Image manipulation

Home > Faq > Image manipulation

How do I get actual NDVI values?

If you want to get float values out of the service, you will have to use 32-bit float image type (as basic 8 and 16bit tiff files only support integeres).

You can define a Custom script along the following lines:

var ndvi = (B08-B04)/(B08+B04); 
  return [ndvi]; 

You can either save this in Configuration utility or you can pass it as EVALSCRIPT parameter. For the latter the example of the call is:

Are EO products being changed through time or is visualization fixed?

When user selects "EO Product template", she can see the Custom script behind each visualization/processing to make it as transparent as possible on what is happening with the data. We are changing these configurations through time, adding new ones and improving existing ones. For those, who want to ensure that processing of their layers is not changed any more, they can simply edit the original Custom script and gain full control over it.

How can I get original reflectance data from the satellite?

To get original reflectance data from the satellite set the custom script accordingly. REFLECTANCE is a physical format, which requires a 32-bit TIFF float. The values ​​are from 0 to 1. See example below:

 https://services.sentinel-hub.com/ogc/wms/{INSTANCE_ID} ...&LAYERS=B04_REFLECTANCE&FORMAT=image/tiff;depth=32f

Custom script example for B04_REFLECTANCE:

return [B04]

Custom script band input values are already in reflectance (hence the simple script).

Pages

Subscribe to RSS - Image manipulation