I am trying to figure out how to do gradient shading on some polygon noise contours that I have around an airfield based on their dB range. I understand how to break up features by their unique values into categories and use a gradient color scale, but I am wanting each new layer to "fade" into the previous without any clear distinction in a coninuous pattern. To give you an example, here is the map I am trying to reproduce:

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As you can see, the layers are on a very nice gradient scale. There are only 9 layers that I have, one for 85, 80, 75, etc. I am not sure how to break it up this evenly and continuosly.

Here is what I have been able to do so far below: just used simple green/red gradient, took out the outlines and used transparency.

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1 Answer 1


The vector data is a discrete entity (see the comparison of crisp vs. continuous data) in nature. Therefore, you cannot do what you are after without seeing the polygon boundaries, unless you use continuous data. On solution is using raster data, which can be rendered to obtain the desired effect you mentioned.

If you convert your polygons to polyline first, and then use one of the interpolation methods in Interpolation Toolset, you will have a raster data. Then you can use strechted symbology with the desired color scheme, and pick a continuous data resampling method (bilinear or cubic) from Display tab of the raster layer to get what you want.

  • Thank you for the response, I unfortunately don't have the proper license to use any of the Interpolation tools. Is there another way I can go about doing this? As in, could I use the conversion tools and convert my polylines of the contour lines to raster then use a process to create a stretched symbology with a continuous data resampling method?
    – DEB
    Dec 6, 2016 at 14:27
  • 1
    There are a few options in this and another stack exchange questions. I thought from your snapshots that you have polygons that needs to be converted to the polylines first but if you have polylines already, go directly from there.
    – fatih_dur
    Dec 7, 2016 at 7:04

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