Reference

Keyword arguments

SylvereyeRoadNetwork is the core component of the Dash Sylvereye library.

Import it from the dash_sylvereye module:

from dash_sylvereye import SylvereyeRoadNetwork

SylvereyeRoadNetwork accepts 21 keyword arguments, grouped into six categories:

Dash keyword arguments
Data keyword arguments
Options keyword arguments
Show/hide keyword arguments
Map keyword arguments
Tile-layer keyword arguments

A complete picture of every keyword argument, with its default value:

SylvereyeRoadNetwork(# Dash keyword arguments
                     id='',
                     # Data keyword arguments
                     nodes_data=[],
                     edges_data=[],
                     markers_data=[],
                     # Options keyword arguments
                     node_options={ see below },
                     edge_options={ see below },
                     marker_options={ see below },
                     debug_options={},
                     # Show/hide keyword arguments
                     show_nodes=True,
                     show_edges=True,
                     show_arrows=True,
                     show_markers=True,
                     # Map keyword arguments
                     map_center=[],
                     map_zoom=3,
                     map_min_zoom=3,
                     map_max_zoom=20,
                     map_style={},
                     # Tile layer keyword arguments
                     tile_layer_url='https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
                     tile_layer_subdomains='',
                     tile_layer_attribution='&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors',
                     tile_layer_opacity=1.0)

None of the keyword arguments are mandatory.

Thanks to Dash's callback architecture, every SylvereyeRoadNetwork keyword argument other than id can be updated at runtime to drive the visualization, typically in response to the user's interaction with other Dash components.

Dash keyword arguments

These are the keyword arguments mandated by Dash itself. For now there is only one, id:

`id`

Kind: SylvereyeRoadNetwork component keyword argument
Type: str
Default: Empty string

The identifier of the Dash component.

Data keyword arguments

SylvereyeRoadNetwork needs two pieces of data to describe a road-network topology: nodes and edges. They are supplied separately through the nodes_data and edges_data keyword arguments.

You usually populate nodes_data and edges_data from OSMnx-generated data using the load_from_osmnx_graph and load_from_osmnx_graphml helpers, but you can also build the lists by hand.

SylvereyeRoadNetwork also supports map markers, supplied through the markers_data keyword argument.

You usually populate markers_data from a list of coordinate pairs with the generate_markers_from_coords helper, but again you can build the list by hand if you prefer.

`nodes_data`

Kind: SylvereyeRoadNetwork component keyword argument
Type: list of dict
Default: Empty list

The list of the road network's nodes. Each item must be a node. See the nodes data format for the schema each node item must follow.

`edges_data`

Kind: SylvereyeRoadNetwork component keyword argument
Type: list of dict
Default: Empty list

The list of the road network's edges. Each item must be an edge. See the edges data format for the schema each edge item must follow.

`markers_data`

Kind: SylvereyeRoadNetwork component keyword argument
Type: list of dict
Default: Empty list

The list of map markers. Each item must be a marker. See the markers data format for the schema each marker item must follow.

Options keyword arguments

The visualization options for nodes, edges, and markers are supplied as separate dictionaries.

node_options controls the color, size, and transparency methods used for nodes.

The usual flow: fetch a pre-filled default with get_default_node_options, override the keys you care about, and pass the result to SylvereyeRoadNetwork as node_options.

edge_options controls the color, width, and transparency methods used for edges.

The usual flow: fetch a pre-filled default with get_default_edge_options, override the keys you care about, and pass the result to SylvereyeRoadNetwork as edge_options.

marker_options controls the color, size, transparency, and icon methods used for markers.

The usual flow: fetch a pre-filled default with get_default_marker_options, override the keys you care about, and pass the result to SylvereyeRoadNetwork as marker_options.

`node_options`

Kind: SylvereyeRoadNetwork component keyword argument
Type: dict
Default:

{
    'color_method': NodeColorMethod.DEFAULT,
    'size_method': NodeSizeMethod.DEFAULT,
    'alpha_method': NodeAlphaMethod.DEFAULT,
    'visibility_method': NodeVisibilityMethod.ALWAYS,
    'color_default': 0xa10000,
    'size_default': 0.005,
    'alpha_default': 1.0
}

The visual options dictionary for nodes. See Node options for the supported keys and their semantics.

`edge_options`

Kind: SylvereyeRoadNetwork component keyword argument
Type: dict
Default:

{
    'color_method': EdgeColorMethod.DEFAULT,
    'width_method': EdgeWidthMethod.DEFAULT,
    'alpha_method': EdgeAlphaMethod.DEFAULT,
    'visibility_method': EdgeVisibilityMethod.ALWAYS,
    'color_default': 0x06696,
    'width_default': 0.25,
    'alpha_default': 1.0,
    'alpha_min': 0.0,
    'show_edge_hit_polygons': False
}

The visual options dictionary for edges. See Edge options for the supported keys and their semantics.

`marker_options`

Kind: SylvereyeRoadNetwork component keyword argument
Type: dict
Default:

{
    'color_method': MarkerColorMethod.DEFAULT,
    'icon_method': MarkerIconMethod.DEFAULT,
    'size_method': MarkerSizeMethod.DEFAULT,
    'alpha_method': MarkerAlphaMethod.DEFAULT,
    'visibility_method': MarkerVisibilityMethod.ALWAYS,
    'color_default': 0x066cc,
    'size_default': 0.5,
    'size_default_scale_min': 0.25,
    'size_default_scale_max': 0.5,
    'alpha_default': 1.0,
    'enable_tooltips': False,
    'enable_zoom_scaling': False
}

The visual options dictionary for markers. See Marker options for the supported keys and their semantics.

`debug_options`

Kind: SylvereyeRoadNetwork component keyword argument
Type: dict
Default: Empty dictionary

The debug options. #TODO

Show/hide keyword arguments

You can hide any combination of the four visualization layers (nodes, edges, direction arrows, markers) with the show_nodes, show_edges, show_arrows, and show_markers keyword arguments.

Hiding a layer often improves the visualization's responsiveness.

note

To hide the map layer, set the tile_layer_opacity component keyword argument to 0.

`show_nodes`

Kind: SylvereyeRoadNetwork component keyword argument
Type: bool
Default: True

Set to False to hide the nodes layer (hides every node). Set to True to show the layer.

caution

Setting this keyword argument to True does not re-reveal nodes that were hidden through the NodeVisibilityMethod.CUSTOM visibility method. The two controls compose: a node is shown only if show_nodes is True and the per-node visible field permits it.

`show_edges`

Kind: SylvereyeRoadNetwork component keyword argument
Type: bool
Default: True

Set to False to hide the edges layer (hides every edge). Set to True to show the layer.

caution

Setting this keyword argument to True does not re-reveal edges that were hidden through the EdgeVisibilityMethod.CUSTOM visibility method.

`show_arrows`

Kind: SylvereyeRoadNetwork component keyword argument
Type: bool
Default: True

Set to False to hide the direction-arrows layer (hides every arrow). Set to True to show the layer.

caution

Setting this keyword argument to True does not re-reveal arrows that belong to edges hidden through the EdgeVisibilityMethod.CUSTOM visibility method.

`show_markers`

Kind: SylvereyeRoadNetwork component keyword argument
Type: bool
Default: True

Set to False to hide the markers layer (hides every marker). Set to True to show the layer.

caution

Setting this keyword argument to True does not re-reveal markers that were hidden through the MarkerVisibilityMethod.CUSTOM visibility method.

Map keyword arguments

The map keyword arguments configure the center, zoom level, and CSS style of the underlying map.

See the Leaflet.js documentation for the format and accepted values of these arguments.

`map_center`

Kind: SylvereyeRoadNetwork component keyword argument
Type: list
Default: [38.64, -90.24] (St. Louis, MO)

Sets or updates the map center, given as a pair of [lat, lon] coordinates.

tip

Always set map_center to a location relevant to your road network. The fallback is St. Louis only because the underlying map needs a starting position before your data loads.

`map_zoom`

Kind: SylvereyeRoadNetwork component keyword argument
Type: int
Default: 3

Sets or updates the map zoom level.

`map_min_zoom`

Kind: SylvereyeRoadNetwork component keyword argument
Type: int
Default: 3

Sets or updates the minimum allowed zoom level.

`map_max_zoom`

Kind: SylvereyeRoadNetwork component keyword argument
Type: int
Default: 20

Sets or updates the maximum allowed zoom level.

`map_style`

Kind: SylvereyeRoadNetwork component keyword argument
Type: dict
Default: {'width': '100%', 'height': '98vh'}

Sets or updates the CSS style applied to the map. The value is a dictionary mapping CSS property names to their values.

note

Use this keyword argument to set the dimensions (width and height) of the Dash Sylvereye visualization.

Example:

{'width': '100%', 'height': '98vh'}

Tile-layer keyword arguments

The tile-layer keyword arguments configure the URL, attribution, subdomains, and opacity of the map's tile layer.

Any tile layer that works with Leaflet.js will work with Dash Sylvereye.

See the Leaflet.js documentation for the format and accepted values of these arguments.

`tile_layer_url`

Kind: SylvereyeRoadNetwork component keyword argument
Type: str
Default: 'https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png'

The tile-layer URL template.

`tile_layer_attribution`

Kind: SylvereyeRoadNetwork component keyword argument
Type: str
Default: '© <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'

The HTML attribution displayed for the tile layer.

`tile_layer_subdomains`

Kind: SylvereyeRoadNetwork component keyword argument
Type: str
Default: "abc"

The subdomains used to load tiles. Each character is interpreted as a single subdomain that may replace the {s} token in tile_layer_url.

caution

A tile-layer URL that contains {s} requires a non-empty tile_layer_subdomains. The OpenStreetMap default URL uses {s} and the default "abc" covers it. If you swap in a tile provider whose URL has no {s}, the value is ignored.

`tile_layer_opacity`

Kind: SylvereyeRoadNetwork component keyword argument
Type: float
Default: 1.0

The tile-layer opacity. Must be a value between 0 and 1.0, inclusive.

tip

Set this keyword argument to 0 to hide the tile layer entirely (useful when you want to render only the road network on a blank background).

Keyword arguments​

Dash keyword arguments​

id​

Data keyword arguments​

nodes_data​

edges_data​

markers_data​

Options keyword arguments​

node_options​

edge_options​

marker_options​

debug_options​

Show/hide keyword arguments​

show_nodes​

show_edges​

show_arrows​

show_markers​

Map keyword arguments​

map_center​

map_zoom​

map_min_zoom​

map_max_zoom​

map_style​

Tile-layer keyword arguments​

tile_layer_url​

tile_layer_attribution​

tile_layer_subdomains​

tile_layer_opacity​

Keyword arguments

Dash keyword arguments

`id`

Data keyword arguments

`nodes_data`

`edges_data`

`markers_data`

Options keyword arguments

`node_options`

`edge_options`

`marker_options`

`debug_options`

Show/hide keyword arguments

`show_nodes`

`show_edges`

`show_arrows`

`show_markers`

Map keyword arguments

`map_center`

`map_zoom`

`map_min_zoom`

`map_max_zoom`

`map_style`

Tile-layer keyword arguments

`tile_layer_url`

`tile_layer_attribution`

`tile_layer_subdomains`

`tile_layer_opacity`