sewergraph

v0.1.4

Building upon Networkx, this package provides tools for analysis and manipulation of sewer network data.

Goals

Provide graph functions to tackle analytical problems typical in sewer collections systems:

• traverse sewer networks up/downstream
• accumulation calculations
• downstream choke-point analysis
• data gap handling (within reason, folks)
• design capacity analysis

Installation

Inspired by osmnx, sewergraph depends on Networkx and Pandas. For most use cases, installation is easy:

$ pip install sewergraph

Additional functionality is provided that makes use of GeoPandas, scipy and Shapely. It's recommended to install GeoPandas with conda first, then install sewergraph via pip:

$ conda install geopandas
$ pip install sewergraph

If you have ArcMap installed, be sure that the GeoPandas installation doesn't conflict with arcpy. To avoid risks, install sewergraph in a conda environment:

$ conda create --name myenv
$ activate myenv #enter the new environment
$ conda install geopandas
$ pip install sewergraph

Examples

Create a Networkx DiGraph with a shapefile of a sewer network.

import sewergraph as sg

#read shapefile into DiGraph
shapefile_path = r'path/to/sewers.shp'
G = sg.graph_from_shp(shapefile_path)

Attributes of each sewer segment are stored as edge data. Geometry is parse and stored in the geometry attribute along with whatever other fields exist in the shapefile.

#sewer connecting node 0 to node 1
print(G[0][1])

{
  'OBJECTID': 115081,
  'STREET': 'ADAINVILLE DR',
  'ShpName': 'sample_sewer_network_1',
  'diameter': 8,
  'facilityid': 'BCE7B25E',
  'geometry': <shapely.geometry.linestring.LineString at 0x12a6caf0>,
  'height': 0,
  'length': 164.758,
  'local_area': 39449.474,
  'material': 'VCP',
  'pipeshape': 'CIR',
  'slope': 0.01,
  'width': 0
}

Calculate the total drainage area at each sewer by accumulating local_area from the top to bottom of the network (i.e. sewershed).

#accumulate drainage area
G = sg.accumulate_downstream(G, 'local_area', 'total_area')

#convert to GeoDataFrame and sort the sewers by total_area
sewers = sg.gdf_from_graph(G)
sewers = sewers.sort_values(by = 'total_area', ascending=False)
sewers.head()

More functions are provided for calculating basic hydraulic capacity, outfall loading, flow splits, travel time, and identifying downstream constrictions from every point of the network.

#perform basic sewer capacity calculations (full flow Mannings capacity)
G = hhcalcs_on_network(G)

#id flow split sewers and calculate split fractions
G = analyze_flow_splits(G)

#accumulating travel times
G = accumulate_travel_time(G)

Running Tests

Test are located in the sewergraph > tests directory and are run with pytest.