# Network Files¶

Network files are those that define the nodes (wards) of the network, and the links (communiting/movement) of individuals between nodes.

The Network files are a collection of files that must all exist in the same directory. They comprise;

• description.json: This file must exist in the directory, and provides the metadata needed to locate all of the other necessary files.

• work_size / play_size: These files list the index and population of

workers (in work_size) and players (in play_size) in each ward in the network. The total population in each ward (node) is the sum of the work and play populations.

• work: This file lists all of the work connections between nodes, giving the population of workers who commute from the source node to the destination.

• play: This file lists all of the play connections between nodes, giving the proportion of players who make random movements from the source node to the destination node.

• position: This file contains the coordinates of the centre of each node. These coordinates can be X/Y or latitude/longitude coordinates.

• lookup: This file contains the names and other metadata about each node, e.g. the name, local authority, region etc.

These files are all described below.

## description.json¶

This is a JSON-formatted file that provides metadata about the network model that is contained in the directory. The file describes a simple dictionary of the following key-value pairs;

• work: Filename of the work file.

• work_size: Filename of the work_size file.

• play: Filename of the play file.

• play_size: Filename of the play_size file.

• position: Filename of the position file.

• coordinates: Whether the coordinates in the position file are in x/y (x/y) or latitude/longitude (lat/long) format.

• coordinate_units: (Optional) - the units for x/y coordinates. This should be either m for meters, or km for kilometers. Distances in metawards are always reported as kilometers.

• lookup: (Optional) Filename of the lookup file.

• lookup_columns: (Optional) A dictionary that gives the column numbers (zero-indexed)for the code, name, alternate_code, alternate_name, authority_code and authority_name fields for the ward metadata.

## work¶

The work file contains the list of all work connections between nodes, giving the number of individuals who commute from the source node to the destination node. This is a column-based file with three columns of numbers that can be space or comma separated. For example;

1 1 290
1 2 3
1 5 139
1 6 59
1 7 17
1 8 119
1 9 37
1 10 121


The first number is the (1-indexed) index of the source node, while the second number is the (1-indexed) index of the destination node. The third number is the number of individuals who commute from the source to the destination node.

In this example, this lists workers who commute from ward 1 to wards 1 to 10. 290 workers commute from ward 1 to ward 1 (so work in the same ward in which they live). 3 workers commute from ward 1 to ward 2, 139 commute from ward 1 to ward 5 etc.

Note

All of the source wards have to be listed contiguously, i.e. you must list all of the connections where the source ward is equal to 1 before you list all of the connections where the source ward is equal to 2 etc.

## work_size¶

The work_size file contains the number of workers who reside in each ward. This is a column-based file with two columns of numbers that can be space or comma separated. For example;

1 6800
2 1091
3 7148
4 5684
5 7226
6 6561
7 6904
8 7213
9 6715
10 7452


The first number is the (1-indexed) index of the ward, while the second is the number of workers in that ward. The number of workers in a ward must equal the sum of the number of workers from the work file that say that they commute from that ward.

In this example, ward 1 has 6800 workers, ward 2 has 1091 workers etc.

## play¶

The play file contains the list of play connections between wards. This is a column-based file with three columns of numbers that can be space or comma separated. For example;

1 1 0.0426470588235294
1 2 0.000441176470588235
1 5 0.0204411764705882
1 6 0.00867647058823529
1 7 0.0025
1 8 0.0175
1 9 0.00544117647058823
1 10 0.0177941176470588


The first number is the (1-indexed) index of the source ward, while the second is the (1-indexed) index of the destination ward. The third number is the fraction of players who will randomly travel from the source ward to the destination ward.

In this case, 0.0426... of players will remain in ward 1, while 0.00044... of players will randomly move from ward 1 to ward 2.

Note

Be careful as the third number is a fraction (floating point number between 0 and 1) and not the number of players that move. Also note that the same ordering requirements as for the work file apply, namely that all connections for source ward 1 have to be listed before all connections for source ward 2 etc.

## play_size¶

The play_size file contains the number of players in each ward. This is a column-based file with two columns of numbers that can be space or comma separated. For example:

1 8915
2 374
3 7012
4 10579
5 8703
6 12257
7 10533
8 11259
9 8592
10 10999


The first number is the (1-indexed) index of the ward, while the second is the number of players in that ward. In this case, there are 8915 players in ward 1, 374 players in ward 2 etc.

## position¶

The position file contains the coordinates of the center of each ward. This is a column-based file with three columns of numbers that can be space or comma separated. For example:

1 524693.890435782 190136.324582048
2 532169.852194767 181663.72329877
3 522106.698233411 179737.792519091
4 533388.404693453 193451.026467071
5 525973.729674732 188464.548078951
6 523953.505171282 187729.710513154
7 520763.019103366 193360.422742775
8 523100.570665414 189524.60815157
9 523747.496973864 196638.656771657
10 523019.549069799 192050.596775831


The coordinates are either x/y or latitude/longitude, depending on what is set in the description.json file. If x/y, then the units are also set in this file.

In this case, this is for x/y coordinates in meters. The first column is the (1-indexed) index of the ward. The second column is the X coordinate, while the third is the Y coordinate.

Note

If lat/long was used, then the second column would be the latitude, and the third column the longitude.

So ward 1 has its center are (524.7km, 190.1km), while ward 2 has its center at (532.1km, 181.7km) etc.

## lookup¶

The lookup file contains metadata information about a ward that allows it to be looked up by name, region etc. This is a column-based file with a header row, and columns separated by spaces or commas. For example:

WD11CD,WD11NM,WD11NMW,CMWD11CD,CMWD11NM,CMWD11NMW,IND,LAD11CD,LAD11NM,LAD11NMW,FID
E05002337,Central,,E36000890,Central,,0,E06000039,Slough,,2001
E05002338,Chalvey,,E36000891,Chalvey,,0,E06000039,Slough,,2002
E05002339,Cippenham Green,,E36000892,Cippenham Green,,0,E06000039,Slough,,2003

The lookup_columns field in description.json specifies which columns from this file to use for the name, code, authority etc. for each ward. For example, this has set column 0 for the code, column 1 for the name, and so the first ward has code E05002337 and name Central.