Proportional symbols combined with different colors for outline

Question

Hi everyone, I have a question about a specific use of proportional symbology with point shapefile. I have data representing trees with attributes of crown radius (in meters) and vitality (values 1-5) and I need to display the trees as circles with the crown radius so that the outline color changes with the vitality attribute (see image).

If I use a proportional symbology for the crowns, the only way I can get it to look like I need is to copy the layer five times and use Definition Query to symbolise each value with different outline color. Vary symbology by attribute doesn't work as it changes only the color of the filling. And if I use Unique values symbology, the size of circles is changeable, but can only be used if I want to display the data in one scale of map and calculate the proper size.

Is there any easier way to combine these symbology properties (as I know it is possible in qgis), or do I have to continue with using Definition Query?

ZuzanaFialova · Answer

Hi,

thanks for the reply. At first glance this looks like it could be a good workaround and I might try it, but I'm not entirely sure it's usable for me.

I would prefer, if I didn't need to create several layers, since sometimes I need to create several maps using different attributes with several values (e.g. vitality, age, taxon,...) and it could easily become a hundred new layers. Also I might have the need to edit some values and that would mean to run this every time I do so.

So it would seem that for now one layer displayed several times using definition query is better for me. As it displays any changes immediately.

JonathanDandois · Answer

So through some trial and error, some ChatGPT, and a trip deep into the CIM docs and JSON (Python CIM Access) i was able to get  a Python notebook going to do something like this.

In my use case, I had measures of square footage per building within different categories of usage type (classroom, office, etc). My customer wants proportional symbols to show the true scale of "40,000 SF of classroom in this building vs 2,000 SF of classroom in that building". Each of the different usage types gets a different color.

The arcpy script runs in a notebook:

* It uses a single template layer in the map that is already configured with Proportional Symbol, Area US Feet , for my use case. 
* It loops over each of the unique usage types, makes a new layer based on the template and assigns it a new name based on the usage type value.
* Then goes deep into the CIM (this took some trial and error) and updates the color property of the symbols for that layer based on a lookup table defined in the script to get the correct color. 
* By default, the MakeFeatureLayer adds the new layer to the map.

Note that if a different symbol is used, the CIM dot notation around lines 46,47 needs to be modified for the CIM JSON structure for that symbol.

YMMV.

arcpy_CIM_color_Layers_share.py

JonathanDandois · Answer

Hello, just commenting that I have the same challenge, but the only work-around is to create separate layers for each attribute-driven category and assign a unique color to that layer.

With Proportional Symbols selected, checking "Allow symbol property connections" does not appear to allow color to be changed based on a attribute value.