Reference
Utility functions
Dash Sylvereye ships a handful of utility functions for common tasks such as building marker lists and fetching default option dictionaries.
generate_markers_from_coords
generate_markers_from_coords builds a Dash Sylvereye marker list from a list of [lat, lon] coordinates.
It can be imported from the dash_sylvereye.utils module.
The following example places a marker on top of each node in the road network:
from dash_html_components import Div
from dash_sylvereye import SylvereyeRoadNetwork
from dash_sylvereye.utils import generate_markers_from_coords
# fill a list with the coordinates of every node
# 'nodes_data' is a preloaded Dash Sylvereye nodes list
markers_coords = [[node["lat"], node["lon"]] for node in nodes_data]
# make markers out of the list of node coordinates
markers_data = generate_markers_from_coords(markers_coords)
# dashboard setup
# 'app' is the app Dash object
app.layout = Div([
SylvereyeRoadNetwork(
...
nodes_data=nodes_data,
markers_data=markers_data
...
)
])
The following example places a custom marker on top of each node, with a tooltip that displays the marker's coordinates on hover:
from dash_html_components import Div
from dash_sylvereye import SylvereyeRoadNetwork
from dash_sylvereye.utils import generate_markers_from_coords
CUSTOM_ICON_ID = "my_custom_marker"
CUSTOM_ICON_FILEN = "custom_marker.svg"
# fill a list with the coordinates of every node
# 'nodes_data' is a preloaded Dash Sylvereye nodes list
markers_coords = [[node["lat"], node["lon"]] for node in nodes_data]
# make tooltips out of the coordinates of every marker
markers_tooltips = [f'My coords are: {coords}' for coords in markers_coords]
# make markers out of the list of node coordinates
markers_data = generate_markers_from_coords(markers_coords, CUSTOM_ICON_ID, CUSTOM_ICON_FILEN, markers_tooltips)
# dashboard setup
# 'app' is the app Dash object
app.layout = Div([
SylvereyeRoadNetwork(
...
nodes_data=nodes_data,
markers_data=markers_data
...
)
])
Parameters
Name: coords
Type: list of list
List of coordinate pairs, one [lat, lon] pair per marker.
Name: icon_id
Type: str
Default: 'custom_marker'
Optional custom ID for the custom icon.
Name: icon_filen
Type: str
Default: Empty string
Optional file name of a custom SVG icon to assign to every marker.
Name: tooltips
Type: list of str
Default: Empty list
Optional list of tooltip strings, one tooltip string per marker.
Returns
Type: list of dict
Dash Sylvereye markers list.
get_edge_middle_coords
get_edge_middle_coords returns the [lat, lon] coordinates at the midpoint of the given edge.
This is useful when you want to draw markers directly on top of edges.
It can be imported from the dash_sylvereye.utils module.
The following example places a marker at the midpoint of each edge in the road network:
from dash_html_components import Div
from dash_sylvereye import SylvereyeRoadNetwork
from dash_sylvereye.utils import generate_markers_from_coords, get_edge_middle_coords
# fill a list with the coordinates at the middle of each edge
# 'edges_data' is a preloaded Dash Sylvereye edges list
marker_coords = [get_edge_middle_coords(edge['coords']) for edge in edges_data]
# make markers out of the list of edge coordinates
markers_data = generate_markers_from_coords(marker_coords)
# dashboard setup
# 'app' is the app Dash object
app.layout = Div([
SylvereyeRoadNetwork(
...
edges_data=edges_data,
markers_data=markers_data
...
)
])
Parameters
Name: edge
Type: list of list
The list of coordinate pairs that make up the edge.
Returns
Type: list of float
The pair of coordinates at the midpoint of the edge.
get_default_node_options
get_default_node_options returns a fresh copy of the default node_options dictionary.
The usual flow: call this function to obtain the pre-filled defaults, override the keys you want to change, and pass the result to SylvereyeRoadNetwork through the node_options parameter.
The returned dictionary looks like this:
{
"color_method": NodeColorMethod.DEFAULT,
"color_default": 0xa10000,
"size_method": NodeSizeMethod.DEFAULT,
"size_default": 0.005,
"alpha_method": NodeAlphaMethod.DEFAULT,
"alpha_default": 1.0,
"visibility_method": NodeVisibilityMethod.ALWAYS
}
This function can be imported from the dash_sylvereye.defaults module.
The returned dictionary is a fresh copy.
Mutating it does not affect future calls to get_default_node_options, nor the defaults used internally by the Dash Sylvereye component.
The following example uses get_default_node_options to set the alpha of every node to 0.5:
from dash_html_components import Div
from dash_sylvereye import SylvereyeRoadNetwork
from dash_sylvereye.defaults import get_default_node_options
# nodes options setup
node_options = get_default_node_options()
node_options['alpha_default'] = 0.5
# set the 'node_options' parameter of the SylvereyeRoadNetwork component
# 'app' is the Dash app object.
app.layout = Div([
SylvereyeRoadNetwork(
...
node_options=node_options,
...
)
])
Parameters
This function has no parameters.
Returns
Type: dict
A fresh copy of the default node_options dictionary.
get_default_edge_options
get_default_edge_options returns a fresh copy of the default edge_options dictionary.
The usual flow: call this function to obtain the pre-filled defaults, override the keys you want to change, and pass the result to SylvereyeRoadNetwork through the edge_options parameter.
The returned dictionary looks like this:
{
"color_method": EdgeColorMethod.DEFAULT,
"color_default": 0x06696,
"width_method": EdgeWidthMethod.DEFAULT,
"width_default": 0.25,
"alpha_method": EdgeAlphaMethod.DEFAULT,
"alpha_default": 1.0,
"alpha_min": 0.0,
"visibility_method": EdgeVisibilityMethod.ALWAYS,
"show_edge_hit_polygons": False
}
This function can be imported from the dash_sylvereye.defaults module.
The returned dictionary is a fresh copy.
Mutating it does not affect future calls to get_default_edge_options, nor the defaults used internally by the Dash Sylvereye component.
The following example uses get_default_edge_options to set the alpha of every edge to 0.5:
from dash_html_components import Div
from dash_sylvereye import SylvereyeRoadNetwork
from dash_sylvereye.defaults import get_default_edge_options
# edges options setup
edge_options = get_default_edge_options()
edge_options['alpha_default'] = 0.5
# set the 'edge_options' parameter of the SylvereyeRoadNetwork component
# 'app' is the Dash app object.
app.layout = Div([
SylvereyeRoadNetwork(
...
edge_options=edge_options,
...
)
])
Parameters
This function has no parameters.
Returns
Type: dict
A fresh copy of the default edge_options dictionary.
get_default_marker_options
get_default_marker_options returns a fresh copy of the default marker_options dictionary.
The usual flow: call this function to obtain the pre-filled defaults, override the keys you want to change, and pass the result to SylvereyeRoadNetwork through the marker_options parameter.
The returned dictionary looks like this:
{
"color_method": MarkerColorMethod.DEFAULT,
"color_default": 0x066cc,
"icon_method": MarkerIconMethod.DEFAULT,
"size_method": MarkerSizeMethod.DEFAULT,
"size_default": 0.25,
"size_default_scale_min": 0.25,
"size_default_scale_max": 0.5,
"alpha_method": MarkerAlphaMethod.DEFAULT,
"alpha_default": 1.0,
"visibility_method": MarkerVisibilityMethod.ALWAYS,
"enable_zoom_scaling": False,
"enable_tooltips": False
}
This function can be imported from the dash_sylvereye.defaults module.
The returned dictionary is a fresh copy.
Mutating it does not affect future calls to get_default_marker_options, nor the defaults used internally by the Dash Sylvereye component.
The following example uses get_default_marker_options to set the alpha of every marker to 0.5:
from dash_html_components import Div
from dash_sylvereye import SylvereyeRoadNetwork
from dash_sylvereye.defaults import get_default_marker_options
# markers options setup
marker_options = get_default_marker_options()
marker_options['alpha_default'] = 0.5
# set the 'marker_options' parameter of the SylvereyeRoadNetwork component
# 'app' is the Dash app object.
app.layout = Div([
SylvereyeRoadNetwork(
...
marker_options=marker_options,
...
)
])
Parameters
This function has no parameters.
Returns
Type: dict
A fresh copy of the default marker_options dictionary.
TODO: debug_options