robin1
February 2, 2023, 9:17am
1
The following five lines draws a chart using plotly:
import plotly.graph_objects as go
x_time=["09:31:00", "09:32:00", "09:33:00", "09:34:00", "09:35:00", "09:36:00", "09:37:00", "09:38:00", "09:39:00", "09:40:00"]
y1=[6.37,6.42,6.39,6.50,6.42,6.48,6.43,6.54,6.46,6.56]
fig = go.Figure(go.Scatter(x=x_time, y=y1, mode='lines', name='y1', line=dict(color="#ff0000")))
fig.show()
When looking at the chart in a web browser I would like to draw a straigth line using the mouse to see how well I can connect the lows in that uptrend to form a trendline. How can I do that? If using a tool that automatically tries to find the best trendline for me I might want to manually adjust it afterwards if I know some data points have less value. Thanks a lot for any suggestions!
AIMPED
February 2, 2023, 9:21am
2
HI @robin1 welcome to the forums!
You can use a builtin function for that:
serch on this page for Drawing shapes with a Mouse on Cartesian plots
1 Like
robin1
February 2, 2023, 12:18pm
3
Thank you very much, fantastic, seems to work!
AIMPED
February 2, 2023, 2:35pm
4
Hi @robin1 , that’s unfortunately not possible. If you are open to use Dash, it’s perfectly achievable.
robin1
February 2, 2023, 4:46pm
5
Absolutely, I am also using Dash when plotting data realtime! Can you please give me a hint how to do this in Dash?
AIMPED
February 2, 2023, 7:10pm
6
Hi @robin1 ,
The shapes (in your case the line) are stored in a list of the figure.layout.
Fisrt thing to do, would be extractiong the shape information.
Second step would be creating the new shape based on your needs and add this new shape to the list.
third step would be updating the figure
I have some apps in my github dealing with shapes, this one for example:
from dash import Dash, dcc, html, Input, Output, State
import dash_bootstrap_components as dbc
from dash.exceptions import PreventUpdate
import plotly.graph_objects as go
import numpy as np
# prepare trace data
data = go.Scatter(
x=[1, 10],
y=[1, 10],
mode='markers',
marker={
'size': 8,
'symbol': 'circle-open',
},
)
# create figure
fig = go.Figure(data=data)
show original
It’s a bit different than what you want to do, but the basic principle is the same.
In this example I create annotations on mouse click:
from dash import Dash, dcc, html, Input, Output, State
import dash_bootstrap_components as dbc
from dash.exceptions import PreventUpdate
import plotly.express as px
import numpy as np
# create image and plotly express object
img = np.random.randint(0, 255, (90, 160))
fig = px.imshow(img, color_continuous_scale='Blugrn')
# update layout
fig.update_layout(
template='plotly_dark',
plot_bgcolor='rgba(0, 0, 0, 0)',
paper_bgcolor='rgba(0, 0, 0, 0)',
width=700,
height=500,
margin={
'l': 0,
'r': 0,
show original