how can i solve this error appears when I try reading position

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Hello:
I am trying to read the position (latitude and longitde) from a data with thingSpeakRead and the next error appears:
Dot indexing is not supported for variables of this type
This is my code from MATLAB Visualizations code:
data = thingSpeakRead(1299642, 'location',true)
lon = data.Longitude;
lat = data.Latitude;
figuregeoplot(lat,lon,'red-*')
geobasemap("topographic")
title("Ground Truth Trajectory")
And this is the output:
data =
[]
Dot indexing is not supported for variables of this type.
Error in Posicion (line 3)lon = data.Longitude;
Someone knows what is happening?
Thank you
  1 Comment
KSSV
KSSV on 5 Apr 2021
Just run this line:
data = thingSpeakRead(1299642, 'location',true)
There is no data, it is empty. As the data is empty you are getting error from the next line data.. Check this line alone why the data is empty.

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Answers (1)

Vinod
Vinod on 5 Apr 2021
Your channel is empty, and you are trying to index into an empty array retrieved from the channel. Try this:
data = thingSpeakRead(1299642, 'location',true)
if ~isempty(data)
lon = data.Longitude;
lat = data.Latitude;
figuregeoplot(lat,lon,'red-*')
geobasemap("topographic")
title("Ground Truth Trajectory")
end

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