API

Keyword arguments

The SylvereyeRoadNetwork Dash component is the core component of the Dash Sylvereye library.

The SylvereyeRoadNetwork component can be imported from the dash_sylvereye module as follows:

from dash_sylvereye import SylvereyeRoadNetwork

The SylvereyeRoadNetwork component supports 21 keyword arguments classified as follows:

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

The following is a depiction of all SylvereyeRoadNetwork keyword arguments, including their default values:

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)

Any of the keyword arguments is mandatory.

Thanks to Dash's architecture, any of the SylvereyeRoadNetwork keyword arguments (excepting id) can be updated at runtime to update the visualization, usually as a reaction to the user's interaction with other Dash components.

Dash keyword arguments

These are keyword arguments mandated by Dash. For now the only Dash keyword argument is id:

id

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

The identifier of the Dash component.

Data keyword arguments

SylvereyeRoadNetwork needs to pieces of data to know the road network topology: nodes and edges. Nodes and edges are supplied separately through the nodes_data and edges_data keyword arguments, respectively.

You usally populate nodes_data and edges_data from OSMnx-generated data by using load_from_osmnx_graph and load_from_osmnx_graphml functions. You can populate nodes_data and edges_data manually, as well.

In addition, SylvereyeRoadNetwork supports the visualization of markers. Markers data are supplied through the markers_data keyword argument.

You usually populate markers_data from a list of coordinates pairs by using the generate_markers_from_coords function. You can populate markers_data manually, as well.

nodes_data

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

The list of the road network's nodes. Each item of the list must be a node. Please refer to this page to see the format 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 of the list must be and edge. Please refer to this page to see the format 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 of the list must be a marker. Please refer to this page to see the format each marker item must follow.

Options keyword arguments

The visualization options for nodes, edges, and markers are provided as dictionaries, separately.

The node_options keyword argument allows the programmer to set up different color, size, and transparency methods for nodes.

You usually first get a pre-filled default node_options dictionary by using the get_default_node_options function, then modify it according to your needs, and finally pass it to SylvereyeRoadNetwork through the node_options keyword argument.

The edge_options keyword argument allows the programmer to set up different color, width, and transparency methods for edges.

You usually first get a pre-filled default edge_options dictionary by using the get_default_edge_options function, then modify it according to your needs, and finally pass it to SylvereyeRoadNetwork through the edge_options keyword argument.

The marker_options keyword argument allows the programmer to set up different color, size, transparency, and icon methods for markers.

You usually first get a pre-filled default marker_options dictionary by using the get_default_marker_options function, then modify it according to your needs, and finally pass it to SylvereyeRoadNetwork through the marker_options keyword argument.

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. Please refer to this page to see how to set up the supported marker visual options.

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. Please refer to this page to see how to set up the supported edge visual options.

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. Please refer to this page to see how to set up the supported marker visual options.

debug_options

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

The debug options. #TODO

Show/hide keyword arguments

You can hide the different layers of a Dash Sylvereye visualization, namely the nodes, edges, direction arrows, and markers layers, through the show_nodes, show_edges, show_arrows, and show_markers component keyword arguments, respectively.

Note that by hidding any combination of the layers mentioned above you may speed up the visualization response.

Note

To hide the map layer, you can 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, i.e. to hide all nodes. Set to True to show the nodes layer.

Note

Setting this keyword argument to True won't show any node hidden through the NodeVisibilityMethod.CUSTOM visibility method.

show_edges

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

Set to False to hide the edges layer, i.e. to hide all edges. Set to True to show the edges layer.

Note

Setting this keyword argument to True won't show any edge 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, i.e. to hide all direction arrows. Set to True to show the direction arrows layer.

Note

Setting this keyword argument to True won't show any direction arrow 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, i.e. to hide all markers. Set to True to show the markers layer.

Note

Setting this keyword argument to True won't show any marker hidden through the MarkerVisibilityMethod.CUSTOM visibility method.

Map keyword arguments

Map keyword arguments allow you to setup the center, zoom, and CSS style of the map.

Please refer to the docs in the Leaflet.js website for more information about the format/values of these keyword arguments.

map_center

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

Use this keyword argument to initialize/update the map center. The center is a pair of [lat, lon] coordinates.

map_zoom

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

Use this keyword argument to initialize/update the map zoom level.

map_min_zoom

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

Use this keyword argument to initialize/update the minimum allowed map level.

map_max_zoom

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

Use this keyword argument to initialize/update the maximum allowed map level.

map_style

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

Use this keyword argument to initialize/update the map CSS style. It is a dictionary where keys are style names and values are style values.

Note

You can use this keyword argument to set the dimensions (width, height) of the Dash Sylvereye visualization.

Example:

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

Tile layer keyword arguments

Map keyword arguments allow you to setup the following properties of the tile map layer: URL, attribution, subdomains, and opacity.

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

Please refer to the docs in the Leaflet.js website for more information about the format/values of these keyword 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: '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'

The tile layer attribution HTML text.

tile_layer_subdomains

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

The tile layer subdomains.

tile_layer_opacity

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

The tile layer opacity. It must be a value between 0 and 1.0 (inclusive).

Note

Set this keyword argument to 0 to hide the tile map layer.

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