspace\Toolboxes\MNRF_TerrainToolsLocal\Pro\TerrainScripts\Step A.2. Prepare Water_new.py", line 756, in <module> arcpy.EnableNetworkTopology_tn(wc_net, "", "ENABLE_TOPO") File "c:\program files\arcgis\pro\Resources\arcpy\arcpy\tn.py", line 174, in EnableNetworkTopology raise e File "c:\program files\arcgis\pro\Resources\arcpy\arcpy\tn.py", line 171, in EnableNetworkTopology retval = convertArcObjectToPythonObject(gp.EnableNetworkTopology_tn(*gp_fixargs((in_trace_network, max_number_of_errors, only_generate_errors), True))) File "c:\program files\arcgis\pro\Resources\arcpy\arcpy\geoprocessing\_base.py", line 511, in <lambda> return lambda *args: val(*gp_fixargs(args, True)) arcgisscripting.ExecuteError: ERROR 160326: The table already exists. Failed to execute (EnableNetworkTopology). Failed to execute (CreateGeometricNetwork).‍‍‍‍‍‍‍‍‍‍‍‍ I can enable it manually by running the Toolbox command when I load the network into a map but I can't do it through python.  Below is a sample of the script. First I try to clean up previous runs of the script deleting the networks before creating them again to help try isolating the problem. I am also checking for "TN_" tables (related to the trace network) that might not be cleaned up properly from previous bailed runs. As a last ditch effort, I tried copying all input feature classes and datasets to a new geodatabase to try running on a 'clean' geodatabase. No luck. Line 58 is where it bails. # Network clean-up from previous runs arcpy.AddMessage("Checking for Networks from previous run...") if arcpy.Exists(wc_clean_net): arcpy.AddMessage(" >> Deleting 'wc_clean_net'...") arcpy.Delete_management(wc_clean_net) if arcpy.Exists(wc_net): arcpy.AddMessage(" >> Deleting 'wc_net'...") arcpy.Delete_management(wc_net) arcpy.Delete_management(WC_Clean) if arcpy.Exists(wc_select_net): arcpy.AddMessage(" >> Deleting 'wc_select_net'...") arcpy.Delete_management(wc_select_net) arcpy.Delete_management(WC_Select) #arcpy.env.workspace = Output_Vector_GDB_Workspace arcpy.AddMessage("Workspace = " + arcpy.env.workspace) CurrentLayer = "TN_*" arcpy.AddMessage("Checking for '" + CurrentLayer + "' orphan Network Tables...") GDB_Tables = arcpy.ListTables(CurrentLayer, "All") tbl_ctr = 0 for tbl in GDB_Tables: tbl_ctr += 1 arcpy.Delete_management(tbl) arcpy.AddMessage(" >> " + str(tbl_ctr) + " '" + CurrentLayer + "' tables deleted.") arcpy.AddMessage("Performing Connected Trace to create WC Clean layer...") WC_Name = os.path.basename(WC_Dissolve2) arcpy.AddMessage(" >> Dissolved WC Name = '" + WC_Name + "'") arcpy.AddMessage(" >> Creating Trace Network...") arcpy.CreateTraceNetwork_tn(Layers, "wc_clean_net", "", [[WC_Name, "SIMPLE_EDGE"]]) arcpy.AddMessage(" >> Enabling Network...") arcpy.EnableNetworkTopology_tn(wc_clean_net, "", "ENABLE_TOPO") arcpy.AddMessage(" >> Snapping buffer and pour points to network...") arcpy.Snap_edit(wc_bf_and_pour_pts, [[WC_Dissolve2, "EDGE", "0.1 Meters"]]) arcpy.AddMessage(" >> Tracing network...") # Process: Trace Geometric Network ##arcpy.TraceGeometricNetwork_management(wc_clean_net, WC_Selection3, wc_bf_and_pour_pts, "FIND_CONNECTED", "", "", "", "", "", "NO_TRACE_ENDS", "", "", "", "AS_IS", "", "", "", "AS_IS") arcpy.Trace_tn(wc_clean_net, "CONNECTED", wc_bf_and_pour_pts, "", "", "", "", "", "", "", "", "", "EDGES_ONLY", "", "", "AGGREGATED_GEOMETRY", "NEW_SELECTION", "", "Connected_Network_1", "", wc_traceout) arcpy.MultipartToSinglepart_management(wc_traceout, WC_Clean) wc_clean_lyr = "wc_clean_lyr" arcpy.MakeFeatureLayer_management(WC_Clean, wc_clean_lyr) arcpy.AddMessage(" >> Retrieving connected network results...") arcpy.AddMessage(" >> Layer name is: {0}. Count is: {1}.".format(os.path.basename(WC_Clean), str(arcpy.GetCount_management(wc_clean_lyr)))) arcpy.AddMessage("Performing Upstream Trace to create initial WC Select layer...") try: WC_Name = os.path.basename(WC_Clean) arcpy.AddMessage(" >> Cleaned WC Name = '" + WC_Name + "'") arcpy.AddMessage(" >> Creating Trace Network...") arcpy.CreateTraceNetwork_tn(Layers, "wc_net", "", [[WC_Name, "SIMPLE_EDGE"]]) except: arcpy.AddMessage(" >> Network exists... bypassing creation") arcpy.AddMessage(" >> Enabling Network...") arcpy.EnableNetworkTopology_tn(wc_net, "", "ENABLE_TOPO") arcpy.AddMessage(" >> Snapping pour points to network...") arcpy.Snap_edit(Flags_or_Sources_for_Tracing, [[WC_Clean, "EDGE", "0.1 Meters"]]) arcpy.AddMessage(" >> Tracing network...") arcpy.Trace_tn(wc_net, "UPSTREAM", Flags_or_Sources_for_Tracing, Barriers_for_Tracing, "", "", "", "", "", "", "", "", "EDGES_ONLY", "", "", "AGGREGATED_GEOMETRY", "NEW_SELECTION", "", "Upstream_Network_2", "", wc_traceout2) if Barriers_for_Tracing != "": arcpy.MultipartToSinglepart_management(wc_traceout2, Output_Vector_GDB_Workspace + "\\" + wc_inside) wc_inside_lyr = "wc_inside_lyr" arcpy.MakeFeatureLayer_management(Output_Vector_GDB_Workspace + "\\" + wc_inside, wc_inside_lyr) arcpy.AddMessage(" >> Retrieving upstream 'inside' network results...") arcpy.AddMessage(" >> Layer name is: {0}. Count is: {1}.".format(wc_inside, str(arcpy.GetCount_management(wc_inside_lyr)))) else: arcpy.MultipartToSinglepart_management(wc_traceout2, WC_Select) wc_select_lyr = "wc_select_lyr" arcpy.MakeFeatureLayer_management(WC_Select, wc_select_lyr) arcpy.AddMessage(" >> Retrieving upstream 'select' network results...") arcpy.AddMessage(" >> Layer name is: {0}. Count is: {1}.".format(os.path.basename(WC_Select), str(arcpy.GetCount_management(wc_select_lyr)))) ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ All I can think of is that the Enable function is trying to use the same system table name for the second network that was created for the first network. Am I missing something or is this a bug? Thanks, John ... View more

Similar to Ben Coakley's issue about "Function Outputs", there is practically no documentation that I can find about how to utilize the results of a trace (SELECTION option) using arcpy scripting. Basically, I want to save the selection to a layer so I can do further tracing or analysis on the derived selection. There should be an option similar to AGGREGATED_GEOMETRY which saves NON-AGGREGATED results. I don't see a rationale for aggregating geometry anyway as it produces just a single mult-part feature which seems useless to work with. Will exploding the aggregated geometry always maintain flow direction of the individual features? Even so, if there were important attributes on the original network, they would now be lost in the aggregated dissolve, which means you can't do any attribute queries or further selections on the aggregated output. By comparison, the old TraceGeometricNetwork function allowed you to work with the Group Layer output and save the results to a separate feature class with the attributes intact. I would like to see this functionality in the new Trace function (or at least the ability to save the selection with original geometry and attributes as optional output). ... View more