Multiple image request and every taken date by WMTS

Apps / Services
#1

Here is what I am trying to do and hope to know how to do.

Requesting the most recent 7 imageries by WMTS to show on the same web page.
How is “the most recent 7 imageries” possible?

No requesting of the imageries taken in the specific date nor time range.
Just need most recent 7 imageries.

Need to know every taken date of that responded imageries to show on the web page.
How is it possible?

#2

The best option would be to use the Catalogue functionality to get the relevant dates, see this example:

Alternate option is to use WFS set MAXCC=100, TIME parameter to e.g. 3 months (7 images is about 1.5 months, so 3 months should be more than sufficient) and MAXFEATURES=7.

After you have the relevant dates, you simply construct the WMTS requests setting the TIME parameter to the appropriate date, e.g. TIME=2020-11-16/2020-11-16.

#3

@gmilcinski In case of WFS, is it possible to get relevant dates with better output format and automatically put it into WMTS request without user operation? I tried WFS way that you kindly advice me and get JSON file downloaded. If there are some ways that is not needed to open and read the downloaded file to find the relevant dates, that is so helpful.
My web application is very simple.
(1) click satellite view link
(2) show 7 most recent satellite images with 7 taken dates.

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#4

The API, as it is commonly so, returns one output. If you really wanted, you could configure our process API in a way to return a multi-part response, e.g. 7 images packed in the GZIP. But I do not think this would help you much.

For the use-case describe, you will have to implement this part on the web-application level. There is no need for user to do anything as the process can be automatic. It has to be implemented by you though, e.g. in JavaScript:
-you first trigger WFS to get dates
-then construct a web-site with appropriate image SRCs-es.

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#5

Is it possible to filter and display the images we have listed with the CATOLOG API as in sentinel-playground?
To give a concrete example, I am trying to make a web-service where I can display all the images of March for the specified corn field and apply NDVI index.
I can list dates with the catalog api or I can apply indexes like ndvi with the process api, but is it possible to call all images in the date range from the selectbox?

I would be glad if you could help,
Thanks!

#6

Perhaps it would be esiest if you try to use Sentinel Playground directly, it is open source:

The “select box” part has to be implemented by you as it is not part of the Sentinel Hub API (it is implemented in Sentinel Playground though). Once you select the “date”, you can then pass this parameter to the API and visualise NDVI on that specific date.

#7

Thanks for your answer, but I’m trying to apply this process to thousands of agricultural fields. I can list the available dates with distinct(), my question is: how can I display the images in the given date interval separately.

#8

Not sure I understand your question. You cannot have different dates within the same WMTS request. You will have to execute one request for every combination of AOI/date period.