## IMAGINE Discussions

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New Contributor
Posts: 2
Registered: ‎12-06-2019

# calculating Water indices

Hello Everybody,

we know that we can extract water body content Using NDWI index from Erdas Imagine

But what if we need more details, more indices such as water salinity ( as we can meausre soil salinity )

or water tempreture ( Landsat thermal band doesn't help if we are dealing with small lakes or rivers )

etc..

So How we can calculate or just get close to it

waiting your reply and we can discuss together the best senario or solution

Thanks & Regards

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Technical Evangelist
Posts: 640
Registered: ‎02-02-2016

## Re: calculating Water indices

Hi Moustafa,

If you are aware of water salinity and temperature indices that has been designed for particular sensors please share the formulas so that we can help you create a spatial model to implement them.

Kind regards,

Stephen Bent

Hexagon Geospatial Support

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New Contributor
Posts: 2
Registered: ‎12-06-2019

## Re: calculating Water indices

Hi Stephen,

unfortunately I still don't have any formulas,

Actually I have an area of study "industrial lakes"
and I can get Water parameters through sensors in the lakes

the questions that i'm facing now :

1- how can I get an exact formula from in situ sensor measurments?
2- how many times shoud i depend on these measurments ?
3- how can i use satellite images to predict via DN values after that?

Thanks & Regards

Highlighted
Contributor
Posts: 24
Registered: ‎06-12-2016

## Re: calculating Water indices

Hello, hope this helps !

Normalized Difference Salinity Index (NDSI) = [1600:1700]−[2145:2185] / [1600:1700]+[2145:2185]

Wavelenghts: 1600:1700,2145:2185 ( ASTER: B4-B5/B4+B5 )

Best regards,

Marian