Cannot display the map and mapdata correctly

Dear Sir or Madam,

I am testing to use widget to display map and the plotted values.according to the example. But it always shows the big map (see upper picture) instead of showing the more detailed location map picture (see lower picture). Are the 'location' and 'Location', 'Timestamps' are the build-in variables? I put my fields names 'LatitudeX', 'LongitudeY' as in the setting. Please advise how to do and fix it. Many thanks.

Answer 1

[Christopher Stapels]

Locations are not automatically filled in. If your device writes data to the fields Latitude and Longitude then they will exist

Like this

https://api.thingspeak.com/update.json?api_key=<write_api_key>&field1=123&lat=43.10&long=71.2

Then then you read the channel data and set location =1 (or true), you get the position data in the response.

mydata=thingSpeakRead(876466,'location',1,'outputformat','timetable')

mydata = 1x6 timetable
         Timestamps         CounterValue    SoilMoisture    TemperatureF    Latitude    Longitude    Altitude
    ____________________    ____________    ____________    ____________    ________    _________    ________

    02-Oct-2019 12:46:58         37             767            66.74         42.299      -71.352       NaN   

If you are writing the sensor data to your channel in fields called LattitudeY and LongitudeY you can get the data from those variables for plotting.

mydata=thingSpeakRead(yourChannel,'outputformat','timetable')

(psuedodata)

timeStamps sensordata1 sensordata2 LatitudeX LongitudeY

12:23 1.2 2.3 43.1 77.9

Can you share the link to the example you are refering to?

[Aaron]

Thanks verh much. I cannot use the datatip or plot the coordinate labels (latituude and longitude vlues, timestamp) beside the map data points in the geoscatter map. Please advise how to resolve it. Many thanks.

No functions after adding the code below.

plot (sensorData.Timestamps,sensorData.LatitudX) ylabel('^0F'); hold;

yyaxis right plot(sensorData.Timestamps,sensorData.LongitudY); ylabel('position'); ylim([700 900]); hold off; and

[Walter Roberson]

geoscatter() plots on a GeographicAxes, which does not work with regular plot(). You need to geoplot() instead of regular plot()

However... it makes no sense at all to plot time based data on a geographic axis.

[Aaron]

Thanks. Could you advise how to use geoplot to display the values of latitude and longitude beside each ploted point. Many thanks.

[Christopher Stapels]

I would use text function to get the valeus on it, after you do the geoplot. There is also annotation, but I think that is better for single callouts not general labeling.

[Aaron]

Dear Sir, Thanks very much. I cannot update a text character, say, abc into, say, field4 using https://api.thingspeak.com/update.json?api_key....... Only numeric number can be updated. Why? How can I update a text onto the field?

Aaron

[Vinod]

I just confirmed that you can update the field values with text using this API. For example:

https://api.thingspeak.com/update?api_key=<YOUR_WRITE_API_KEY>&field1=abc

You can confirm the value by reading the value using this API. For example:

https://api.thingspeak.com/channels/<YOUR_CHANNEL_ID>/feeds.json?results=1&api_key=<CHANNEL_READ_API_KEY>

Note that if you insert non-numeric values into the fields, you will need to use MATLAB to generate the output visualization. Built-in field charts only work on numeric values.