});

custom-scripts

A repository of custom scripts that can be used with Sentinel-Hub services.

Vegetation Condition Index

Show script or download it or download V3 for use with Sentinel Hub RESTful API.

Evaluate and visualize

Sentinel Hub RESTful API (click to expand)

Save script_v3.js to your current directory and run the below command. Don't forget to insert your actual access token. ```bash curl -X POST \ https://services.sentinel-hub.com/api/v1/process \ -H 'Authorization: Bearer ' \ -F 'request={ "input": { "bounds": { "properties": { "crs": "http://www.opengis.net/def/crs/EPSG/0/4326" }, "bbox": [14.4,45.95,14.6,46.15] }, "data": [{ "dataFilter": { "maxCloudCoverage": 20, "timeRange": { "from": "2015-01-01T00:00Z", "to": "2019-10-10T00:00Z" } }, "type": "S2L1C" }] }, "output": { "width": 512, "height": 512, "responses": [{ "identifier": "default", "format": { "type": "image/png" } }] } }' \ -F "evalscript=@script_v3.js" --output output.png ``` </p> </details> ## General description of the script The vegetation condition index [1] compares the NDVI at current (observed) time to historical values, i.e. to NDVI at similar dates in previous years: VCI = (NDVI_observed - NDVI_hist_min) / (NDVI_hist_max - NDVI_hist_min) Please note that in case of Sentinel 2, only a few years of history are available. The script takes the newest (latest) available scene as the observed one -- thus, the observed date can be chosen in the Sentinel Hub Playground GUI (or, in case of API request, via the ```dataFilter.timeRange.to``` field). Then, for each previous year the script finds the one closest to the same date, but not more than ```toleranceDays``` from that date. Because of the multi-temporal nature of this index, be sure to use it in the temporal version of Sentinel Hub Playground with "Enable temporal data" checked in the "Effects" tab, or in case of API request, set the ```dataFilter.timeRange.to``` field far enough back to include all available history.

The actual scenes (dates) used can be returned as meta-data (click to see details). Meta-data can be retrieved with an API requests by replacing the ```responses``` part of the request with: ```json "responses": [{ "identifier": "userdata", "format": { "type": "application/json" } }] ``` Example response: ```json { "historical": [ "2018-09-08T00:00:00.000Z", "2016-09-13T00:00:00.000Z", "2015-09-09T00:00:00.000Z" ], "observed": "2019-09-13T00:00:00.000Z" } ```
## Description of representative images Vegetation condition index of Rome. Acquired on 8.10.2017. ![Vegetation condition index of Rome](/custom-scripts/sentinel-2/vegetation_condition_index/fig/fig1.png) ## References [1] https://www.indexdatabase.de/db/i-single.php?id=249