GMNSΒΆ

GMNS (General Modeling Network Specification), proposed by the Zephyr Foundation, which aims to advance the field through flexible and efficient support, education, guidance, encouragement, and incubation.

The two necessary files used in GMNS to describe a network: node.csv and link.csv.

  • node.csv

The node file is a list of vertices that locate points on a map. Typically, they will represent intersections, but may also represent other points, such as a transition between divided and undivided highway[1]. We add several additional attributes to the node file to make it more suitable for transportation modelling. Detailed node data dictionary is listed below.

Field

Type

Required?

Comments

name

string

node_id

int

yes

unique key

osm_node_id

string or int

corresponding point id in osm data

osm_highway

string

point type in osm data

zone_id

int

ctrl_type

int

1: Signalized; 0: not

node_type

string

activity_type

string

defined by adjacent links

is_boundary

bool

1: boundary; 0: not

x_coord

double

yes

WGS 84 is used in osm

y_coord

double

yes

WGS 84 is used in osm

main_node_id

int

nodes belonging to one complex intersection have the same id

poi_id

int

id of the corresponding poi

  • link.csv

A link is an edge in a network, defined by the nodes it travels from and to. It may have associated geometry information[2]. Similar to node.csv, We also added several new attributes to the link file. Detailed link data dictionary is listed below.

Field

Type

Required?

Comments

name

string

link_id

int

yes

unique key

osm_way_id

string or int

corresponding way id in osm data

from_node_id

int

yes

to_node_id

int

yes

dir_flag

enum

1: forward, -1: backward, 0:bidirectionial

length

float

unit: meter

lanes

int

free_speed

float

capacity

float

unit: veh/hr/lane

link_type_name

string

link_type

int

geometry

Geometry

wkt

allowed_uses

enum

auto, bike, walk

from_biway

bool

1: link created from a bidirectional way, 0: not

Other two optional files including movement.csv and segement.csv follow the exact same format as what being defined in the GMMS standard. Readers can check the GMNS website for details.

In addition to the above files defined in the GMNS standard, osm2gmns can also produce poi.csv files where point of interest information is stored. Detailed poi data dictionary is listed below.

Field

Type

Required?

Comments

name

string

poi_id

int

yes

unique key

osm_way_id

string or int

corresponding way id in osm data

osm_relation_id

string or int

corresponding relation id in osm data

building

string

building tag in osm data

amenity

string

amenity tag in osm data

geometry

Geometry

yes

wkt

centroid

Geometry

wkt

[1] https://github.com/zephyr-data-specs/GMNS/blob/master/Specification/Node.md

[2] https://github.com/zephyr-data-specs/GMNS/blob/master/Specification/Link.md