I have a raster of tree heights from Lidar and a polygon layer where I have sketched the tree crowns by eye from an orthophoto. See screenshot. I want to get the maximum heights within each tree polygon so used zonal statistics as table, but the table returned a load of nonsense. Pixel inspector on the raster layer shows sensible values (around 9 metres for small trees up to 23 metres for the bigger trees, which correlate well with field estimates) but none of the columns in the stats table (below) make sense i.e. the max value ought to equal the max values found with pixel inspector but they dont and the ranges are really big. Any idea what could be the issue?

Example screenshot

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closed as unclear what you're asking by Andre Silva, PolyGeo Oct 20 '16 at 23:03

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    I think a couple examples of the "sensible" and "nonsense" values would help people answer your question. – Dan C Oct 18 '16 at 13:53
  • It looks like the output values are within range of the "Tree_Height" raster, listed in the table of contents. Can you add a screenshot of the raster statistics? – Ben Gosack Oct 18 '16 at 19:36
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    Zonal statistics tools are for use on 2 rasters. I think you need to 'extract by mask' then run statistics on the resulting raster. OR create a raster from the polygon data and run zonal statistics with that and your tree height raster. – jbalk Oct 19 '16 at 3:37
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    In the table screenshot, are minimum values greater than maximum (e.g 64 > 9.764984 where objectid =1)? Can you explain better what the columns in the attribute table are? What is the raster resolution? How did you parameterize the zonal statistics processing? – Andre Silva Oct 19 '16 at 13:53