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I'm new to ArcMap 10.2 and trying to get NDVI data of city centers.

So my problem is, after I'm calculating the NDVI and getting the result raster, I would like to get a mean (average) value of specifically and only the area I select (which is the city center on a 1:50000 scale).

Things I tried and didn't make me happy;

1) Identify tool. It constantly gives me the information about only ONE pixel even if I draw an area on raster image with shift + click. 2) Clipping raster from View > Data Frame Properties > Data Frame > Clipping tool. Even after I crop the satellite image to 1:50000 area I'm interested in, I can still get information from blank places OUTSIDE of my area, and it also affects the mean value of AOI NDVI.

So basically, I want to get an accurate mean NDVI value ONLY including the pixels of the selected area of interest.

I'm using LANDSAT 7 and 8 satellite images which are way larger than my AOI.

Sorry for bad English.

1 Answer 1

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I am assuming you have a shapefile defining 'area of interest (city center). If yes,then you can use zonal statistics tool (require spatial analyst extension) where

in_zone_data = shapefile of city center

in_value_raster = raster image

Edit: If you don't have spatial analyst, why not clip the aoi using data management -> raster toolset -> raster processing -> clip and then get mean from attribute table? I think given your aoi is 1, this would be even simpler then above method.

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  • 1) I don't have a shapefile. But I have spatial analyst tool. 2) Clipping from raster processing didn't work for me, I zoomed until 1:50000 scale and wrote X, Y values of bottom left as minimum, and top right as maximum. It just created the same original files without clipping them. Again, I'm only using two Landsat Satellite Image bands to calculate NDVI.
    – ErenKvnc
    Jan 6, 2019 at 17:29

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