I am a student of economics and I am conducting my master thesis on cultural industries. Trying to understand what is the feeling of the people about different themes, I'am using TwitteR package in R and in particular the function searchtwitter. everything works fine but when I am trying to geocode the tweets(geocode is an argument of the function) the results provided are very few. I have tried with different coordinates and setting also the argument "since" and "until" but significant results are obtained only if I don't set the argument "geocode", "since", "until". Poorly speaking I obtain a relevant number of tweets but I don't know their provenience. Do you know some strategy to deal with this issue? Are there better programs to map feelings posted by people on social network?
There are 3 things that are decreasing your search results count:
The Twitter Search API only gives results about 1 week back.
Only a fraction of tweets are geo-tagged.
Search terms may be too specific.
There isn't too much to do about 1 and 2, but for 3, I can recommend getting familiar with Advanced Search. You can construct a query with the website, then use the same query string in the code. As an example, one of my queries has a query string with 366 characters, mostly OR statements and then a few exclude (-) statements.
If you post some specific examples, maybe the community can help more.