I am struggling with extracting NDVI values for particular shapefiles from an entire raster dataset of NDVI in ArcGIS 10.4.

[NaisargiDave]

I have a geotiff 16 bit multispectral data which converted to NDVI. Now I have about 30 polygons which are basically buffer strips on a stream and I want average, minimum and maximum NDVI value for each polygon. I used extract by mask tool and it works fine if I have a single polygon. It does not have an attribute table but I can still identify these values by changing the symbology to unique values. However, when I use a shapefile that has 30 different polygons, what I get is a data which shows me the mean, median, minimum and maximum of all the unique values of 30 polygons combined. What I want is 30 different numbers. The only way I know as of now is drawing 30 different shapefiles and then extracting each of them separately. Can someone suggest me a good way of doing this? 

[DanPatterson_Retired]

Zonal Statistics or better, zonal statistics as table

http://desktop.arcgis.com/en/arcmap/latest/tools/spatial-analyst-toolbox/zonal-statistics-as-table.h...

[NaisargiDave]

I tried running both, but I end up getting an empty raster as output. I added my shapefile in input feature data and NDVI layer for input value raster. I wonder what is it that I am doing wrong here. 

[DanPatterson_Retired]

Yes, your raster and the polygon file are not in the same coordinate system

[NaisargiDave]

Ok, I think the issue was that I was using a tiff file for raster data, which did not work but the actual NDVI raster layer works. But, even after the successful zonal statistics, I still have only 1 row in the table, instead of 30 rows showing me values of each polygon distinctively. (Also, I noticed when I export NDVI raster to a .tif format using export data, the values of NDVI somehow change, I don't know why)

[ChrisDonohue__GISP]

Not sure if this is the  best approach, but it sounds like one way to do this would be to use Modelbuilder or Python to Iterate through the polygons and therefore run the analysis on each one individually.

Examples of using iterators in ModelBuilder—Tools | ArcGIS Desktop 

Chris Donohue, GISP

[NaisargiDave]

Thanks Chris, that was helpful. I am not familiar with Python but I tried Modelbuilder and got an execution error. I am sure it's a problem with my data format or something else. I tried exporting my shapefiles to a feature class. I checked all the coordinate systems. I will keep trying. On the side note, still continuing with 30 different polygons. But I would still like to learn.