MATLAB Visualizations in ThingSpeak

Hi,

My question is related to this example - https://www.mathworks.com/help/thingspeak/create-heatmap-overlay-image.html

It used an image stored in the web load it using the following command

picture = imread('https://www.mathworks.com/help/examples/thingspeak/win64/CreateHeatmapOverlayImageTSExample_02.png'); 

What is the most convenient way to host a custom image to use the imread() command. Can anyone explain it with steps.

[Walter Roberson]

Could you explain more about what you mean about "host a custom image" ?

If you mean that you want to be able set up an internet-accessible image that people can access, then that is not a MATLAB question. There are a lot of free web-hosting sites around.

[Nipuna]

I have an image, a map of a farmland. I have set up sensors to collect soil moisture values on this farm. I need to create a soil moisture map combining my IOT soil moisture sensors with the plan/image of the farm. I planned to show this map on a field in a channel of ThingSpeak using MatLab vusualization.

The issue I have is where to save the image that I have.. I tried Google photos, Onedrive but the imread() function can not read the image from them.

Also I uploaded it to MatLab drive and tried with the shared file link, it worked/can access until I keep the image on a preview window in MatLab drive. What is the method of image save/host in internet/cloud if I need to access it whenever I use MatLab visulisation.

[Walter Roberson]

It is possible to imread() a photo from Google Photos. However, the way to get the correct URL is obscure; the test I just did, the secret URL was over 800 characters of pretty random characters like P8PeurrnqmOMvBwVWkia-jeJQL6HPYz8boUvfvQ3GE

Answer 1

[Vinod]

You can upload your files into your MATLAB Drive for sharing. It will require the user to log in to MATLAB Drive to access it. MATLAB can also save files into DropBox and read file out of DropBox programmatically using a dropbox token.

If you are looking for an alternative only for images - one that does not require a login, there are many options out there.

[Nipuna]

Hi Vinod,

Thanks for that image hosting links. Out of the 11 options in that links I was able to sucessfully read image files using the imread() command only from https://publit.io/ image hoster. I found most of other image sharing services sharing links do not support the format the imread() command as mentioned in https://www.mathworks.com/help/matlab/ref/imread.html. I did not tried the DropBox option since I only have to access an image file.

Thanks for the feedback

[Vinod]

I've used Imgur in the past successfully. The key there is to post the image, then right click on the image in the browser and select "copy image url" and use the image url in MATLAB. See:

img = imread('https://i.imgur.com/IEkjCYz.jpg');
imshow(img);