Dear Tawhid Hossain

You can combine your image with a topographic map and you can find out about the water level. This method is common in determining the flood plain area. For topographic map you can also use satellite images and all process can be done easily in ArcGIS.

Good Luck

Pirouz

Dear Tawhid Hossain

You can combine your image with a topographic map and you can find out about the water level. This method is common in determining the flood plain area. For topographic map you can also use satellite images and all process can be done easily in ArcGIS.

Good Luck

Pirouz

If your lake is large enough you can consider using altimetry data from ERS or ICESat.

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There is a nice open-source toolbox for altimetry (BRAT) and a page with excellent explanations but the whole topic is still quite involved and complex:

www.altimetry.info

https://earth.esa.int/web/sentinel/user-guides/software-tools/-/article/brat

Hi Tawhid. As Mr. Behrouz said, you will need topographic data, may be from a paper map or a DEM if it has enough resolution for your study area. The procedure is simple, just find some points in the image that appears to be on a clear shore (beware of trees over the shore) and then you measure the heigh of those points and use the most probable (mean height or more common etc.)

Bear in mind the projection of the data and the horiz/vertical resolution of both the image and the elevation data.

Hope it helps ;)

How much of a change in water level do you anticipate to measure? You can use band C SAR (e.g. Sentinel-1 or RADARSAT-2) for interferrometry of 4-6 cm, but you'll need a reference elevation, possibly from a DEM, which you can download from the ASTER site.

Modified Normalised Difference Water Index will work. MNDWI can be used to classify the water bodies based on these thresholds:

• Class shallow water pixels = -0.614 < MNDWI < -0.834
• Class Dense Water pixels = MNDWI > -0.834
• Class No water pixels = MNDWI < -0.615