What factors make Google show local listings on organic results?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

• 
  NeotericUK LTD .: On what factors Google show local listings on organic results ? i have tried for" London hotels" it shows but not for "London design agencies" ?? Why ??
  
  +Jim Munro ;
• 
  Kalpesh Bharankar: +Jim Munro it is just a Google Algo. and we do not have control over it. I have also observed for some of the keywords where google was showing the local listings, now the listings are removed and result of 10 website taken place instead, what we see usually.
• 
  Rob Wagner: So you have tried for "London hotels" and you are showing. However, it does not show for ;"London design agencies". I think +Tim Capper ;could answer this better than me but maybe do the same thing for ;"London design agencies" as you did for ;"London hotels". I think we are going to need more information. Is it the same site or different site. ;
• 
  Tim Capper: This is a tough one because only Google knows what triggers a local listing merge.
  
  mapmaker shows around 400 companies that appear for london design agencies.
  
  My personal theory is that - local search results are not triggered for search terms that do not appear for categories that are not provided by google places.
  
  Example, a category that is available is : design consultant which if you search london design consultant you get a local listing trigger.
  
  However.... web designer is a category and london web designer does not trigger.
  
  So, the moral of the story is only Google knows
• 
  Jim Munro: Maybe Google is like a pitboss. If there are too many players, maybe they just say "Bust everybody". :)
• 
  NeotericUK LTD .: +Rob Wagner We are just observing it on random basis .. not for particular site... and +Tim Capper what you have discussed can be possible but we have to do lot more research on it. if you get to know something else on it then please share thanks for your time and response.
• 
  Sunny K. Ujjawal: Google Maps search results are based primarily on relevance, distance, and prominence. These factors are combined to help us find the best match for your search.
  https://support.google.com/places/answer/7091?hl=en
  
  Also, ;Reviews carry a lot of weight, both with search engines and would be customers. You must get serious about this aspect of local search.
• 
  NeotericUK LTD .: +Tim Capper you are right as per our research again on it and we have tried lots of Google places categories and also their synonyms with the name of location and it works it shows only to categories which are defined in Google places
   ;here is a list of categories http://blumenthals.com/google-lbc-categories/search.php?q=&val=hl-gl%3Den-US%26ottype%3D1
• 
  Edwin Jonk: From the expert panel in this weeks SEO Questions hangout on air on 02:13:52 into the YouTube video: https://dumbseoquestions.com/q/what_factors_make_google_show_local_listings_on_organic_results +NeotericUK LTD
  
  The cuetimes listed on this page are functional while the live broadcast continues and also once Youtube has finished processing the public broadcast. Processing time varies between 6-24 hours. During this period the clip is viewable in full but the cuetimes cannot be relied on.