Hello
I’m trying to plot information on a map using Dash, but it’s behaving weirdly. When I try to filter the information using a dropdown, it doesn’t filter properly. I try this:
df = unexpected_events[unexpected_events['Participant'] == unexpected_participants]
But the output is an empty data frame, it won’t plot anything on the map, I tried to do an operation with one of the columns, and it gets mad…
Traceback (most recent call last):
File "/path/lib/python3.6/site-packages/flask/app.py", line 1997, in __call__
return self.wsgi_app(environ, start_response)
File "/path/lib/python3.6/site-packages/flask/app.py", line 1985, in wsgi_app
response = self.handle_exception(e)
File "/path/lib/python3.6/site-packages/flask/app.py", line 1540, in handle_exception
reraise(exc_type, exc_value, tb)
File "/path/lib/python3.6/site-packages/flask/_compat.py", line 33, in reraise
raise value
File "/path/lib/python3.6/site-packages/flask/app.py", line 1982, in wsgi_app
response = self.full_dispatch_request()
File "/Users/scrapworksinc/.virtualenvs/sw-ai/lib/python3.6/site-packages/flask/app.py", line 1614, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/path/lib/python3.6/site-packages/flask/app.py", line 1517, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/path/lib/python3.6/site-packages/flask/_compat.py", line 33, in reraise
raise value
File "/path/lib/python3.6/site-packages/flask/app.py", line 1612, in full_dispatch_request
rv = self.dispatch_request()
File "/path/lib/python3.6/site-packages/flask/app.py", line 1598, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/path/lib/python3.6/site-packages/dash_auth/basic_auth.py", line 35, in wrap
response = f(*args, **kwargs)
File "/path/lib/python3.6/site-packages/dash/dash.py", line 556, in dispatch
return self.callback_map[target_id]['callback'](*args)
File "/path/lib/python3.6/site-packages/dash/dash.py", line 513, in add_context
output_value = func(*args, **kwargs)
File "/path/app.py", line 130, in unexpected_map
cmax=max(df['HR']),
ValueError: max() arg is an empty sequence
As a sanity check, I use dash_table_experiments to create a table, and it works, then I tried to print the operation, and it works…
@app.callback(
dash.dependencies.Output('output-a', 'children'),
[dash.dependencies.Input('unexpected_participants', 'value')])
def callback_a(unexpected_participants):
df = unexpected_events[unexpected_events['Participant'] == unexpected_participants]
return 'Your max number is "{}"'.format(max(df['HR']))
The callback for the map is:
@app.callback(
Output('unexpected_map', 'figure'),
[Input('unexpected_participants', 'value')])
def unexpected_map (unexpected_participants):
df = unexpected_events[unexpected_events['Participant'] == unexpected_participants]
data = [dict(
type = 'scattergeo',
locationmode = 'USA-states',
lon = df['Longitude'],
lat = df['Latitude'],
mode = 'markers',
marker = dict(
size = 8,
opacity=0.8,
cmin=0,
color=df['HR'],
# cmax=max(df['HR']),
colorbar=dict(
title='Values'
)
),
name = 'HR')]
layout = dict(
title = 'Something',
showlegend = True,
geo = dict(
scope='usa',
projection=dict( type='albers usa' ),
showland = True,
landcolor = 'rgb(217, 217, 217)',
subunitwidth=1,
countrywidth=1,
subunitcolor="rgb(255, 255, 255)",
countrycolor="rgb(255, 255, 255)"
),
)
fig = dict( data=data, layout=layout )
return {'data': data, 'layout': layout}
Am I missing something?
Thanks!