Mapping companionship between weeds

Hi.

I have an example dataset as follows (simplified version of a 50K row DB - locations over 1K, Weed types ~500)

| Location     |   Weed   | Risk |
|      A       |   Type 1  | High |
|      B       |   Type 1  | Low  |
|      A       |   Type 2  | High |
|      B       |   Type 2  | Med  |
|      A       |   Type 3  | High |

Basically I'm trying to show if there is any companionship to two weed types growing together on a map.

Just wondering if anyone had any thoguhts about the best way to address this? The correlation should be based on risk where if one weed type is risk High and another weed type in the same location is High or Medium then it should be mapped.

Cheers,

John.