If you search in small regions , google maps will show all the results and the app will scrape all the data that you need.
If you are targeting a large region like a state or country than Its better to do several searches with small regions. For example if you want to get all the restaurants in California state, than the query "Restaurants in CA" will not give you all the restaurants in this state, You should do multiple searches by cities in the CA state like below.
Restaurants in Los Angeles , CA
Restaurants in San Francisco , CA
And some times search by city will also not give you all the results if the city is big, in such cases you should search by the Zip codes, below are a couple of sample search terms.
restaurants in Los Angeles, CA 90001
restaurants in Los Angeles, CA 90002
Doing search by zip codes manually will take time, full version can also take a text file as input and automatically make the searches , the text file should contain all the search terms, one search term per line.