I'm trying to turn a PNG that looks like this to a shapefile with polygons that keep the categories marked by the colors on the map.

[![enter image description here][1]][1]

I have several maps to process, so manually tracing the polygons is not a valid option.

I tried to do this with `arcpy.RasterToPolygon`, [from here][2] :

    import arcpy
    from arcpy import env
    env.workspace = "C:/data"
    arcpy.RasterToPolygon_conversion("zone", "c:/output/zones.shp", "NO_SIMPLIFY",
                                      "VALUE")

In this case "zone" is the input PNG, this layer is already georeferenced to its actual location. zones.shp is the filename where I want to store the new features.

I get the following error:

    Runtime error  Traceback (most recent call last):   
    File "<string>", line 5, in <module>   
    File "c:\program files (x86)\arcgis\desktop10.4\arcpy\arcpy\conversion.py", line 337, in RasterToPolygon     
    raise e ExecuteError: ERROR 010151: No features found in c:\gis\output\control_test.shp. 
    Possible empty feature class. Failed to execute (RasterToPolygon).

Is it possible to fix this error or to use another function to get to my goal?

I have the original PNG as an SVG with vector drawn polygons if that helps.


  [1]: https://i.sstatic.net/2baAg.png
  [2]: http://pro.arcgis.com/en/pro-app/tool-reference/conversion/raster-to-polygon.htm