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NDVI Threshold

Differentiates NDVI values into vegetation classes.


Introduction

For more information, please read the block description.

Block type: PROCESSING

Supported parameters

This block applies thresholding for Normalized Difference Vegetation Index (NDVI) values. This block classifies the NDVI values previously generated with processing blocks such as NDVI. However, other similar NDVI blocks on the marketplace can be used with this block.

  • n_sieve_pixels: Number of the connected pixels (small polygon) that will be replaced in the output with value of their largest neighbor.

  • threshold_values: A list of a dictionary with specific vegetation type and corresponding threshold values.

Vegetation types and threshold values

The default threshold values are shown in the table below. However, you can change the vegetation type and threshold_values according to your needs.

Vegetation TypeThreshold
no_vegetation0.2
sparse_vegetation0.4
moderate_vegetation0.6
dense_vegetation0.9

Example queries

Example of the block using n_sieve_pixels and threshold_values in a complete workflow consisting of the data block Pleiades Reflectance (Download), DIMAP -> GeoTIFF Conversion, and NDVI:

{
     "ndvi:1": {
             "output_original_raster": false
     },
     "up42-ndvithreshold:1": {
             "n_sieve_pixels": 5,
             "threshold_values": [{
                     "no_vegetation": 0.2,
                     "dense_vegetation": 0.9,
                     "sparse_vegetation": 0.4,
                     "moderate_vegetation": 0.6
             }]
     },
     "data-conversion-dimap:1": {
             "ms": true,
             "pan": false,
             "clip_to_aoi": false
     },
     "oneatlas-pleiades-fullscene:1": {
             "time": "2018-01-01T00:00:00+00:00/2020-12-31T23:59:59+00:00",
             "limit": 1,
             "order_ids": null,
             "max_cloud_cover": 100
     }
 }