sewergraph 0.1.4

Tools for graph calculations on sewer networks

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()

	total_area	OBJECTID	facilityid	pipeshape	diameter	height	width	length	slope	material	STREET	local_area	geometry
19	4,233,504	112545	A58064DF	BOX	0	12	16	327.279370	0.0075	RCP	None	119043.524941	LINESTRING (6558821.45028765 2032961.24586616,...
18	4,114,461	112546	5890D18F	BOX	0	12	16	318.081402	0.0100	RCP	None	171961.403740	LINESTRING (6558826.08945222 2032643.19829701,...
24	3,942,499	112563	12FF7372	BOX	0	12	16	131.352534	0.0100	RCP	None	16557.605522	LINESTRING (6558821.78250872 2032511.9163921, ...

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.