Firefly Cartography

16 thoughts on “Firefly Cartography”

  1. Hi John,
    This is a great article and I’m trying it out. I’m stuck on ‘Glows are a radial gradient’. I can create a similar glow around points using layered symbology similar to the polygon glow, but is there a way to apply a radial gradient to a point layer? (in ArcGIS Pro or ArcMap 10).


      1. That makes sense. I’ve never made custom markers, but I’m going to try it out.

        I found that point gradient in pro, but you’re right. You can set one end to No Color, but it shows up as grey. I’d guess Photoshop would do a better job rendering than Arc anyway.



  2. Hey John,
    I really love your work. It inspired me to do a firefly map as well. I really like your glowing dots and I’m wondering if you have a qualitative version as well as the quantitative ones you linked above?
    I am going to try to make my own but my photoshop skills are pretty weak.

    Thanks for sharing your amazing cartography with us!


  3. Really appreciate all these resources John. I’ve reviewed everything Firefly in Living Atlas. I’ve imported the .Png points into my ArcMap style file, and they work! I see the tutorial for light saberin’ in ArcPro. Is it possible to create glow lines for hydrographic polygon/polyline features in Desktop and/or AGOL WebMaps? If the answer is obvious, feel free to volley back a RTFM.


  4. Do you do anything to make them cluster together? I’m trying out the technique, and I’m not sure I’m getting the same clustering effect that you have.


    1. Hmmm, not sure what you mean about clustering. Some of these examples show points that are positioned near each other. But the Firefly point style is just a glowing dot, per feature. No clustering algorithm. Just a visual effect of the glowing dots aggregating in visual intensity because they are nearby eachother. No actual computational clustering.


  5. John, how did you “desaturate” the imagery. Did you use some of the Conversion raster functions in ArcGIS Pro, custom image stretch, or some other method? Any advice would be much appreciated.


    1. There are a few different ways you can do this. The easiest way is just to use the Firefly basemap, which is grayscale when zoomed out and more and more saturated when zoomed in.
      Alternatively, I would recommend using a blend mode. If you add this “global background” layer over the imagery basemap and give it a “color” blend mode, it will make the imagery appear grayscale. If you reduce the transparency of the global background layer then the underlying imagery will look more saturated. You can adjust to your preference.


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