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I am trying to use Zonal Statistics to find the most common value of a high-resolution classification within a coarser fishnet grid (10x10 m). The idea is to use this high-res classification as training data for a classification using Sentinel 2 data. Original High-res classificationThe fishnet was made using the Sentinel 2 data as a template and then rasterized. All raster operations (e.g. rasterizing the high-res classification, which was vector data) have used this fishnet raster as a snap raster. However, when I use Zonal Statistics (Statistics Type: Majority) to find this most common value, I get wrong results. For example, a cell which has only a small percentage of 'Brown' (small dump hill) values is assigned as having a majority of 'Brown' cells (see screenshot). Zonal Statistics using Sentinel cell size For this Zonal Statistics operation, I used the Sentinel cell size (10 m). When I use the cell size of the original classification (~2.3 cm), I do get the expected results ('Yellow', which is bare ground) (see screenshot below), but then I get way too many cells, which is a problem for further operations (the screenshot below seems like it has a coarse cell size, but these are actually millions of small (2.3 cm) cells.Zonal Statistics using original cell size

How is it possible that ArcGIS Pro assigns a 'Brown' value to a cell which barely any 'Brown' in it? And why does this not happen in all cells that have small amounts of 'Brown' in them? Should I not use the Sentinel cell size as output cell size for Zonal Statistics?

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  • @Hornbydd Okay, I've done that now. Thanks!
    – stijnionio
    Apr 21 at 15:46
  • What are the actual cell values of a brown and yellow pixels in your high-res data? If yellow is NODATA then that may be the cause. Edit your question to expand on what your data values are. Also the black grid lines (your fishnet) I assume are 10m x10m in size, correct?
    – Hornbydd
    Apr 21 at 16:13
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    @Hornbydd Updated the question to tell what the values reflect. Brown is a small dump hill and yellow is bare ground. Correct, the grid lines are 10 by 10 meters
    – stijnionio
    Apr 21 at 16:16

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