Identifying new business opportunities, is it by personal connections and market knowledge or by conducting a thorough market research?

Conducting a thorough market research takes into consideration both the personal connections and the market knowledge, otherwise it will not be "thorough".
The personal connections can be used as sources of information for example, and the market knowledge also besides its role in directing the researcher towards the key points and factors.

I would also recommend a combination of both, and more! Market research will provide very good insights about the industry that you would like to invest in, but studies and statistics are not enough, and what worked for others may not go well with you.
Here comes the role of personal contacts and/or specialized consultants.
Another important factor (in my opinion) is personal field research/visits, go down their and see how similar business are operating, the problems that they are facing and how are they becoming successful! To wrap it up you will need: - Market research: Provide statistics, case studies, data, insights, and other information about the industry.
- Personal Contacts/Consultants: Provide personal experience/advice about the industry in the targeted market.
- Field visits: Provide personal contact with similar businesses to have a real feel of the business when it is live.
With all the above in hand you will versed in with all aspects of the business/industry and will have a clearer view to take your decision.
Best of Luck!

Market research is a very important step for identifying new business opportunities, as, among other things, it helps you understand whether your offering is likely to generate demand.
It gives you a clear sense of how to market, where to market, when to market, who to market.
Market knowledge along with connections will help you lead in the market research.
Through the market research process, you can take data - a variety of related or non-related facts - and create useful information to guide your business decisions.
Market research is not an activity conducted only once; it is an ongoing study.
The information gained through marketing research is information that can guide your most important strategic business decisions.
Some of the benefits of market research are: • It guides your communication with current and potential customers.
• It helps you identify opportunities in the marketplace.
• It minimizes the risk of doing business.
• It uncovers and identifies potential problems.
• It creates benchmarks and helps you track your progress.
• It helps you evaluate your success.
Thus, Market research is very important for identifying business opportunities.

Identifying Market potentials and opportunities depends mainly on identifying and analyzing Market map concerning offer and demand.
Also others elements plays a major role like culture background, economic background, Purchasing power and the type of customers.

on market research to gather all necessary information for the SWOT

Hi there combining both will give you a great advantage , if you have the connections , and you are knowing the market then conducting studies after that will give you an accurate indicator , anyone can conduct researches , having the network is more important.
- based on personal experience

If one has personal connections spread and market knowledge covering the entire territory being targeted then it's an ideal condition to grab new business opportunities.
If not then a market research carried in the territory targeted will come out with many not thought of related questions and solutions for the new business opportunities.
Market research is an expensive affair.
However, most of the global principal companies have the market research data available which can be asked for if at all one plans to represent them in the given territory for new business opportunities.
Such data are quite useful in business planning for diversified new business opportunities.

it depends on the identification of the "Business Opportunity" ...
if it is a project that may generate couple of Millions; connection may push things fast; but if you are talking about a complete new Line of Business targeting a specific market, then a comprehensive market research is a Must

Fairly a combination of both and depends on the stage of the company (its position in life cycle) if it is already existing and trying to identify new business prospects. If it is a new entity altogether.. a proposed entity rather, then a thorough market research is fundamental