Questions tagged [normalized-difference-water-index]

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Calculate water frequency in Google Earth Engine based on time series?

I have the Landsat 8 images cover southern Florida during 2017 (from Jan 1st to Dec 31st), with the cloud, scan edges and other bad observation pixels eliminated. I have also calculated several ...
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1answer
33 views

Google Earth Engine -Iterated image of NDWI

I computed the NDWI of the whole image collection and I expect to output an image that shows water body whenever it has been flooded , even once , throughout the filtered date. Somehow the output ...
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1answer
33 views

Why mNDWI can detect the shallow water area but ignores the deep water area?

I'm using Landsat 8 in Google Earth Engine to detect the water body in Jiangsu and Zhejiang area, China. The formula is: mNDWI = (Green-SWIR)/(Green+SWIR) I applied this formula to GEE code, and it ...
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1answer
33 views

How to compute the conditional function and output binary image in GEE?

I am now using Google Earth Engine to process the Landsat 8 images. Now I have calculated NDVI, EVI, mNDWI and generated some maps. I am now want to generate a function based on those indices values, ...
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0answers
16 views

Performing unsupervised classification using ArcGIS Desktop?

How to distinguish between water bodies and clouds using unsupervised classification in sentinel 2? When i used NDWI and NDSI both are same objects.
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30 views

Clip a Mask (NDSI) from another Mask (NDWI) in GEE

I have created a mask of Normalized difference Snow Index (NDSI) in the late winter using a combination of Landsat 5,7,8 imagery and I would like to only keep a remaining land features by clipping out ...
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1answer
210 views

Treatment of Landsat 7 SLC error in Google Earth Engine?

Google Earth Engine distributes Landsat 7 image composites of indeces such as NDWI and NDVI that, when averaged on a shapefile, give back a coherent value. But how is SLC failure treated by it https:/...
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1answer
413 views

How is Landsat NDWI calculated in Google Earth Engine?

I am using Google Earth Engine to compute NDWI time series, in particular by plotting "Landsat 7 Collection 1 Tier 1 8-Day NDWI Composite" data values The product description says: These Landsat 7 ...
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1answer
685 views

Reclassifying NDWI using Google Earth Engine?

I'm trying to reclassify a NDWI raster into 1 for values >0.4 and 0 for <0.4. I understand that its possible to use .remap in case of discrete values, but not sure how to reclassify NDWI raster ...
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2answers
531 views

NDWI Calculation with Surface Reflectance Products

I have downloaded L8 OLI/TIRS C1 Higher Level Data from USGS Earth Explorer to map Chlorophyll content in lake. The file contains original images and surface reflectance images. When I calculate NDWI ...
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1answer
618 views

Binarization of water body extraction in Google Earth Engine?

I'm a new learner of Google Earth Engine. What I am doing right now is to extract water bodies from Landsat 8 using such water index as NDWI(normalized difference water index) in GEE. Is there any ...
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1answer
287 views

Getting extreme values for NDWI calculation for Landsat 8 Imagery

I am currently in a remote sensing course at my university and am working on a change detection project. I am having some trouble creating an ndwi raster from landsat 8 imagery. I am using arcgis 10.5....
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1answer
616 views

How to remove negative values from RasterLayer in R

I am processing Landsat 8 images to detect water quality parameters in R. I am using NDWI to masking the images. The raster layer I obtained from NDWI has negative values which I wanted to remove. Can ...
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2answers
214 views

Applying Maximum Likelihood Classification to a single band (NDWI)

I have applied ML to a single band file, specifically a NDWI (McFeeters version). Comparing the results of this classification, with ML applied too a normal 5 band RapidEye Scene, the first one gave ...
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1answer
796 views

Masking Water Bodies to build surface temperature raster slice of them in ENVI?

I am looking at a region in the Alaskan tundra, there are plenty of small water bodies in my scene. I need to mask these bodies, so that I can perform a surface temperature/emissivity normalization ...
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1answer
161 views

Water discrimination by Remote sensing

I have NIR, green, red edge, red, IR bands at disposal of a an area with a river, I want to discriminate water surfaces, do you have any good ideas on how to do that ? I did a NDWI which is not very ...
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1answer
1k views

Converting Landsat 8 to TOA for NDWI calculation

I am trying to use Landsat to identify small-scale water bodies in Eastern Africa. I first pansharpened a composite image of bands 2-7 to improve the resolution. Bands 2-4 are now at a resolution of ...
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1answer
3k views

How to Calculate NDWI Value in Arcgis 10.1?

I want to delineate surface water feature of my Landsat raster image and also want to calculate the area of water body. I have learned through internet that NDWI can be used to delineate open water ...