Change the size of points according to the attribute information

Question

Greetings!
My teacher gave me a task and it sounds like this: there are several points with the attribute "Ф". The point with the smallest value of this attribute takes on the smallest size; with the largest - the largest size. Dot size changes should be displayed on the legend.
I ran into 2 problems while doing this.
1) Standard point size.
I'm using archmap version 10.8. I created a point and gave it a size of 20. After deleting it and returning it back to the archmap project, it takes the default size of 4. Is there any way to fix this?
2) Changing the point size.
I decided to do the task with Python, but I couldn't find a method that changes the point size. The only thing I could find is the Symbol class, which, if I understand correctly, is available only for ArcGIS pro 2.8 and 2.9. Since I could not find a suitable method, I replaced the desired point with a polygon, but this is not correct.

I am attaching 2 screenshots: input data (+ attribute table for one of the points) and the result.

HeatherSmith · Accepted Answer

Hello @Landoexist ,

The dot size is part of the symbology, and symbology is not permanent with the data, it is only applied in the map as a way of displaying the data. So it is expected that the symbology disappears and returns to its default state when you remove the data and re-add it to the map. This will be true in ArcMap, in ArcGIS Pro, with Python, or any other option.

Add your data to a map, symbolize it, and save the map. Find out from your teacher how they want you to submit the assignment. It might be a pdf of a map showing the symbols and the legend. It might be the .aprx map document file zipped up with the data. It won't be just the data itself, because the data alone cannot store the symbology and legend.

You can symbolize your data by size in ArcMap usiong either Graduated symbols or Proportional symbols. Here is an example of using Graduated symbols in a lesson: https://learn.arcgis.com/en/projects/get-started-with-arcmap/#subsection-3

Extra information: You may also be interested in saving a layer file. This file will store the layer properties for a dataset, including its symbology.